Release 0.4.1

Cursor movement during port drag-and-drop on the graph is now being tracked
and a link is drawn from the dragged port to the cursor.

If the cursor is hovering a port the source port can link to,
the second end of the link instead attaches to the ports link anchor
so that the link "snaps" to the linkable port.

.gitignore

@@ -1,2 +1,3 @@
+/.flatpak-builder
 /.vscode
 /target

.gitlab-ci.yml

@@ -1,6 +1,6 @@
 include:
   - project: 'freedesktop/ci-templates'             # the project to include from
-    ref: '98f557799157ebb0395cf11d40f01f61fbbace20' # git ref of that project
+    ref: '34f4ade99434043f88e164933f570301fd18b125' # git ref of that project
     file: '/templates/fedora.yml'                   # the actual file to include
 
 stages:
@@ -10,14 +10,14 @@ stages:
   - extras
 
 variables:
-  FDO_UPSTREAM_REPO: 'ryuukyu/helvum'
+  FDO_UPSTREAM_REPO: 'pipewire/helvum'
 
 # Version and tag for our current container
 .fedora:
   variables:
-    FDO_DISTRIBUTION_VERSION: '34'
+    FDO_DISTRIBUTION_VERSION: '38'
     # Update this to trigger a container rebuild
-    FDO_DISTRIBUTION_TAG: '2021-05-06.0'
+    FDO_DISTRIBUTION_TAG: '2023-08-17.0'
 
 build-fedora-container:
   extends:

Cargo.toml

@@ -1,11 +1,12 @@
 [package]
 name = "helvum"
-version = "0.2.1"
+version = "0.4.1"
 authors = ["Tom A. Wagner <tom.a.wagner@protonmail.com>"]
-edition = "2018"
+edition = "2021"
+rust-version = "1.70"
 license = "GPL-3.0-only"
 description = "A GTK patchbay for pipewire"
-repository = "https://gitlab.freedesktop.org/ryuukyu/helvum"
+repository = "https://gitlab.freedesktop.org/pipewire/helvum"
 readme = "README.md"
 keywords = ["pipewire", "gtk", "patchbay", "gui", "utility"]
 categories = ["gui", "multimedia"]
@@ -13,10 +14,10 @@ categories = ["gui", "multimedia"]
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-gtk = { git = "https://github.com/gtk-rs/gtk4-rs/", package = "gtk4" }
+pipewire = "0.7"
-pipewire = { git = "https://gitlab.freedesktop.org/pipewire/pipewire-rs", branch = "main" }
+gtk = { version = "0.7", package = "gtk4" }
+glib = { version = "0.18", features = ["log"] }
 
 log = "0.4.11"
-env_logger = "0.8.2"
 
 once_cell = "1.7.2"

LICENSE

@@ -1,7 +1,7 @@
                     GNU GENERAL PUBLIC LICENSE
                        Version 3, 29 June 2007
 
- Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
  Everyone is permitted to copy and distribute verbatim copies
  of this license document, but changing it is not allowed.
 
@@ -631,8 +631,8 @@ to attach them to the start of each source file to most effectively
 state the exclusion of warranty; and each file should have at least
 the "copyright" line and a pointer to where the full notice is found.
 
-    Helvum
+    <one line to give the program's name and a brief idea of what it does.>
-    Copyright (C) 2020  Ryuukyu
+    Copyright (C) <year>  <name of author>
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -645,14 +645,14 @@ the "copyright" line and a pointer to where the full notice is found.
     GNU General Public License for more details.
 
     You should have received a copy of the GNU General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 Also add information on how to contact you by electronic and paper mail.
 
   If the program does terminal interaction, make it output a short
 notice like this when it starts in an interactive mode:
 
-    Helvum  Copyright (C) 2020  Ryuukyu
+    <program>  Copyright (C) <year>  <name of author>
     This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
     This is free software, and you are welcome to redistribute it
     under certain conditions; type `show c' for details.
@@ -664,11 +664,11 @@ might be different; for a GUI interface, you would use an "about box".
   You should also get your employer (if you work as a programmer) or school,
 if any, to sign a "copyright disclaimer" for the program, if necessary.
 For more information on this, and how to apply and follow the GNU GPL, see
-<http://www.gnu.org/licenses/>.
+<https://www.gnu.org/licenses/>.
 
   The GNU General Public License does not permit incorporating your program
 into proprietary programs.  If your program is a subroutine library, you
 may consider it more useful to permit linking proprietary applications with
 the library.  If this is what you want to do, use the GNU Lesser General
 Public License instead of this License.  But first, please read
-<http://www.gnu.org/philosophy/why-not-lgpl.html>.
+<https://www.gnu.org/licenses/why-not-lgpl.html>.

README.md

@@ -1,6 +1,10 @@
 Helvum is a GTK-based patchbay for pipewire, inspired by the JACK tool [catia](https://kx.studio/Applications:Catia).
 
-![Screenshot](screenshot.png)
+![Screenshot](docs/screenshot.png)
+
+<a href="https://flathub.org/apps/details/org.pipewire.Helvum"><img src="https://flathub.org/assets/badges/flathub-badge-en.png" width="300"/></a>
+
+<a href="https://repology.org/project/helvum/versions"><img src="https://repology.org/badge/vertical-allrepos/helvum.svg" width="300"/></a>
 
 # Features planned
 
@@ -9,22 +13,51 @@ Helvum is a GTK-based patchbay for pipewire, inspired by the JACK tool [catia](h
 
 More suggestions are welcome!
 
-# Distribution packages
-
-- ArchLinux:
-  - [aur/helvum](https://aur.archlinux.org/packages/helvum)
-  - [aur/helvum-git](https://aur.archlinux.org/packages/helvum-git)
-
 # Building
+
+## Via flatpak
+If you don't have the flathub repo in your remote-list for flatpak you will need to add that first:
+```shell
+$ flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
+```
+
+Then install the required flatpak platform and SDK, if you dont have them already:
+```shell
+$ flatpak install org.gnome.{Platform,Sdk}//43 org.freedesktop.Sdk.Extension.rust-stable//22.08 org.freedesktop.Sdk.Extension.llvm14//22.08
+```
+
+To compile and install as a flatpak, clone the project, change to the project directory, and run:
+```shell
+$ flatpak-builder --install flatpak-build/ build-aux/org.pipewire.Helvum.json
+```
+
+You can then run the app via
+```shell
+$ flatpak run org.pipewire.Helvum
+```
+
+## Manually
 For compilation, you will need:
 
+- Meson
 - An up-to-date rust toolchain
 - `libclang-3.7` or higher
 - `gtk-4.0` and `pipewire-0.3` development headers
 
-To compile, run
+To compile and install, run
 
-    $ cargo build --release
+```shell
+$ meson setup build && cd build
+$ meson compile
+$ meson install
+```
 
 in the repository root.
-The resulting binary will be at `target/release/helvum`.
+This will install the compiled project files into `/usr/local`.
+
+# License and Credits
+Helvum is distributed under the terms of the GPL3 license.
+See LICENSE for more information.
+
+Parts of the build system were taken from the [gtk-rust-template](https://gitlab.gnome.org/World/Rust/gtk-rust-template) project,
+which is provided under the terms of the [MIT license](https://gitlab.gnome.org/World/Rust/gtk-rust-template/-/blob/master/LICENSE.md).

build-aux/dist-vendor.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+export DIST="$1"
+export SOURCE_ROOT="$2"
+
+cd "$SOURCE_ROOT"
+mkdir "$DIST"/.cargo
+cargo vendor > $DIST/.cargo/config
+# Move vendor into dist tarball directory
+mv vendor "$DIST"

build-aux/org.pipewire.Helvum.json

@@ -0,0 +1,40 @@
+{
+    "app-id": "org.pipewire.Helvum",
+    "runtime": "org.gnome.Platform",
+    "runtime-version": "43",
+    "sdk": "org.gnome.Sdk",
+    "sdk-extensions": [
+        "org.freedesktop.Sdk.Extension.rust-stable",
+        "org.freedesktop.Sdk.Extension.llvm14"
+    ],
+    "command": "helvum",
+    "finish-args": [
+        "--socket=fallback-x11",
+        "--socket=wayland",
+        "--device=dri",
+        "--share=ipc",
+        "--filesystem=xdg-run/pipewire-0"
+    ],
+    "build-options": {
+        "append-path": "/usr/lib/sdk/rust-stable/bin:/usr/lib/sdk/llvm14/bin",
+        "prepend-ld-library-path": "/usr/lib/sdk/llvm14/lib",
+        "build-args": [
+            "--share=network"
+        ]
+    },
+    "modules": [
+        {
+            "name": "Helvum",
+            "buildsystem": "meson",
+            "sources": [
+                {
+                    "type": "dir",
+                    "path": "../"
+                }
+            ],
+            "config-opts": [
+                "-Dprofile=development"
+            ]
+        }
+    ]
+}

data/icons/meson.build

@@ -0,0 +1,9 @@
+install_data(
+  '@0@.svg'.format(base_id),
+  install_dir: iconsdir / 'hicolor' / 'scalable' / 'apps'
+)
+
+install_data(
+  '@0@-symbolic.svg'.format(base_id),
+  install_dir: iconsdir / 'hicolor' / 'symbolic' / 'apps',
+)

data/icons/org.pipewire.Helvum-symbolic.svg

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg height="16px" viewBox="0 0 16 16" width="16px" xmlns="http://www.w3.org/2000/svg">
+    <path d="m 3.5 2.5 h 9 c 1.378906 0 2.5 1.121094 2.5 2.5 v 5 c 0 1.378906 -1.121094 2.5 -2.5 2.5 h -9 c -1.378906 0 -2.5 -1.121094 -2.5 -2.5 v -5 c 0 -1.378906 1.121094 -2.5 2.5 -2.5 z m 0 0" fill="#241f31" fill-rule="evenodd"/>
+    <g fill="none" stroke="#8a8891">
+        <path d="m 11 7.5 h -6"/>
+        <path d="m 5 7.5 c 0 -4.15625 -1.382812 -10.855469 -3.90625 -13.25" stroke-linecap="round" stroke-linejoin="bevel" stroke-width="4"/>
+    </g>
+</svg>

data/icons/org.pipewire.Helvum.svg

@@ -0,0 +1,56 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg height="128px" viewBox="0 0 128 128" width="128px" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+    <linearGradient id="a" gradientUnits="userSpaceOnUse">
+        <stop offset="0" stop-color="#9a9996"/>
+        <stop offset="0.5" stop-color="#c0bfbc"/>
+        <stop offset="1" stop-color="#deddda"/>
+    </linearGradient>
+    <linearGradient id="b" x1="26.263471" x2="26.263586" xlink:href="#a" y1="24.848538" y2="37.1125"/>
+    <linearGradient id="c" gradientUnits="userSpaceOnUse" x1="7.39555839647" x2="120.60350567947" y1="82.86737386462" y2="82.86737386462">
+        <stop offset="0" stop-color="#5e5c64"/>
+        <stop offset="0.0384615" stop-color="#77767b"/>
+        <stop offset="0.0768555" stop-color="#5e5c64"/>
+        <stop offset="0.923077" stop-color="#5e5c64"/>
+        <stop offset="0.961538" stop-color="#77767b"/>
+        <stop offset="1" stop-color="#5e5c64"/>
+    </linearGradient>
+    <linearGradient id="d" gradientTransform="matrix(2.571428 0 0 2.454545 22.856596 -228.048061)" x1="16" x2="16" xlink:href="#a" y1="121.582512" y2="127.082512"/>
+    <linearGradient id="e" gradientTransform="matrix(2.571428 0 0 2.454545 22.856596 -253.563246)" x1="16" x2="16" xlink:href="#a" y1="121.582512" y2="127.082512"/>
+    <linearGradient id="f" gradientTransform="matrix(2.571428 0 0 2.454545 60.592569 -253.563246)" x1="16" x2="16" xlink:href="#a" y1="121.582512" y2="127.082512"/>
+    <linearGradient id="g" gradientTransform="matrix(2.571428 0 0 2.454545 60.592569 -228.048061)" x1="16" x2="16" xlink:href="#a" y1="121.582512" y2="127.082512"/>
+    <linearGradient id="h" gradientTransform="matrix(2.358499 0 0 2.251294 -11.472502 -204.652927)" gradientUnits="userSpaceOnUse" x1="12.5" x2="19.5" y1="113.832512" y2="113.832512">
+        <stop offset="0" stop-color="#c0bfbc"/>
+        <stop offset="0.5" stop-color="#9a9996"/>
+        <stop offset="1" stop-color="#c0bfbc"/>
+    </linearGradient>
+    <linearGradient id="i" gradientTransform="matrix(2.571428 0 0 2.454545 -14.879853 -228.048061)" x1="16" x2="16" xlink:href="#a" y1="121.582512" y2="127.082512"/>
+    <path d="m 34.519531 30.980469 c 0 3.386719 -3.695312 6.132812 -8.257812 6.132812 c -4.558594 0 -8.253907 -2.746093 -8.253907 -6.132812 s 3.695313 -6.132813 8.253907 -6.132813 c 4.5625 0 8.257812 2.746094 8.257812 6.132813 z m 0 0" fill="url(#b)" fill-rule="evenodd"/>
+    <path d="m 120.601562 82.867188 v 18.867187 c 0 5.226563 -4.207031 9.433594 -9.433593 9.433594 h -94.339844 c -5.226563 0 -9.433594 -4.207031 -9.433594 -9.433594 v -18.867187 z m 0 0" fill="url(#c)" fill-rule="evenodd"/>
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+    <path d="m 93.480469 76.378906 l -30.660157 -24.761718" fill="none" stroke="#77767b" stroke-linecap="square" stroke-width="3.74412"/>
+    <path d="m 64 58.691406 v 10.613282" fill="none" stroke="#999999" stroke-width="1.5"/>
+    <g fill-rule="evenodd">
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+        <path d="m 110.734375 51.617188 c 0 3.726562 -4.027344 6.75 -9 6.75 c -4.96875 0 -9 -3.023438 -9 -6.75 c 0 -3.730469 4.03125 -6.75 9 -6.75 c 4.972656 0 9 3.019531 9 6.75 z m 0 0" fill="url(#f)"/>
+        <path d="m 108.734375 51.617188 c 0 2.898437 -3.132813 5.25 -7 5.25 c -3.863281 0 -7 -2.351563 -7 -5.25 c 0 -2.898438 3.136719 -5.25 7 -5.25 c 3.867187 0 7 2.351562 7 5.25 z m 0 0" fill="#3d3846"/>
+    </g>
+    <path d="m 101.734375 58.691406 v 10.613282" fill="none" stroke="#999999" stroke-width="1.5"/>
+    <path d="m 112.734375 77.132812 c 0 4.554688 -4.921875 8.25 -11 8.25 c -6.074219 0 -11 -3.695312 -11 -8.25 c 0 -4.558593 4.925781 -8.25 11 -8.25 c 6.078125 0 11 3.691407 11 8.25 z m 0 0" fill="#e01b24" fill-rule="evenodd"/>
+    <path d="m 110.734375 77.132812 c 0 3.726563 -4.027344 6.75 -9 6.75 c -4.96875 0 -9 -3.023437 -9 -6.75 c 0 -3.730468 4.03125 -6.75 9 -6.75 c 4.972656 0 9 3.019532 9 6.75 z m 0 0" fill="url(#g)" fill-rule="evenodd"/>
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+    <path d="m 33.261719 77.132812 c 0 2.898438 -3.132813 5.25 -7 5.25 c -3.863281 0 -7 -2.351562 -7 -5.25 c 0 -2.902343 3.136719 -5.25 7 -5.25 c 3.867187 0 7 2.347657 7 5.25 z m 0 0" fill="#3d3846" fill-rule="evenodd"/>
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+    <path d="m 30.980469 30.980469 c 0 1.953125 -2.113281 3.539062 -4.71875 3.539062 c -2.601563 0 -4.714844 -1.585937 -4.714844 -3.539062 s 2.113281 -3.539063 4.714844 -3.539063 c 2.605469 0 4.71875 1.585938 4.71875 3.539063 z m 0 0" fill="#1a5fb4" fill-rule="evenodd"/>
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+</svg>

data/meson.build

@@ -0,0 +1,49 @@
+subdir('icons')
+
+desktop_conf = configuration_data()
+desktop_conf.set('icon', base_id)
+desktop_file = configure_file(
+  input: '@0@.desktop.in'.format(base_id),
+  output: '@BASENAME@',
+  configuration: desktop_conf
+)
+
+if desktop_file_validate.found()
+  test(
+    'validate-desktop',
+    desktop_file_validate,
+    args: [
+      desktop_file
+    ],
+  )
+endif
+
+install_data(
+  desktop_file,
+  install_dir: datadir / 'applications'
+)
+
+
+appdata_conf = configuration_data()
+appdata_conf.set('app-id', base_id)
+appdata_file = configure_file(
+  input: '@0@.metainfo.xml.in'.format(base_id),
+  output: '@BASENAME@',
+  configuration: appdata_conf
+)
+
+# Validate Appdata
+if appstream_util.found()
+  test(
+    'validate-appdata',
+    appstream_util,
+    args: [
+      'validate', '--nonet', appdata_file
+    ],
+  )
+endif
+
+install_data(
+  appdata_file,
+  install_dir: datadir / 'metainfo'
+)

data/org.pipewire.Helvum.desktop.in

@@ -0,0 +1,9 @@
+[Desktop Entry]
+Name=Helvum
+GenericName=Patchbay
+Comment=A patchbay for pipewire
+Type=Application
+Exec=helvum
+Terminal=false
+Categories=AudioVideo;Audio;Video;Midi;Settings;GNOME;GTK;
+Icon=@icon@

data/org.pipewire.Helvum.metainfo.xml.in

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- Copyright 2021 Tom A. Wagner <tom.a.wagner@protonmail.com> -->
+<component type="desktop-application">
+    <id>@app-id@</id>
+    <metadata_license>CC-BY-SA-4.0</metadata_license>
+    <project_license>GPL-3.0-only</project_license>
+    <name>Helvum</name>
+    <summary>Patchbay for PipeWire</summary>
+    <description>
+        <p>
+            Helvum is a graphical patchbay for PipeWire.
+            It allows creating and removing connections between applications and/or devices to reroute
+            flow of audio, video and MIDI data to where it is needed.
+        </p>
+    </description>
+    <screenshots>
+        <screenshot type="default">
+            <image>https://gitlab.freedesktop.org/pipewire/helvum/-/raw/main/docs/screenshot.png</image>
+        </screenshot>
+    </screenshots>
+    <launchable type="desktop-id">@app-id@.desktop</launchable>
+    <url type="homepage">https://gitlab.freedesktop.org/pipewire/helvum</url>
+    <url type="bugtracker">https://gitlab.freedesktop.org/pipewire/helvum/-/issues</url>
+    <content_rating type="oars-1.0" />
+    <releases>
+        <release version="0.4.1" date="2023-08-18" />
+        <release version="0.4.0" date="2023-02-12" />
+        <release version="0.3.4" date="2022-02-02" />
+        <release version="0.3.3" date="2022-01-28" />
+        <release version="0.3.2" date="2021-11-30" />
+        <release version="0.3.1" date="2021-09-30" />
+        <release version="0.3.0" date="2021-08-08" />
+        <release version="0.2.1" date="2021-06-06" />
+        <release version="0.2.0" date="2021-05-21" />
+        <release version="0.1.0" date="2021-01-12" />
+    </releases>
+    <kudos>
+        <kodu>HiDpiIcon</kodu>
+        <kudo>ModernToolkit</kudo>
+    </kudos>
+    <developer_name>Tom A. Wagner</developer_name>
+    <update_contact>tom.a.wagner@protonmail.com</update_contact>
+</component>

docs/making_a_release.md

@@ -0,0 +1,22 @@
+# Making a release
+
+The following describes the process of making a new release:
+
+1. In `data/org.pipewire.Helvum.metainfo.xml.in`,
+   add a new `<release>` tag to the releases section with the appropriate version and date.
+
+2. In `meson.build` and `Cargo.toml`, bumb the projects version to the new version.
+
+3. Ensure cargo dependencies are up-to-date by running `cargo outdated` (may require running `cargo install cargo-outdated`) and updating outdated dependencies (including the versions specified in `Cargo.lock`).
+
+4. Commit the changes with the a message of the format "Release x.y.z"
+
+5. Add a tag to the release with the new version and a description from describing the changes as a message (run `git tag -a x.y.z`, then write the message)
+
+6. Make a **new** meson build directory and run `meson dist`.
+   Two files should be created in a `meson-dist` subdirectory:
+
+   `helvum-x.y.z.tar.xz` and 
+   `helvum-x.y.z.tar.xz.sha256sum`
+
+7. Push the new commit and tag to upstream, then create a new release on gitlab from the new tag, the description from the tags message formatted as markdown, and also add the two files from step 6 to the description.

meson.build

@@ -0,0 +1,38 @@
+project(
+  'helvum',
+  'rust',
+  version: '0.4.1',
+  license: 'GPL-3.0',
+  meson_version: '>=0.59.0'
+)
+
+gnome = import('gnome')
+
+base_id = 'org.pipewire.Helvum'
+
+dependency('glib-2.0', version: '>= 2.66')
+dependency('gtk4',     version: '>= 4.4.0')
+dependency('libpipewire-0.3')
+
+desktop_file_validate = find_program('desktop-file-validate', required: false)
+appstream_util = find_program('appstream-util', required: false)
+cargo = find_program('cargo', required: true)
+
+prefix = get_option('prefix')
+bindir = prefix / get_option('bindir')
+datadir = prefix / get_option('datadir')
+iconsdir = datadir / 'icons'
+
+meson.add_dist_script(
+  'build-aux/dist-vendor.sh',
+  meson.project_build_root() / 'meson-dist' / meson.project_name() + '-' + meson.project_version(),
+  meson.project_source_root()
+)
+
+subdir('src')
+subdir('data')
+
+gnome.post_install(
+  gtk_update_icon_cache: true,
+  update_desktop_database: true,
+)

meson_options.txt

@@ -0,0 +1,11 @@
+option(
+  'profile',
+  type: 'combo',
+  choices: [
+    'default',
+    'development'
+  ],
+  value: 'default',
+  description: 'The build profile for Helvum. One of "default" or "development".'
+)
+

src/application.rs

@@ -1,18 +1,28 @@
-use std::cell::RefCell;
+// Copyright 2021 Tom A. Wagner <tom.a.wagner@protonmail.com>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 3 as published by
+// the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// SPDX-License-Identifier: GPL-3.0-only
 
 use gtk::{
     gio,
-    glib::{self, clone, Continue, Receiver},
+    glib::{self, clone, Receiver},
     prelude::*,
     subclass::prelude::*,
 };
-use log::{info, warn};
+use pipewire::channel::Sender;
-use pipewire::{channel::Sender, spa::Direction};
 
-use crate::{
+use crate::{graph_manager::GraphManager, ui, GtkMessage, PipewireMessage};
-    view::{self},
-    GtkMessage, MediaType, PipewireLink, PipewireMessage,
-};
 
 static STYLE: &str = include_str!("style.css");
 
@@ -23,8 +33,8 @@ mod imp {
 
     #[derive(Default)]
     pub struct Application {
-        pub(super) graphview: view::GraphView,
+        pub(super) graphview: ui::graph::GraphView,
-        pub(super) pw_sender: OnceCell<RefCell<Sender<GtkMessage>>>,
+        pub(super) graph_manager: OnceCell<GraphManager>,
     }
 
     #[glib::object_subclass]
@@ -36,11 +46,17 @@ mod imp {
 
     impl ObjectImpl for Application {}
     impl ApplicationImpl for Application {
-        fn activate(&self, app: &Self::Type) {
+        fn activate(&self) {
-            let scrollwindow = gtk::ScrolledWindowBuilder::new()
+            let app = &*self.obj();
+
+            let scrollwindow = gtk::ScrolledWindow::builder()
                 .child(&self.graphview)
                 .build();
-            let window = gtk::ApplicationWindowBuilder::new()
+            let headerbar = gtk::HeaderBar::new();
+            let zoomentry = ui::graph::ZoomEntry::new(&self.graphview);
+            headerbar.pack_end(&zoomentry);
+
+            let window = gtk::ApplicationWindow::builder()
                 .application(app)
                 .default_width(1280)
                 .default_height(720)
@@ -50,16 +66,28 @@ mod imp {
             window
                 .settings()
                 .set_gtk_application_prefer_dark_theme(true);
+            window.set_titlebar(Some(&headerbar));
+
+            let zoom_set_action =
+                gio::SimpleAction::new("set-zoom", Some(&f64::static_variant_type()));
+            zoom_set_action.connect_activate(
+                clone!(@weak self.graphview as graphview => move|_, param| {
+                    let zoom_factor = param.unwrap().get::<f64>().unwrap();
+                    graphview.set_zoom_factor(zoom_factor, None)
+                }),
+            );
+            window.add_action(&zoom_set_action);
+
             window.show();
         }
 
-        fn startup(&self, app: &Self::Type) {
+        fn startup(&self) {
-            self.parent_startup(app);
+            self.parent_startup();
 
             // Load CSS from the STYLE variable.
             let provider = gtk::CssProvider::new();
-            provider.load_from_data(STYLE.as_bytes());
+            provider.load_from_data(STYLE);
-            gtk::StyleContext::add_provider_for_display(
+            gtk::style_context_add_provider_for_display(
                 &gtk::gdk::Display::default().expect("Error initializing gtk css provider."),
                 &provider,
                 gtk::STYLE_PROVIDER_PRIORITY_APPLICATION,
@@ -82,16 +110,15 @@ impl Application {
         gtk_receiver: Receiver<PipewireMessage>,
         pw_sender: Sender<GtkMessage>,
     ) -> Self {
-        let app: Application =
+        let app: Application = glib::Object::builder()
-            glib::Object::new(&[("application-id", &"org.freedesktop.ryuukyu.helvum")])
+            .property("application-id", "org.pipewire.Helvum")
-                .expect("Failed to create new Application");
+            .build();
 
-        let imp = imp::Application::from_instance(&app);
+        let imp = app.imp();
-        imp.pw_sender
+
-            .set(RefCell::new(pw_sender))
+        imp.graph_manager
-            // Discard the returned sender, as it does not implement `Debug`.
+            .set(GraphManager::new(&imp.graphview, pw_sender, gtk_receiver))
-            .map_err(|_| ())
+            .expect("Should be able to set graph manager");
-            .expect("pw_sender field was already set");
 
         // Add <Control-Q> shortcut for quitting the application.
         let quit = gtk::gio::SimpleAction::new("quit", None);
@@ -101,121 +128,6 @@ impl Application {
         app.set_accels_for_action("app.quit", &["<Control>Q"]);
         app.add_action(&quit);
 
-        // React to messages received from the pipewire thread.
-        gtk_receiver.attach(
-            None,
-            clone!(
-                @weak app => @default-return Continue(true),
-                move |msg| {
-                    match msg {
-                        PipewireMessage::NodeAdded{ id, name } => app.add_node(id,name),
-                        PipewireMessage::PortAdded{ id, node_id, name, direction, media_type} => app.add_port(id,name,node_id,direction,media_type),
-                        PipewireMessage::LinkAdded{ id, node_from, port_from, node_to, port_to} => app.add_link(id,node_from,port_from,node_to,port_to),
-                        PipewireMessage::NodeRemoved { id } => app.remove_node(id),
-                        PipewireMessage::PortRemoved { id, node_id } => app.remove_port(id, node_id),
-                        PipewireMessage::LinkRemoved { id } => app.remove_link(id)
-                    };
-                    Continue(true)
-                }
-            ),
-        );
-
         app
     }
-
-    /// Add a new node to the view.
-    pub fn add_node(&self, id: u32, name: String) {
-        info!("Adding node to graph: id {}", id);
-
-        imp::Application::from_instance(self)
-            .graphview
-            .add_node(id, view::Node::new(name.as_str()));
-    }
-
-    /// Add a new port to the view.
-    pub fn add_port(
-        &self,
-        id: u32,
-        name: String,
-        node_id: u32,
-        direction: Direction,
-        media_type: Option<MediaType>,
-    ) {
-        info!("Adding port to graph: id {}", id);
-
-        let imp = imp::Application::from_instance(self);
-
-        let port = view::Port::new(id, name.as_str(), direction, media_type);
-
-        // Create or delete a link if the widget emits the "port-toggled" signal.
-        if let Err(e) = port.connect_local(
-            "port_toggled",
-            false,
-            clone!(@weak self as app => @default-return None, move |args| {
-                // Args always look like this: &[widget, id_port_from, id_port_to]
-                let port_from = args[1].get::<u32>().unwrap();
-                let port_to = args[2].get::<u32>().unwrap();
-
-                app.toggle_link(port_from, port_to);
-
-                None
-            }),
-        ) {
-            warn!("Failed to connect to \"port-toggled\" signal: {}", e);
-        }
-
-        imp.graphview.add_port(node_id, id, port);
-    }
-
-    /// Add a new link to the view.
-    pub fn add_link(&self, id: u32, node_from: u32, port_from: u32, node_to: u32, port_to: u32) {
-        info!("Adding link to graph: id {}", id);
-
-        // FIXME: Links should be colored depending on the data they carry (video, audio, midi) like ports are.
-
-        // Update graph to contain the new link.
-        imp::Application::from_instance(self).graphview.add_link(
-            id,
-            PipewireLink {
-                node_from,
-                port_from,
-                node_to,
-                port_to,
-            },
-        );
-    }
-
-    // Toggle a link between the two specified ports on the remote pipewire server.
-    fn toggle_link(&self, port_from: u32, port_to: u32) {
-        let imp = imp::Application::from_instance(self);
-        let sender = imp.pw_sender.get().expect("pw_sender not set").borrow_mut();
-        sender
-            .send(GtkMessage::ToggleLink { port_from, port_to })
-            .expect("Failed to send message");
-    }
-
-    /// Remove the node with the specified id from the view.
-    fn remove_node(&self, id: u32) {
-        info!("Removing node from graph: id {}", id);
-
-        let imp = imp::Application::from_instance(self);
-        imp.graphview.remove_node(id);
-    }
-
-    /// Remove the port with the id `id` from the node with the id `node_id`
-    /// from the view.
-    fn remove_port(&self, id: u32, node_id: u32) {
-        info!("Removing port from graph: id {}, node_id: {}", id, node_id);
-
-        let imp = imp::Application::from_instance(self);
-        imp.graphview.remove_port(id, node_id);
-    }
-
-    /// Remove the link with the specified id from the view.
-    fn remove_link(&self, id: u32) {
-        info!("Removing link from graph: id {}", id);
-
-        let imp = imp::Application::from_instance(self);
-        imp.graphview.remove_link(id);
-    }
 }

src/graph_manager.rs

@@ -0,0 +1,272 @@
+// Copyright 2021 Tom A. Wagner <tom.a.wagner@protonmail.com>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 3 as published by
+// the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// SPDX-License-Identifier: GPL-3.0-only
+
+use gtk::{glib, prelude::*, subclass::prelude::*};
+
+use pipewire::channel::Sender as PwSender;
+
+use crate::{ui::graph::GraphView, GtkMessage, PipewireMessage};
+
+mod imp {
+    use super::*;
+
+    use std::{cell::RefCell, collections::HashMap};
+
+    use once_cell::unsync::OnceCell;
+
+    use crate::{ui::graph, MediaType, NodeType};
+
+    #[derive(Default, glib::Properties)]
+    #[properties(wrapper_type = super::GraphManager)]
+    pub struct GraphManager {
+        #[property(get, set, construct_only)]
+        pub graph: OnceCell<crate::ui::graph::GraphView>,
+
+        pub pw_sender: OnceCell<PwSender<crate::GtkMessage>>,
+        pub items: RefCell<HashMap<u32, glib::Object>>,
+    }
+
+    #[glib::object_subclass]
+    impl ObjectSubclass for GraphManager {
+        const NAME: &'static str = "HelvumGraphManager";
+        type Type = super::GraphManager;
+        type ParentType = glib::Object;
+    }
+
+    #[glib::derived_properties]
+    impl ObjectImpl for GraphManager {}
+
+    impl GraphManager {
+        pub fn attach_receiver(&self, receiver: glib::Receiver<crate::PipewireMessage>) {
+            receiver.attach(None, glib::clone!(
+                @weak self as imp => @default-return glib::ControlFlow::Continue,
+                move |msg| {
+                    match msg {
+                        PipewireMessage::NodeAdded{ id, name, node_type } => imp.add_node(id, name.as_str(), node_type),
+                        PipewireMessage::PortAdded{ id, node_id, name, direction, media_type } => imp.add_port(id, name.as_str(), node_id, direction, media_type),
+                        PipewireMessage::LinkAdded{ id, port_from, port_to, active} => imp.add_link(id, port_from, port_to, active),
+                        PipewireMessage::LinkStateChanged { id, active } => imp.link_state_changed(id, active),
+                        PipewireMessage::NodeRemoved { id } => imp.remove_node(id),
+                        PipewireMessage::PortRemoved { id, node_id } => imp.remove_port(id, node_id),
+                        PipewireMessage::LinkRemoved { id } => imp.remove_link(id)
+                    };
+                    glib::ControlFlow::Continue
+                }
+            ));
+        }
+
+        /// Add a new node to the view.
+        fn add_node(&self, id: u32, name: &str, node_type: Option<NodeType>) {
+            log::info!("Adding node to graph: id {}", id);
+
+            let node = graph::Node::new(name, id);
+
+            self.items.borrow_mut().insert(id, node.clone().upcast());
+
+            self.obj().graph().add_node(node, node_type);
+        }
+
+        /// Remove the node with the specified id from the view.
+        fn remove_node(&self, id: u32) {
+            log::info!("Removing node from graph: id {}", id);
+
+            let Some(node) = self.items.borrow_mut().remove(&id) else {
+                log::warn!("Unknown node (id={id}) removed from graph");
+                return;
+            };
+            let Ok(node) = node.dynamic_cast::<graph::Node>() else {
+                log::warn!("Graph Manager item under node id {id} is not a node");
+                return;
+            };
+
+            self.obj().graph().remove_node(&node);
+        }
+
+        /// Add a new port to the view.
+        fn add_port(
+            &self,
+            id: u32,
+            name: &str,
+            node_id: u32,
+            direction: pipewire::spa::Direction,
+            media_type: Option<MediaType>,
+        ) {
+            log::info!("Adding port to graph: id {}", id);
+
+            let mut items = self.items.borrow_mut();
+
+            let Some(node) = items.get(&node_id) else {
+                log::warn!("Node (id: {node_id}) for port (id: {id}) not found in graph manager");
+                return;
+            };
+            let Ok(node) = node.clone().dynamic_cast::<graph::Node>() else {
+                log::warn!("Graph Manager item under node id {node_id} is not a node");
+                return;
+            };
+
+            let port = graph::Port::new(id, name, direction, media_type);
+
+            // Create or delete a link if the widget emits the "port-toggled" signal.
+            port.connect_local(
+                "port_toggled",
+                false,
+                glib::clone!(@weak self as app => @default-return None, move |args| {
+                    // Args always look like this: &[widget, id_port_from, id_port_to]
+                    let port_from = args[1].get::<u32>().unwrap();
+                    let port_to = args[2].get::<u32>().unwrap();
+
+                    app.toggle_link(port_from, port_to);
+
+                    None
+                }),
+            );
+
+            items.insert(id, port.clone().upcast());
+
+            node.add_port(port);
+        }
+
+        /// Remove the port with the id `id` from the node with the id `node_id`
+        /// from the view.
+        fn remove_port(&self, id: u32, node_id: u32) {
+            log::info!("Removing port from graph: id {}, node_id: {}", id, node_id);
+
+            let mut items = self.items.borrow_mut();
+
+            let Some(node) = items.get(&node_id) else {
+                log::warn!("Node (id: {node_id}) for port (id: {id}) not found in graph manager");
+                return;
+            };
+            let Ok(node) = node.clone().dynamic_cast::<graph::Node>() else {
+                log::warn!("Graph Manager item under node id {node_id} is not a node");
+                return;
+            };
+            let Some(port) = items.remove(&id) else {
+                log::warn!("Unknown Port (id: {id}) removed from graph");
+                return;
+            };
+            let Ok(port) = port.dynamic_cast::<graph::Port>() else {
+                log::warn!("Graph Manager item under port id {id} is not a port");
+                return;
+            };
+
+            node.remove_port(&port);
+        }
+
+        /// Add a new link to the view.
+        fn add_link(&self, id: u32, output_port_id: u32, input_port_id: u32, active: bool) {
+            log::info!("Adding link to graph: id {}", id);
+
+            let mut items = self.items.borrow_mut();
+
+            let Some(output_port) = items.get(&output_port_id) else {
+                log::warn!("Output port (id: {output_port_id}) for link (id: {id}) not found in graph manager");
+                return;
+            };
+            let Ok(output_port) = output_port.clone().dynamic_cast::<graph::Port>() else {
+                log::warn!("Graph Manager item under port id {output_port_id} is not a port");
+                return;
+            };
+            let Some(input_port) = items.get(&input_port_id) else {
+                log::warn!("Output port (id: {input_port_id}) for link (id: {id}) not found in graph manager");
+                return;
+            };
+            let Ok(input_port) = input_port.clone().dynamic_cast::<graph::Port>() else {
+                log::warn!("Graph Manager item under port id {input_port_id} is not a port");
+                return;
+            };
+
+            let link = graph::Link::new();
+            link.set_output_port(Some(&output_port));
+            link.set_input_port(Some(&input_port));
+            link.set_active(active);
+
+            items.insert(id, link.clone().upcast());
+
+            // Update graph to contain the new link.
+            self.graph
+                .get()
+                .expect("graph should be set")
+                .add_link(link);
+        }
+
+        fn link_state_changed(&self, id: u32, active: bool) {
+            log::info!(
+                "Link state changed: Link (id={id}) is now {}",
+                if active { "active" } else { "inactive" }
+            );
+
+            let items = self.items.borrow();
+
+            let Some(link) = items.get(&id) else {
+                log::warn!("Link state changed on unknown link (id={id})");
+                return;
+            };
+            let Some(link) = link.dynamic_cast_ref::<graph::Link>() else {
+                log::warn!("Graph Manager item under link id {id} is not a link");
+                return;
+            };
+
+            link.set_active(active);
+        }
+
+        // Toggle a link between the two specified ports on the remote pipewire server.
+        fn toggle_link(&self, port_from: u32, port_to: u32) {
+            let sender = self.pw_sender.get().expect("pw_sender shoud be set");
+            sender
+                .send(crate::GtkMessage::ToggleLink { port_from, port_to })
+                .expect("Failed to send message");
+        }
+
+        /// Remove the link with the specified id from the view.
+        fn remove_link(&self, id: u32) {
+            log::info!("Removing link from graph: id {}", id);
+
+            let Some(link) = self.items.borrow_mut().remove(&id) else {
+                log::warn!("Unknown Link (id={id}) removed from graph");
+                return;
+            };
+            let Ok(link) = link.dynamic_cast::<graph::Link>() else {
+                log::warn!("Graph Manager item under link id {id} is not a link");
+                return;
+            };
+
+            self.obj().graph().remove_link(&link);
+        }
+    }
+}
+
+glib::wrapper! {
+    pub struct GraphManager(ObjectSubclass<imp::GraphManager>);
+}
+
+impl GraphManager {
+    pub fn new(
+        graph: &GraphView,
+        sender: PwSender<GtkMessage>,
+        receiver: glib::Receiver<PipewireMessage>,
+    ) -> Self {
+        let res: Self = glib::Object::builder().property("graph", graph).build();
+
+        res.imp().attach_receiver(receiver);
+        assert!(
+            res.imp().pw_sender.set(sender).is_ok(),
+            "Should be able to set pw_sender)"
+        );
+
+        res
+    }
+}

src/main.rs

@@ -1,16 +1,30 @@
-mod application;
+// Copyright 2021 Tom A. Wagner <tom.a.wagner@protonmail.com>
-mod pipewire_connection;
+//
-mod view;
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 3 as published by
+// the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// SPDX-License-Identifier: GPL-3.0-only
 
-use gtk::{
+mod application;
-    glib::{self, PRIORITY_DEFAULT},
+mod graph_manager;
-    prelude::*,
+mod pipewire_connection;
-};
+mod ui;
+
+use gtk::prelude::*;
 use pipewire::spa::Direction;
 
 /// Messages sent by the GTK thread to notify the pipewire thread.
 #[derive(Debug, Clone)]
-enum GtkMessage {
+pub enum GtkMessage {
     /// Toggle a link between the two specified ports.
     ToggleLink { port_from: u32, port_to: u32 },
     /// Quit the event loop and let the thread finish.
@@ -19,10 +33,11 @@ enum GtkMessage {
 
 /// Messages sent by the pipewire thread to notify the GTK thread.
 #[derive(Debug, Clone)]
-enum PipewireMessage {
+pub enum PipewireMessage {
     NodeAdded {
         id: u32,
         name: String,
+        node_type: Option<NodeType>,
     },
     PortAdded {
         id: u32,
@@ -33,10 +48,13 @@ enum PipewireMessage {
     },
     LinkAdded {
         id: u32,
-        node_from: u32,
         port_from: u32,
-        node_to: u32,
         port_to: u32,
+        active: bool,
+    },
+    LinkStateChanged {
+        id: u32,
+        active: bool,
     },
     NodeRemoved {
         id: u32,
@@ -50,6 +68,12 @@ enum PipewireMessage {
     },
 }
 
+#[derive(Debug, Clone)]
+pub enum NodeType {
+    Input,
+    Output,
+}
+
 #[derive(Debug, Copy, Clone)]
 pub enum MediaType {
     Audio,
@@ -65,8 +89,20 @@ pub struct PipewireLink {
     pub port_to: u32,
 }
 
+static GLIB_LOGGER: glib::GlibLogger = glib::GlibLogger::new(
+    glib::GlibLoggerFormat::Structured,
+    glib::GlibLoggerDomain::CrateTarget,
+);
+
+fn init_glib_logger() {
+    log::set_logger(&GLIB_LOGGER).expect("Failed to set logger");
+
+    // Glib does not have a "Trace" log level, so only print messages "Debug" or higher priority.
+    log::set_max_level(log::LevelFilter::Debug);
+}
+
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    env_logger::init();
+    init_glib_logger();
     gtk::init()?;
 
     // Aquire main context so that we can attach the gtk channel later.
@@ -74,7 +110,8 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     let _guard = ctx.acquire().unwrap();
 
     // Start the pipewire thread with channels in both directions.
-    let (gtk_sender, gtk_receiver) = glib::MainContext::channel(PRIORITY_DEFAULT);
+
+    let (gtk_sender, gtk_receiver) = glib::MainContext::channel(glib::Priority::DEFAULT);
     let (pw_sender, pw_receiver) = pipewire::channel::channel();
     let pw_thread =
         std::thread::spawn(move || pipewire_connection::thread_main(gtk_sender, pw_receiver));

src/meson.build

@@ -0,0 +1,31 @@
+cargo_options = [ '--manifest-path', meson.project_source_root() / 'Cargo.toml' ]
+cargo_options += [ '--target-dir', meson.project_build_root() / 'src' ]
+
+if get_option('profile') == 'default'
+  cargo_options += [ '--release' ]
+  rust_target = 'release'
+  message('Building in release mode')
+else
+  rust_target = 'debug'
+  message('Building in debug mode')
+endif
+
+cargo_env = [ 'CARGO_HOME=' + meson.project_build_root() / 'cargo-home' ]
+
+custom_target(
+  'cargo-build',
+  build_by_default: true,
+  build_always_stale: true,
+  output: meson.project_name(),
+  console: true,
+  install: true,
+  install_dir: bindir,
+  command: [
+    'env',
+    cargo_env,
+    cargo, 'build',
+    cargo_options,
+    '&&',
+    'cp', 'src' / rust_target / meson.project_name(), '@OUTPUT@',
+  ],
+)

src/pipewire_connection.rs

@@ -1,3 +1,19 @@
+// Copyright 2021 Tom A. Wagner <tom.a.wagner@protonmail.com>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 3 as published by
+// the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// SPDX-License-Identifier: GPL-3.0-only
+
 mod state;
 
 use std::{cell::RefCell, collections::HashMap, rc::Rc};
@@ -5,7 +21,7 @@ use std::{cell::RefCell, collections::HashMap, rc::Rc};
 use gtk::glib::{self, clone};
 use log::{debug, info, warn};
 use pipewire::{
-    link::{Link, LinkListener},
+    link::{Link, LinkChangeMask, LinkListener, LinkState},
     prelude::*,
     properties,
     registry::{GlobalObject, Registry},
@@ -14,7 +30,7 @@ use pipewire::{
     Context, Core, MainLoop,
 };
 
-use crate::{GtkMessage, MediaType, PipewireMessage};
+use crate::{GtkMessage, MediaType, NodeType, PipewireMessage};
 use state::{Item, State};
 
 enum ProxyItem {
@@ -93,27 +109,45 @@ fn handle_node(
     // Get the nicest possible name for the node, using a fallback chain of possible name attributes.
     let name = String::from(
         props
-            .get("node.nick")
+            .get("node.description")
-            .or_else(|| props.get("node.description"))
+            .or_else(|| props.get("node.nick"))
             .or_else(|| props.get("node.name"))
             .unwrap_or_default(),
     );
 
     // FIXME: Instead of checking these props, the "EnumFormat" parameter should be checked instead.
-    let media_type = props
+    let media_type = props.get("media.class").and_then(|class| {
-        .get("media.class")
+        if class.contains("Audio") {
-        .map(|class| {
+            Some(MediaType::Audio)
-            if class.contains("Audio") {
+        } else if class.contains("Video") {
-                Some(MediaType::Audio)
+            Some(MediaType::Video)
-            } else if class.contains("Video") {
+        } else if class.contains("Midi") {
-                Some(MediaType::Video)
+            Some(MediaType::Midi)
-            } else if class.contains("Midi") {
+        } else {
-                Some(MediaType::Midi)
+            None
-            } else {
+        }
+    });
+
+    let media_class = |class: &str| {
+        if class.contains("Sink") || class.contains("Input") {
+            Some(NodeType::Input)
+        } else if class.contains("Source") || class.contains("Output") {
+            Some(NodeType::Output)
+        } else {
+            None
+        }
+    };
+
+    let node_type = props
+        .get("media.category")
+        .and_then(|class| {
+            if class.contains("Duplex") {
                 None
+            } else {
+                props.get("media.class").and_then(media_class)
             }
         })
-        .flatten();
+        .or_else(|| props.get("media.class").and_then(media_class));
 
     state.borrow_mut().insert(
         node.id,
@@ -124,7 +158,11 @@ fn handle_node(
     );
 
     sender
-        .send(PipewireMessage::NodeAdded { id: node.id, name })
+        .send(PipewireMessage::NodeAdded {
+            id: node.id,
+            name,
+            node_type,
+        })
         .expect("Failed to send message");
 }
 
@@ -196,12 +234,16 @@ fn handle_link(
             let mut state = state.borrow_mut();
             if let Some(Item::Link { .. }) = state.get(id) {
                 // Info was an update - figure out if we should notify the gtk thread
-                // TODO
+                if info.change_mask().contains(LinkChangeMask::STATE) {
+                    sender.send(PipewireMessage::LinkStateChanged {
+                        id,
+                        active: matches!(info.state(), LinkState::Active)
+                    }).expect("Failed to send message");
+                }
+                // TODO -- check other values that might have changed
             } else {
                 // First time we get info. We can now notify the gtk thread of a new link.
-                let node_from = info.output_node_id();
                 let port_from = info.output_port_id();
-                let node_to = info.input_node_id();
                 let port_to = info.input_port_id();
 
                 state.insert(id, Item::Link {
@@ -210,10 +252,9 @@ fn handle_link(
 
                 sender.send(PipewireMessage::LinkAdded {
                     id,
-                    node_from,
                     port_from,
-                    node_to,
+                    port_to,
-                    port_to
+                    active: matches!(info.state(), LinkState::Active)
                 }).expect(
                     "Failed to send message"
                 );

src/pipewire_connection/state.rs

@@ -1,3 +1,19 @@
+// Copyright 2021 Tom A. Wagner <tom.a.wagner@protonmail.com>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 3 as published by
+// the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// SPDX-License-Identifier: GPL-3.0-only
+
 use std::collections::HashMap;
 
 use crate::MediaType;
@@ -34,7 +50,7 @@ pub(super) struct State {
 impl State {
     /// Create a new, empty state.
     pub fn new() -> Self {
-        Default::default()
+        Self::default()
     }
 
     /// Add a new item under the specified id.

src/style.css

@@ -1,14 +1,40 @@
+/* Copyright 2021 Tom A. Wagner <tom.a.wagner@protonmail.com>
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License version 3 as published by
+   the Free Software Foundation.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+   SPDX-License-Identifier: GPL-3.0-only
+*/
+
+@define-color audio rgb(50,100,240);
+@define-color video rgb(200,200,0);
+@define-color midi rgb(200,0,50);
+@define-color graphview-link #808080;
+
 .audio {
-    background: rgb(50,100,240);
+    background: @audio;
     color: black;
 }
 
 .video {
-    background: rgb(200,200,0);
+    background: @video;
     color: black;
 }
 
 .midi {
-    background: rgb(200,0,50);
+    background: @midi;
     color: black;
 }
+
+graphview {
+    background-color: @text_view_bg;
+}

src/ui/graph/graph_view.rs

@@ -0,0 +1,836 @@
+// Copyright 2021 Tom A. Wagner <tom.a.wagner@protonmail.com>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 3 as published by
+// the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// SPDX-License-Identifier: GPL-3.0-only
+
+use gtk::{
+    cairo, gio,
+    glib::{self, clone},
+    graphene::{self, Point},
+    gsk,
+    prelude::*,
+    subclass::prelude::*,
+};
+
+use std::cmp::Ordering;
+
+use super::{Link, Node, Port};
+use crate::NodeType;
+
+const CANVAS_SIZE: f64 = 5000.0;
+
+mod imp {
+    use super::*;
+
+    use std::cell::{Cell, RefCell};
+    use std::collections::{HashMap, HashSet};
+
+    use gtk::{
+        gdk::{self, RGBA},
+        graphene::Rect,
+        gsk::ColorStop,
+    };
+    use log::warn;
+    use once_cell::sync::Lazy;
+    use pipewire::spa::Direction;
+
+    pub struct DragState {
+        node: glib::WeakRef<Node>,
+        /// This stores the offset of the pointer to the origin of the node,
+        /// so that we can keep the pointer over the same position when moving the node
+        ///
+        /// The offset is normalized to the default zoom-level of 1.0.
+        offset: Point,
+    }
+
+    pub struct GraphView {
+        /// Stores nodes and their positions.
+        pub(super) nodes: RefCell<HashMap<Node, Point>>,
+        /// Stores the links and whether they are currently active.
+        pub(super) links: RefCell<HashSet<Link>>,
+
+        // Properties for zooming and scrolling the hraph
+        pub hadjustment: RefCell<Option<gtk::Adjustment>>,
+        pub vadjustment: RefCell<Option<gtk::Adjustment>>,
+        pub zoom_factor: Cell<f64>,
+
+        /// This keeps track of an ongoing node drag operation.
+        pub dragged_node: RefCell<Option<DragState>>,
+
+        // These keep track of an ongoing port drag operation
+        pub dragged_port: glib::WeakRef<Port>,
+        pub port_drag_cursor: Cell<Point>,
+
+        // Memorized data for an in-progress zoom gesture
+        pub zoom_gesture_initial_zoom: Cell<Option<f64>>,
+        pub zoom_gesture_anchor: Cell<Option<(f64, f64)>>,
+    }
+
+    impl Default for GraphView {
+        fn default() -> Self {
+            Self {
+                nodes: Default::default(),
+                links: Default::default(),
+                hadjustment: Default::default(),
+                vadjustment: Default::default(),
+                zoom_factor: Default::default(),
+                dragged_node: Default::default(),
+                dragged_port: Default::default(),
+                port_drag_cursor: Cell::new(Point::new(0.0, 0.0)),
+                zoom_gesture_initial_zoom: Default::default(),
+                zoom_gesture_anchor: Default::default(),
+            }
+        }
+    }
+
+    #[glib::object_subclass]
+    impl ObjectSubclass for GraphView {
+        const NAME: &'static str = "GraphView";
+        type Type = super::GraphView;
+        type ParentType = gtk::Widget;
+        type Interfaces = (gtk::Scrollable,);
+
+        fn class_init(klass: &mut Self::Class) {
+            klass.set_css_name("graphview");
+        }
+    }
+
+    impl ObjectImpl for GraphView {
+        fn constructed(&self) {
+            self.parent_constructed();
+
+            self.obj().set_overflow(gtk::Overflow::Hidden);
+
+            self.setup_node_dragging();
+            self.setup_port_drag_and_drop();
+            self.setup_scroll_zooming();
+            self.setup_zoom_gesture();
+        }
+
+        fn dispose(&self) {
+            self.nodes
+                .borrow()
+                .iter()
+                .for_each(|(node, _)| node.unparent())
+        }
+
+        fn properties() -> &'static [glib::ParamSpec] {
+            static PROPERTIES: Lazy<Vec<glib::ParamSpec>> = Lazy::new(|| {
+                vec![
+                    glib::ParamSpecOverride::for_interface::<gtk::Scrollable>("hadjustment"),
+                    glib::ParamSpecOverride::for_interface::<gtk::Scrollable>("vadjustment"),
+                    glib::ParamSpecOverride::for_interface::<gtk::Scrollable>("hscroll-policy"),
+                    glib::ParamSpecOverride::for_interface::<gtk::Scrollable>("vscroll-policy"),
+                    glib::ParamSpecDouble::builder("zoom-factor")
+                        .minimum(0.3)
+                        .maximum(4.0)
+                        .default_value(1.0)
+                        .flags(glib::ParamFlags::CONSTRUCT | glib::ParamFlags::READWRITE)
+                        .build(),
+                ]
+            });
+
+            PROPERTIES.as_ref()
+        }
+
+        fn property(&self, _id: usize, pspec: &glib::ParamSpec) -> glib::Value {
+            match pspec.name() {
+                "hadjustment" => self.hadjustment.borrow().to_value(),
+                "vadjustment" => self.vadjustment.borrow().to_value(),
+                "hscroll-policy" | "vscroll-policy" => gtk::ScrollablePolicy::Natural.to_value(),
+                "zoom-factor" => self.zoom_factor.get().to_value(),
+                _ => unimplemented!(),
+            }
+        }
+
+        fn set_property(&self, _id: usize, value: &glib::Value, pspec: &glib::ParamSpec) {
+            let obj = self.obj();
+
+            match pspec.name() {
+                "hadjustment" => {
+                    self.set_adjustment(&obj, value.get().ok(), gtk::Orientation::Horizontal)
+                }
+                "vadjustment" => {
+                    self.set_adjustment(&obj, value.get().ok(), gtk::Orientation::Vertical)
+                }
+                "hscroll-policy" | "vscroll-policy" => {}
+                "zoom-factor" => {
+                    self.zoom_factor.set(value.get().unwrap());
+                    obj.queue_allocate();
+                }
+                _ => unimplemented!(),
+            }
+        }
+    }
+
+    impl WidgetImpl for GraphView {
+        fn size_allocate(&self, _width: i32, _height: i32, baseline: i32) {
+            let widget = &*self.obj();
+
+            for (node, point) in self.nodes.borrow().iter() {
+                let (_, natural_size) = node.preferred_size();
+
+                let transform = self
+                    .canvas_space_to_screen_space_transform()
+                    .translate(point);
+
+                node.allocate(
+                    natural_size.width(),
+                    natural_size.height(),
+                    baseline,
+                    Some(transform),
+                );
+            }
+
+            if let Some(ref hadjustment) = *self.hadjustment.borrow() {
+                self.set_adjustment_values(widget, hadjustment, gtk::Orientation::Horizontal);
+            }
+            if let Some(ref vadjustment) = *self.vadjustment.borrow() {
+                self.set_adjustment_values(widget, vadjustment, gtk::Orientation::Vertical);
+            }
+        }
+
+        fn snapshot(&self, snapshot: &gtk::Snapshot) {
+            let widget = &*self.obj();
+            let alloc = widget.allocation();
+
+            self.snapshot_background(widget, snapshot);
+
+            // Draw all visible children
+            self.nodes
+                .borrow()
+                .iter()
+                // Cull nodes from rendering when they are outside the visible canvas area
+                .filter(|(node, _)| alloc.intersect(&node.allocation()).is_some())
+                .for_each(|(node, _)| widget.snapshot_child(node, snapshot));
+
+            self.snapshot_links(widget, snapshot);
+        }
+    }
+
+    impl ScrollableImpl for GraphView {}
+
+    impl GraphView {
+        /// Returns a [`gsk::Transform`] matrix that can translate from canvas space to screen space.
+        ///
+        /// Canvas space is non-zoomed, and (0, 0) is fixed at the middle of the graph. \
+        /// Screen space is zoomed and adjusted for scrolling, (0, 0) is at the top-left corner of the window.
+        ///
+        /// This is the inverted form of [`Self::screen_space_to_canvas_space_transform()`].
+        fn canvas_space_to_screen_space_transform(&self) -> gsk::Transform {
+            let hadj = self.hadjustment.borrow().as_ref().unwrap().value();
+            let vadj = self.vadjustment.borrow().as_ref().unwrap().value();
+            let zoom_factor = self.zoom_factor.get();
+
+            gsk::Transform::new()
+                .translate(&Point::new(-hadj as f32, -vadj as f32))
+                .scale(zoom_factor as f32, zoom_factor as f32)
+        }
+
+        /// Returns a [`gsk::Transform`] matrix that can translate from screen space to canvas space.
+        ///
+        /// This is the inverted form of [`Self::canvas_space_to_screen_space_transform()`], see that function for a more detailed explantion.
+        fn screen_space_to_canvas_space_transform(&self) -> gsk::Transform {
+            self.canvas_space_to_screen_space_transform()
+                .invert()
+                .unwrap()
+        }
+
+        fn setup_node_dragging(&self) {
+            let drag_controller = gtk::GestureDrag::new();
+
+            drag_controller.connect_drag_begin(|drag_controller, x, y| {
+                let widget = drag_controller
+                    .widget()
+                    .dynamic_cast::<super::GraphView>()
+                    .expect("drag-begin event is not on the GraphView");
+                let mut dragged_node = widget.imp().dragged_node.borrow_mut();
+
+                // pick() should at least return the widget itself.
+                let target = widget
+                    .pick(x, y, gtk::PickFlags::DEFAULT)
+                    .expect("drag-begin pick() did not return a widget");
+                *dragged_node = if target.ancestor(Port::static_type()).is_some() {
+                    // The user targeted a port, so the dragging should be handled by the Port
+                    // component instead of here.
+                    None
+                } else if let Some(target) = target.ancestor(Node::static_type()) {
+                    // The user targeted a Node without targeting a specific Port.
+                    // Drag the Node around the screen.
+                    let node = target.dynamic_cast_ref::<Node>().unwrap();
+
+                    let Some(canvas_node_pos) = widget.node_position(node) else { return };
+                    let canvas_cursor_pos = widget
+                        .imp()
+                        .screen_space_to_canvas_space_transform()
+                        .transform_point(&Point::new(x as f32, y as f32));
+
+                    Some(DragState {
+                        node: node.clone().downgrade(),
+                        offset: Point::new(
+                            canvas_cursor_pos.x() - canvas_node_pos.x(),
+                            canvas_cursor_pos.y() - canvas_node_pos.y(),
+                        ),
+                    })
+                } else {
+                    None
+                }
+            });
+            drag_controller.connect_drag_update(|drag_controller, x, y| {
+                let widget = drag_controller
+                    .widget()
+                    .dynamic_cast::<super::GraphView>()
+                    .expect("drag-update event is not on the GraphView");
+                let dragged_node = widget.imp().dragged_node.borrow();
+                let Some(DragState { node, offset }) = dragged_node.as_ref() else { return };
+                let Some(node) = node.upgrade() else { return };
+
+                let (start_x, start_y) = drag_controller
+                    .start_point()
+                    .expect("Drag has no start point");
+
+                let onscreen_node_origin = Point::new((start_x + x) as f32, (start_y + y) as f32);
+                let transform = widget.imp().screen_space_to_canvas_space_transform();
+                let canvas_node_origin = transform.transform_point(&onscreen_node_origin);
+
+                widget.move_node(
+                    &node,
+                    &Point::new(
+                        canvas_node_origin.x() - offset.x(),
+                        canvas_node_origin.y() - offset.y(),
+                    ),
+                );
+            });
+            self.obj().add_controller(drag_controller);
+        }
+
+        fn setup_port_drag_and_drop(&self) {
+            let controller = gtk::DropControllerMotion::new();
+
+            controller.connect_enter(|controller, x, y| {
+                let graph = controller
+                    .widget()
+                    .downcast::<super::GraphView>()
+                    .expect("Widget should be a graphview");
+
+                graph.imp().port_drag_enter(controller, x, y)
+            });
+
+            controller.connect_motion(|controller, x, y| {
+                let graph = controller
+                    .widget()
+                    .downcast::<super::GraphView>()
+                    .expect("Widget should be a graphview");
+
+                graph.imp().port_drag_motion(x, y)
+            });
+
+            controller.connect_leave(|controller| {
+                let graph = controller
+                    .widget()
+                    .downcast::<super::GraphView>()
+                    .expect("Widget should be a graphview");
+
+                graph.imp().port_drag_leave()
+            });
+
+            self.obj().add_controller(controller);
+        }
+
+        fn port_drag_enter(&self, controller: &gtk::DropControllerMotion, x: f64, y: f64) {
+            let Some(drop) = controller.drop() else {
+                return;
+            };
+
+            self.port_drag_cursor.set(Point::new(x as f32, y as f32));
+
+            drop.read_value_async(
+                Port::static_type(),
+                glib::Priority::DEFAULT,
+                Option::<&gio::Cancellable>::None,
+                clone!(@weak self as imp => move|value| {
+                    let Ok(value) = value else {
+                        return;
+                    };
+                    let port: &Port = value.get().expect("Value should contain a port");
+
+                    imp.dragged_port.set(Some(port));
+                }),
+            );
+
+            self.obj().queue_draw();
+        }
+
+        fn port_drag_motion(&self, x: f64, y: f64) {
+            if self.dragged_port.upgrade().is_some() {
+                self.port_drag_cursor.set(Point::new(x as f32, y as f32));
+
+                self.obj().queue_draw();
+            }
+        }
+
+        fn port_drag_leave(&self) {
+            if self.dragged_port.upgrade().is_some() {
+                self.dragged_port.set(None);
+                self.obj().queue_draw();
+            }
+        }
+
+        fn setup_scroll_zooming(&self) {
+            // We're only interested in the vertical axis, but for devices like touchpads,
+            // not capturing a small accidental horizontal move may cause the scroll to be disrupted if a widget
+            // higher up captures it instead.
+            let scroll_controller =
+                gtk::EventControllerScroll::new(gtk::EventControllerScrollFlags::BOTH_AXES);
+
+            scroll_controller.connect_scroll(|eventcontroller, _, delta_y| {
+                let event = eventcontroller.current_event().unwrap(); // We are inside the event handler, so it must have an event
+
+                if event
+                    .modifier_state()
+                    .contains(gdk::ModifierType::CONTROL_MASK)
+                {
+                    let widget = eventcontroller
+                        .widget()
+                        .downcast::<super::GraphView>()
+                        .unwrap();
+                    widget.set_zoom_factor(widget.zoom_factor() + (0.1 * -delta_y), None);
+
+                    glib::Propagation::Stop
+                } else {
+                    glib::Propagation::Proceed
+                }
+            });
+            self.obj().add_controller(scroll_controller);
+        }
+
+        fn setup_zoom_gesture(&self) {
+            let zoom_gesture = gtk::GestureZoom::new();
+            zoom_gesture.connect_begin(|gesture, _| {
+                let widget = gesture.widget().downcast::<super::GraphView>().unwrap();
+
+                widget
+                    .imp()
+                    .zoom_gesture_initial_zoom
+                    .set(Some(widget.zoom_factor()));
+                widget
+                    .imp()
+                    .zoom_gesture_anchor
+                    .set(gesture.bounding_box_center());
+            });
+            zoom_gesture.connect_scale_changed(move |gesture, delta| {
+                let widget = gesture.widget().downcast::<super::GraphView>().unwrap();
+
+                let initial_zoom = widget
+                    .imp()
+                    .zoom_gesture_initial_zoom
+                    .get()
+                    .expect("Initial zoom not set during zoom gesture");
+
+                widget.set_zoom_factor(initial_zoom * delta, gesture.bounding_box_center());
+            });
+            self.obj().add_controller(zoom_gesture);
+        }
+
+        fn snapshot_background(&self, widget: &super::GraphView, snapshot: &gtk::Snapshot) {
+            // Grid size and line width during neutral zoom (factor 1.0).
+            const NORMAL_GRID_SIZE: f32 = 20.0;
+            const NORMAL_GRID_LINE_WIDTH: f32 = 1.0;
+
+            let zoom_factor = self.zoom_factor.get();
+            let grid_size = NORMAL_GRID_SIZE * zoom_factor as f32;
+            let grid_line_width = NORMAL_GRID_LINE_WIDTH * zoom_factor as f32;
+
+            let alloc = widget.allocation();
+
+            // We need to offset the lines between 0 and (excluding) `grid_size` so the grid moves with
+            // the rest of the view when scrolling.
+            // The offset is rounded so the grid is always aligned to a row of pixels.
+            let hadj = self
+                .hadjustment
+                .borrow()
+                .as_ref()
+                .map(|hadjustment| hadjustment.value())
+                .unwrap_or(0.0);
+            let hoffset = (grid_size - (hadj as f32 % grid_size)) % grid_size;
+            let vadj = self
+                .vadjustment
+                .borrow()
+                .as_ref()
+                .map(|vadjustment| vadjustment.value())
+                .unwrap_or(0.0);
+            let voffset = (grid_size - (vadj as f32 % grid_size)) % grid_size;
+
+            snapshot.push_repeat(
+                &Rect::new(0.0, 0.0, alloc.width() as f32, alloc.height() as f32),
+                Some(&Rect::new(0.0, voffset, alloc.width() as f32, grid_size)),
+            );
+            let grid_color = RGBA::new(0.137, 0.137, 0.137, 1.0);
+            snapshot.append_linear_gradient(
+                &Rect::new(0.0, voffset, alloc.width() as f32, grid_line_width),
+                &Point::new(0.0, 0.0),
+                &Point::new(alloc.width() as f32, 0.0),
+                &[
+                    ColorStop::new(0.0, grid_color),
+                    ColorStop::new(1.0, grid_color),
+                ],
+            );
+            snapshot.pop();
+
+            snapshot.push_repeat(
+                &Rect::new(0.0, 0.0, alloc.width() as f32, alloc.height() as f32),
+                Some(&Rect::new(hoffset, 0.0, grid_size, alloc.height() as f32)),
+            );
+            snapshot.append_linear_gradient(
+                &Rect::new(hoffset, 0.0, grid_line_width, alloc.height() as f32),
+                &Point::new(0.0, 0.0),
+                &Point::new(0.0, alloc.height() as f32),
+                &[
+                    ColorStop::new(0.0, grid_color),
+                    ColorStop::new(1.0, grid_color),
+                ],
+            );
+            snapshot.pop();
+        }
+
+        fn draw_link(
+            &self,
+            link_cr: &cairo::Context,
+            output_anchor: &Point,
+            input_anchor: &Point,
+            active: bool,
+        ) {
+            let output_x: f64 = output_anchor.x().into();
+            let output_y: f64 = output_anchor.y().into();
+            let input_x: f64 = input_anchor.x().into();
+            let input_y: f64 = input_anchor.y().into();
+
+            // Use dashed line for inactive links, full line otherwise.
+            if active {
+                link_cr.set_dash(&[], 0.0);
+            } else {
+                link_cr.set_dash(&[10.0, 5.0], 0.0);
+            }
+
+            // If the output port is farther right than the input port and they have
+            // a similar y coordinate, apply a y offset to the control points
+            // so that the curve sticks out a bit.
+            let y_control_offset = if output_x > input_x {
+                f64::max(0.0, 25.0 - (output_y - input_y).abs())
+            } else {
+                0.0
+            };
+
+            // Place curve control offset by half the x distance between the two points.
+            // This makes the curve scale well for varying distances between the two ports,
+            // especially when the output port is farther right than the input port.
+            let half_x_dist = f64::abs(output_x - input_x) / 2.0;
+            link_cr.move_to(output_x, output_y);
+            link_cr.curve_to(
+                output_x + half_x_dist,
+                output_y - y_control_offset,
+                input_x - half_x_dist,
+                input_y - y_control_offset,
+                input_x,
+                input_y,
+            );
+
+            if let Err(e) = link_cr.stroke() {
+                warn!("Failed to draw graphview links: {}", e);
+            };
+        }
+
+        fn draw_dragged_link(&self, port: &Port, link_cr: &cairo::Context) {
+            let Some(port_anchor) = port.compute_point(&*self.obj(), &port.link_anchor()) else {
+                return;
+            };
+            let drag_cursor = self.port_drag_cursor.get();
+
+            /* If we can find a linkable port under the cursor, link to its anchor,
+             * otherwise link to the mouse cursor */
+            let picked_port = self
+                .obj()
+                .pick(
+                    drag_cursor.x().into(),
+                    drag_cursor.y().into(),
+                    gtk::PickFlags::DEFAULT,
+                )
+                .and_then(|widget| widget.ancestor(Port::static_type()).and_downcast::<Port>())
+                .filter(|picked_port| port.is_linkable_to(picked_port));
+            let picked_port_anchor = picked_port.and_then(|picked_port| {
+                picked_port.compute_point(&*self.obj(), &picked_port.link_anchor())
+            });
+            let other_anchor = picked_port_anchor.unwrap_or(drag_cursor);
+
+            let (output_anchor, input_anchor) = match port.direction() {
+                Direction::Output => (&port_anchor, &other_anchor),
+                Direction::Input => (&other_anchor, &port_anchor),
+                _ => unreachable!(),
+            };
+
+            self.draw_link(link_cr, output_anchor, input_anchor, false);
+        }
+
+        fn snapshot_links(&self, widget: &super::GraphView, snapshot: &gtk::Snapshot) {
+            let alloc = widget.allocation();
+
+            let link_cr = snapshot.append_cairo(&graphene::Rect::new(
+                0.0,
+                0.0,
+                alloc.width() as f32,
+                alloc.height() as f32,
+            ));
+
+            link_cr.set_line_width(2.0 * self.zoom_factor.get());
+
+            let rgba = widget
+                .style_context()
+                .lookup_color("graphview-link")
+                .unwrap_or(gtk::gdk::RGBA::BLACK);
+
+            link_cr.set_source_rgba(
+                rgba.red().into(),
+                rgba.green().into(),
+                rgba.blue().into(),
+                rgba.alpha().into(),
+            );
+
+            for link in self.links.borrow().iter() {
+                // TODO: Do not draw links when they are outside the view
+                let Some((output_anchor, input_anchor)) = self.get_link_coordinates(link) else {
+                    warn!("Could not get allocation of ports of link: {:?}", link);
+                    continue;
+                };
+
+                self.draw_link(&link_cr, &output_anchor, &input_anchor, link.active());
+            }
+
+            if let Some(port) = self.dragged_port.upgrade() {
+                self.draw_dragged_link(&port, &link_cr);
+            }
+        }
+
+        /// Get coordinates for the drawn link to start at and to end at.
+        ///
+        /// # Returns
+        /// `Some((output_anchor, input_anchor))` if all objects the links refers to exist as widgets
+        /// and those widgets are contained by the graph.
+        ///
+        /// The returned coordinates are in screen-space of the graph.
+        fn get_link_coordinates(&self, link: &Link) -> Option<(graphene::Point, graphene::Point)> {
+            let widget = &*self.obj();
+
+            let output_port = link.output_port()?;
+            let output_anchor = output_port.compute_point(widget, &output_port.link_anchor())?;
+
+            let input_port = link.input_port()?;
+            let input_anchor = input_port.compute_point(widget, &input_port.link_anchor())?;
+
+            Some((output_anchor, input_anchor))
+        }
+
+        fn set_adjustment(
+            &self,
+            obj: &super::GraphView,
+            adjustment: Option<&gtk::Adjustment>,
+            orientation: gtk::Orientation,
+        ) {
+            match orientation {
+                gtk::Orientation::Horizontal => {
+                    *self.hadjustment.borrow_mut() = adjustment.cloned()
+                }
+                gtk::Orientation::Vertical => *self.vadjustment.borrow_mut() = adjustment.cloned(),
+                _ => unimplemented!(),
+            }
+
+            if let Some(adjustment) = adjustment {
+                adjustment
+                    .connect_value_changed(clone!(@weak obj => move |_|  obj.queue_allocate() ));
+            }
+        }
+
+        fn set_adjustment_values(
+            &self,
+            obj: &super::GraphView,
+            adjustment: &gtk::Adjustment,
+            orientation: gtk::Orientation,
+        ) {
+            let size = match orientation {
+                gtk::Orientation::Horizontal => obj.width(),
+                gtk::Orientation::Vertical => obj.height(),
+                _ => unimplemented!(),
+            };
+            let zoom_factor = self.zoom_factor.get();
+
+            adjustment.configure(
+                adjustment.value(),
+                -(CANVAS_SIZE / 2.0) * zoom_factor,
+                (CANVAS_SIZE / 2.0) * zoom_factor,
+                (f64::from(size) * 0.1) * zoom_factor,
+                (f64::from(size) * 0.9) * zoom_factor,
+                f64::from(size) * zoom_factor,
+            );
+        }
+    }
+}
+
+glib::wrapper! {
+    pub struct GraphView(ObjectSubclass<imp::GraphView>)
+        @extends gtk::Widget;
+}
+
+impl GraphView {
+    pub const ZOOM_MIN: f64 = 0.3;
+    pub const ZOOM_MAX: f64 = 4.0;
+
+    pub fn new() -> Self {
+        glib::Object::new()
+    }
+
+    pub fn zoom_factor(&self) -> f64 {
+        self.property("zoom-factor")
+    }
+
+    /// Set the scale factor.
+    ///
+    /// A factor of 1.0 is equivalent to 100% zoom, 0.5 to 50% zoom etc.
+    ///
+    /// An optional anchor (in canvas-space coordinates) can be specified, which will be used as the center of the zoom,
+    /// so that its position stays fixed.
+    /// If no anchor is specified, the middle of the screen is used instead.
+    ///
+    /// Note that the zoom level is [clamped](`f64::clamp`) to between 30% and 300%.
+    /// See [`Self::ZOOM_MIN`] and [`Self::ZOOM_MAX`].
+    pub fn set_zoom_factor(&self, zoom_factor: f64, anchor: Option<(f64, f64)>) {
+        let zoom_factor = zoom_factor.clamp(Self::ZOOM_MIN, Self::ZOOM_MAX);
+
+        let (anchor_x_screen, anchor_y_screen) = anchor.unwrap_or_else(|| {
+            (
+                self.allocation().width() as f64 / 2.0,
+                self.allocation().height() as f64 / 2.0,
+            )
+        });
+
+        let old_zoom = self.imp().zoom_factor.get();
+        let hadjustment_ref = self.imp().hadjustment.borrow();
+        let vadjustment_ref = self.imp().vadjustment.borrow();
+        let hadjustment = hadjustment_ref.as_ref().unwrap();
+        let vadjustment = vadjustment_ref.as_ref().unwrap();
+
+        let x_total = (anchor_x_screen + hadjustment.value()) / old_zoom;
+        let y_total = (anchor_y_screen + vadjustment.value()) / old_zoom;
+
+        let new_hadjustment = x_total * zoom_factor - anchor_x_screen;
+        let new_vadjustment = y_total * zoom_factor - anchor_y_screen;
+
+        hadjustment.set_value(new_hadjustment);
+        vadjustment.set_value(new_vadjustment);
+
+        self.set_property("zoom-factor", zoom_factor);
+    }
+
+    pub fn add_node(&self, node: Node, node_type: Option<NodeType>) {
+        let imp = self.imp();
+        node.set_parent(self);
+
+        // Place widgets in colums of 3, growing down
+        let x = if let Some(node_type) = node_type {
+            match node_type {
+                NodeType::Output => 20.0,
+                NodeType::Input => 820.0,
+            }
+        } else {
+            420.0
+        };
+
+        let y = imp
+            .nodes
+            .borrow()
+            .iter()
+            .map(|node| {
+                // Map nodes to their locations
+                let point = self.node_position(&node.0.clone().upcast()).unwrap();
+                (point.x(), point.y())
+            })
+            .filter(|(x2, _)| {
+                // Only look for other nodes that have a similar x coordinate
+                (x - x2).abs() < 50.0
+            })
+            .max_by(|y1, y2| {
+                // Get max in column
+                y1.partial_cmp(y2).unwrap_or(Ordering::Equal)
+            })
+            .map_or(20_f32, |(_x, y)| y + 120.0);
+
+        imp.nodes.borrow_mut().insert(node, Point::new(x, y));
+    }
+
+    pub fn remove_node(&self, node: &Node) {
+        let mut nodes = self.imp().nodes.borrow_mut();
+
+        if nodes.remove(node).is_some() {
+            node.unparent();
+        } else {
+            log::warn!("Tried to remove non-existant node widget from graph");
+        }
+    }
+
+    pub fn add_link(&self, link: Link) {
+        link.connect_notify_local(
+            Some("active"),
+            glib::clone!(@weak self as graph => move |_, _| {
+                graph.queue_draw();
+            }),
+        );
+        self.imp().links.borrow_mut().insert(link);
+        self.queue_draw();
+    }
+
+    pub fn remove_link(&self, link: &Link) {
+        let mut links = self.imp().links.borrow_mut();
+        links.remove(link);
+
+        self.queue_draw();
+    }
+
+    /// Get the position of the specified node inside the graphview.
+    ///
+    /// The returned position is in canvas-space (non-zoomed, (0, 0) fixed in the middle of the canvas).
+    pub(super) fn node_position(&self, node: &Node) -> Option<Point> {
+        self.imp().nodes.borrow().get(node).copied()
+    }
+
+    pub(super) fn move_node(&self, widget: &Node, point: &Point) {
+        let mut nodes = self.imp().nodes.borrow_mut();
+        let node_point = nodes.get_mut(widget).expect("Node is not on the graph");
+
+        // Clamp the new position to within the graph, so a node can't be moved outside it and be lost.
+        node_point.set_x(point.x().clamp(
+            -(CANVAS_SIZE / 2.0) as f32,
+            (CANVAS_SIZE / 2.0) as f32 - widget.width() as f32,
+        ));
+        node_point.set_y(point.y().clamp(
+            -(CANVAS_SIZE / 2.0) as f32,
+            (CANVAS_SIZE / 2.0) as f32 - widget.height() as f32,
+        ));
+
+        self.queue_allocate();
+    }
+}
+
+impl Default for GraphView {
+    fn default() -> Self {
+        Self::new()
+    }
+}

src/ui/graph/link.rs

@@ -0,0 +1,120 @@
+// Copyright 2021 Tom A. Wagner <tom.a.wagner@protonmail.com>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 3 as published by
+// the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// SPDX-License-Identifier: GPL-3.0-only
+
+use gtk::{glib, prelude::*, subclass::prelude::*};
+
+use super::Port;
+
+mod imp {
+    use super::*;
+
+    use std::cell::Cell;
+
+    use once_cell::sync::Lazy;
+
+    #[derive(Default)]
+    pub struct Link {
+        pub output_port: glib::WeakRef<Port>,
+        pub input_port: glib::WeakRef<Port>,
+        pub active: Cell<bool>,
+    }
+
+    #[glib::object_subclass]
+    impl ObjectSubclass for Link {
+        const NAME: &'static str = "HelvumLink";
+        type Type = super::Link;
+        type ParentType = glib::Object;
+    }
+
+    impl ObjectImpl for Link {
+        fn properties() -> &'static [glib::ParamSpec] {
+            static PROPERTIES: Lazy<Vec<glib::ParamSpec>> = Lazy::new(|| {
+                vec![
+                    glib::ParamSpecObject::builder::<Port>("output-port")
+                        .flags(glib::ParamFlags::READWRITE)
+                        .build(),
+                    glib::ParamSpecObject::builder::<Port>("input-port")
+                        .flags(glib::ParamFlags::READWRITE)
+                        .build(),
+                    glib::ParamSpecBoolean::builder("active")
+                        .default_value(false)
+                        .flags(glib::ParamFlags::READWRITE)
+                        .build(),
+                ]
+            });
+
+            PROPERTIES.as_ref()
+        }
+
+        fn property(&self, _id: usize, pspec: &glib::ParamSpec) -> glib::Value {
+            match pspec.name() {
+                "output-port" => self.output_port.upgrade().to_value(),
+                "input-port" => self.input_port.upgrade().to_value(),
+                "active" => self.active.get().to_value(),
+                _ => unimplemented!(),
+            }
+        }
+
+        fn set_property(&self, _id: usize, value: &glib::Value, pspec: &glib::ParamSpec) {
+            match pspec.name() {
+                "output-port" => self.output_port.set(value.get().unwrap()),
+                "input-port" => self.input_port.set(value.get().unwrap()),
+                "active" => self.active.set(value.get().unwrap()),
+                _ => unimplemented!(),
+            }
+        }
+    }
+}
+
+glib::wrapper! {
+    pub struct Link(ObjectSubclass<imp::Link>);
+}
+
+impl Link {
+    pub fn new() -> Self {
+        glib::Object::new()
+    }
+
+    pub fn output_port(&self) -> Option<Port> {
+        self.property("output-port")
+    }
+
+    pub fn set_output_port(&self, port: Option<&Port>) {
+        self.set_property("output-port", port);
+    }
+
+    pub fn input_port(&self) -> Option<Port> {
+        self.property("input-port")
+    }
+
+    pub fn set_input_port(&self, port: Option<&Port>) {
+        self.set_property("input-port", port);
+    }
+
+    pub fn active(&self) -> bool {
+        self.property("active")
+    }
+
+    pub fn set_active(&self, active: bool) {
+        self.set_property("active", active);
+    }
+}
+
+impl Default for Link {
+    fn default() -> Self {
+        Self::new()
+    }
+}

src/ui/graph/mod.rs

@@ -0,0 +1,26 @@
+// Copyright 2021 Tom A. Wagner <tom.a.wagner@protonmail.com>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 3 as published by
+// the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// SPDX-License-Identifier: GPL-3.0-only
+
+mod graph_view;
+pub use graph_view::*;
+mod node;
+pub use node::*;
+mod port;
+pub use port::*;
+mod link;
+pub use link::*;
+mod zoomentry;
+pub use zoomentry::*;

src/ui/graph/node.rs

@@ -0,0 +1,145 @@
+// Copyright 2021 Tom A. Wagner <tom.a.wagner@protonmail.com>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 3 as published by
+// the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// SPDX-License-Identifier: GPL-3.0-only
+
+use gtk::{glib, prelude::*, subclass::prelude::*};
+use pipewire::spa::Direction;
+
+use super::Port;
+
+mod imp {
+    use super::*;
+
+    use std::{
+        cell::{Cell, RefCell},
+        collections::HashSet,
+    };
+
+    #[derive(glib::Properties)]
+    #[properties(wrapper_type = super::Node)]
+    pub struct Node {
+        #[property(get, set, construct_only)]
+        pub(super) pipewire_id: Cell<u32>,
+        pub(super) grid: gtk::Grid,
+        #[property(
+            name = "name", type = String,
+            get = |this: &Self| this.label.text().to_string(),
+            set = |this: &Self, val| {
+                this.label.set_text(val);
+                this.label.set_tooltip_text(Some(val));
+            }
+        )]
+        pub(super) label: gtk::Label,
+        pub(super) ports: RefCell<HashSet<Port>>,
+        pub(super) num_ports_in: Cell<i32>,
+        pub(super) num_ports_out: Cell<i32>,
+    }
+
+    #[glib::object_subclass]
+    impl ObjectSubclass for Node {
+        const NAME: &'static str = "HelvumNode";
+        type Type = super::Node;
+        type ParentType = gtk::Widget;
+
+        fn class_init(klass: &mut Self::Class) {
+            klass.set_layout_manager_type::<gtk::BinLayout>();
+        }
+
+        fn new() -> Self {
+            let grid = gtk::Grid::new();
+
+            let label = gtk::Label::new(None);
+            label.set_wrap(true);
+            label.set_lines(2);
+            label.set_max_width_chars(20);
+            label.set_ellipsize(gtk::pango::EllipsizeMode::End);
+
+            grid.attach(&label, 0, 0, 2, 1);
+
+            // Display a grab cursor when the mouse is over the label so the user knows the node can be dragged.
+            label.set_cursor(gtk::gdk::Cursor::from_name("grab", None).as_ref());
+
+            Self {
+                pipewire_id: Cell::new(0),
+                grid,
+                label,
+                ports: RefCell::new(HashSet::new()),
+                num_ports_in: Cell::new(0),
+                num_ports_out: Cell::new(0),
+            }
+        }
+    }
+
+    #[glib::derived_properties]
+    impl ObjectImpl for Node {
+        fn constructed(&self) {
+            self.parent_constructed();
+            self.grid.set_parent(&*self.obj());
+        }
+
+        fn dispose(&self) {
+            self.grid.unparent();
+        }
+    }
+
+    impl WidgetImpl for Node {}
+}
+
+glib::wrapper! {
+    pub struct Node(ObjectSubclass<imp::Node>)
+        @extends gtk::Widget;
+}
+
+impl Node {
+    pub fn new(name: &str, pipewire_id: u32) -> Self {
+        glib::Object::builder()
+            .property("name", name)
+            .property("pipewire-id", pipewire_id)
+            .build()
+    }
+
+    pub fn add_port(&self, port: Port) {
+        let imp = self.imp();
+
+        match port.direction() {
+            Direction::Input => {
+                imp.grid.attach(&port, 0, imp.num_ports_in.get() + 1, 1, 1);
+                imp.num_ports_in.set(imp.num_ports_in.get() + 1);
+            }
+            Direction::Output => {
+                imp.grid.attach(&port, 1, imp.num_ports_out.get() + 1, 1, 1);
+                imp.num_ports_out.set(imp.num_ports_out.get() + 1);
+            }
+            _ => unreachable!(),
+        }
+
+        imp.ports.borrow_mut().insert(port);
+    }
+
+    pub fn remove_port(&self, port: &Port) {
+        let imp = self.imp();
+        if imp.ports.borrow_mut().remove(port) {
+            match port.direction() {
+                Direction::Input => imp.num_ports_in.set(imp.num_ports_in.get() - 1),
+                Direction::Output => imp.num_ports_in.set(imp.num_ports_out.get() - 1),
+                _ => unreachable!(),
+            }
+
+            port.unparent();
+        } else {
+            log::warn!("Tried to remove non-existant port widget from node");
+        }
+    }
+}

src/ui/graph/port.rs

@@ -0,0 +1,250 @@
+// Copyright 2021 Tom A. Wagner <tom.a.wagner@protonmail.com>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 3 as published by
+// the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// SPDX-License-Identifier: GPL-3.0-only
+
+use gtk::{
+    gdk,
+    glib::{self, subclass::Signal},
+    graphene,
+    prelude::*,
+    subclass::prelude::*,
+};
+use pipewire::spa::Direction;
+
+use crate::MediaType;
+
+mod imp {
+    use super::*;
+
+    use once_cell::{sync::Lazy, unsync::OnceCell};
+    use pipewire::spa::Direction;
+
+    /// Graphical representation of a pipewire port.
+    #[derive(Default, glib::Properties)]
+    #[properties(wrapper_type = super::Port)]
+    pub struct Port {
+        #[property(get, set, construct_only)]
+        pub(super) pipewire_id: OnceCell<u32>,
+        #[property(
+            name = "name", type = String,
+            get = |this: &Self| this.label.text().to_string(),
+            set = |this: &Self, val| {
+                this.label.set_text(val);
+                this.label.set_tooltip_text(Some(val));
+            }
+        )]
+        pub(super) label: gtk::Label,
+        pub(super) direction: OnceCell<Direction>,
+    }
+
+    #[glib::object_subclass]
+    impl ObjectSubclass for Port {
+        const NAME: &'static str = "HelvumPort";
+        type Type = super::Port;
+        type ParentType = gtk::Widget;
+
+        fn class_init(klass: &mut Self::Class) {
+            klass.set_layout_manager_type::<gtk::BinLayout>();
+
+            // Make it look like a GTK button.
+            klass.set_css_name("button");
+        }
+    }
+
+    #[glib::derived_properties]
+    impl ObjectImpl for Port {
+        fn constructed(&self) {
+            self.parent_constructed();
+
+            self.label.set_parent(&*self.obj());
+            self.label.set_wrap(true);
+            self.label.set_lines(2);
+            self.label.set_max_width_chars(20);
+            self.label.set_ellipsize(gtk::pango::EllipsizeMode::End);
+
+            self.setup_port_drag_and_drop();
+        }
+
+        fn dispose(&self) {
+            self.label.unparent()
+        }
+
+        fn signals() -> &'static [Signal] {
+            static SIGNALS: Lazy<Vec<Signal>> = Lazy::new(|| {
+                vec![Signal::builder("port-toggled")
+                    // Provide id of output port and input port to signal handler.
+                    .param_types([<u32>::static_type(), <u32>::static_type()])
+                    .build()]
+            });
+
+            SIGNALS.as_ref()
+        }
+    }
+    impl WidgetImpl for Port {}
+
+    impl Port {
+        fn setup_port_drag_and_drop(&self) {
+            let obj = &*self.obj();
+
+            // Add a drag source and drop target controller with the type depending on direction,
+            // they will be responsible for link creation by dragging an output port onto an input port or the other way around.
+            // The port will simply provide its pipewire id to the drag target.
+            // The drop target will accept the source port and use it to emit its `port-toggled` signal.
+
+            // FIXME: We should protect against different media types, e.g. it should not be possible to drop a video port on an audio port.
+
+            let drag_src = gtk::DragSource::builder()
+                .content(&gdk::ContentProvider::for_value(&obj.to_value()))
+                .build();
+            // Override the default drag icon with an empty one so that only a grab cursor is shown.
+            // The graph will render a link from the source port to the cursor to visualize the drag instead.
+            drag_src.set_icon(Some(&gdk::Paintable::new_empty(0, 0)), 0, 0);
+            drag_src.connect_drag_begin(|drag_source, _| {
+                let port = drag_source
+                    .widget()
+                    .dynamic_cast::<super::Port>()
+                    .expect("Widget should be a Port");
+
+                log::trace!("Drag started from port {}", port.pipewire_id());
+            });
+            drag_src.connect_drag_cancel(|drag_source, _, _| {
+                let port = drag_source
+                    .widget()
+                    .dynamic_cast::<super::Port>()
+                    .expect("Widget should be a Port");
+
+                log::trace!("Drag from port {} was cancelled", port.pipewire_id());
+
+                false
+            });
+            obj.add_controller(drag_src);
+
+            let drop_target =
+                gtk::DropTarget::new(super::Port::static_type(), gdk::DragAction::COPY);
+            drop_target.set_preload(true);
+            drop_target.connect_value_notify(|drop_target| {
+                let port = drop_target
+                    .widget()
+                    .dynamic_cast::<super::Port>()
+                    .expect("Widget should be a Port");
+
+                let Some(value) = drop_target.value() else {
+                    return;
+                };
+
+                let other_port: super::Port = value.get().expect("Drop value should be a port");
+
+                // Disallow drags between two ports that have the same direction
+                if !port.is_linkable_to(&other_port) {
+                    // FIXME: For some reason, this prints error:
+                    //        "gdk_drop_get_actions: assertion 'GDK_IS_DROP (self)' failed"
+                    drop_target.reject();
+                }
+            });
+            drop_target.connect_drop(|drop_target, val, _, _| {
+                let port = drop_target
+                    .widget()
+                    .dynamic_cast::<super::Port>()
+                    .expect("Widget should be a Port");
+                let other_port = val
+                    .get::<super::Port>()
+                    .expect("Dropped value should be a Port");
+
+                // Do not accept a drop between imcompatible ports
+                if !port.is_linkable_to(&other_port) {
+                    log::warn!("Tried to link incompatible ports");
+                    return false;
+                }
+
+                let (output_port, input_port) = match port.direction() {
+                    Direction::Output => (&port, &other_port),
+                    Direction::Input => (&other_port, &port),
+                    _ => unreachable!(),
+                };
+
+                port.emit_by_name::<()>(
+                    "port-toggled",
+                    &[&output_port.pipewire_id(), &input_port.pipewire_id()],
+                );
+
+                true
+            });
+            obj.add_controller(drop_target);
+        }
+    }
+}
+
+glib::wrapper! {
+    pub struct Port(ObjectSubclass<imp::Port>)
+        @extends gtk::Widget;
+}
+
+impl Port {
+    pub fn new(id: u32, name: &str, direction: Direction, media_type: Option<MediaType>) -> Self {
+        // Create the widget and initialize needed fields
+        let res: Self = glib::Object::builder()
+            .property("pipewire-id", id)
+            .property("name", name)
+            .build();
+
+        let imp = res.imp();
+
+        imp.direction
+            .set(direction)
+            .expect("Port direction already set");
+
+        // Display a grab cursor when the mouse is over the port so the user knows it can be dragged to another port.
+        res.set_cursor(gtk::gdk::Cursor::from_name("grab", None).as_ref());
+
+        // Color the port according to its media type.
+        match media_type {
+            Some(MediaType::Video) => res.add_css_class("video"),
+            Some(MediaType::Audio) => res.add_css_class("audio"),
+            Some(MediaType::Midi) => res.add_css_class("midi"),
+            None => {}
+        }
+
+        res
+    }
+
+    pub fn direction(&self) -> Direction {
+        *self
+            .imp()
+            .direction
+            .get()
+            .expect("Port direction is not set")
+    }
+
+    pub fn link_anchor(&self) -> graphene::Point {
+        let style_context = self.style_context();
+        let padding_right: f32 = style_context.padding().right().into();
+        let border_right: f32 = style_context.border().right().into();
+        let padding_left: f32 = style_context.padding().left().into();
+        let border_left: f32 = style_context.border().left().into();
+
+        graphene::Point::new(
+            match self.direction() {
+                Direction::Output => self.width() as f32 + padding_right + border_right,
+                Direction::Input => 0.0 - padding_left - border_left,
+                _ => unreachable!(),
+            },
+            self.height() as f32 / 2.0,
+        )
+    }
+
+    pub fn is_linkable_to(&self, other_port: &Self) -> bool {
+        self.direction() != other_port.direction()
+    }
+}

src/ui/graph/zoomentry.rs

@@ -0,0 +1,170 @@
+use gtk::{glib, prelude::*, subclass::prelude::*};
+
+use super::GraphView;
+
+mod imp {
+    use std::cell::RefCell;
+
+    use super::*;
+
+    use gtk::{gio, glib::clone};
+    use once_cell::sync::Lazy;
+
+    #[derive(gtk::CompositeTemplate)]
+    #[template(file = "zoomentry.ui")]
+    pub struct ZoomEntry {
+        pub graphview: RefCell<Option<GraphView>>,
+        #[template_child]
+        pub zoom_out_button: TemplateChild<gtk::Button>,
+        #[template_child]
+        pub zoom_in_button: TemplateChild<gtk::Button>,
+        #[template_child]
+        pub entry: TemplateChild<gtk::Entry>,
+        pub popover: gtk::PopoverMenu,
+    }
+
+    impl Default for ZoomEntry {
+        fn default() -> Self {
+            let menu = gio::Menu::new();
+            menu.append(Some("30%"), Some("win.set-zoom(0.30)"));
+            menu.append(Some("50%"), Some("win.set-zoom(0.50)"));
+            menu.append(Some("75%"), Some("win.set-zoom(0.75)"));
+            menu.append(Some("100%"), Some("win.set-zoom(1.0)"));
+            menu.append(Some("150%"), Some("win.set-zoom(1.5)"));
+            menu.append(Some("200%"), Some("win.set-zoom(2.0)"));
+            menu.append(Some("300%"), Some("win.set-zoom(3.0)"));
+            let popover = gtk::PopoverMenu::from_model(Some(&menu));
+
+            ZoomEntry {
+                graphview: Default::default(),
+                zoom_out_button: Default::default(),
+                zoom_in_button: Default::default(),
+                entry: Default::default(),
+                popover,
+            }
+        }
+    }
+
+    #[glib::object_subclass]
+    impl ObjectSubclass for ZoomEntry {
+        const NAME: &'static str = "HelvumZoomEntry";
+        type Type = super::ZoomEntry;
+        type ParentType = gtk::Box;
+
+        fn class_init(klass: &mut Self::Class) {
+            klass.bind_template();
+        }
+
+        fn instance_init(obj: &glib::subclass::InitializingObject<Self>) {
+            obj.init_template();
+        }
+    }
+
+    impl ObjectImpl for ZoomEntry {
+        fn constructed(&self) {
+            self.parent_constructed();
+
+            self.zoom_out_button
+                .connect_clicked(clone!(@weak self as imp => move |_| {
+                    let graphview = imp.graphview.borrow();
+                    if let Some(ref graphview) = *graphview {
+                        graphview.set_zoom_factor(graphview.zoom_factor() - 0.1, None);
+                    }
+                }));
+
+            self.zoom_in_button
+                .connect_clicked(clone!(@weak self as imp => move |_| {
+                    let graphview = imp.graphview.borrow();
+                    if let Some(ref graphview) = *graphview {
+                        graphview.set_zoom_factor(graphview.zoom_factor() + 0.1, None);
+                    }
+                }));
+
+            self.entry
+                .connect_activate(clone!(@weak self as imp => move |entry| {
+                    if let Ok(zoom_factor) = entry.text().trim_matches('%').parse::<f64>() {
+                        let graphview = imp.graphview.borrow();
+                        if let Some(ref graphview) = *graphview {
+                            graphview.set_zoom_factor(zoom_factor / 100.0, None);
+                        }
+                    }
+                }));
+            self.entry
+                .connect_icon_press(clone!(@weak self as imp => move |_, pos| {
+                    if pos == gtk::EntryIconPosition::Secondary {
+                        imp.popover.show();
+                    }
+                }));
+
+            self.popover.set_parent(&self.entry.get());
+        }
+
+        fn dispose(&self) {
+            self.popover.unparent();
+
+            while let Some(child) = self.obj().first_child() {
+                child.unparent();
+            }
+        }
+
+        fn properties() -> &'static [glib::ParamSpec] {
+            static PROPERTIES: Lazy<Vec<glib::ParamSpec>> = Lazy::new(|| {
+                vec![glib::ParamSpecObject::builder::<GraphView>("zoomed-widget")
+                    .flags(glib::ParamFlags::READWRITE | glib::ParamFlags::CONSTRUCT)
+                    .build()]
+            });
+
+            PROPERTIES.as_ref()
+        }
+
+        fn property(&self, _id: usize, pspec: &glib::ParamSpec) -> glib::Value {
+            match pspec.name() {
+                "zoomed-widget" => self.graphview.borrow().to_value(),
+                _ => unimplemented!(),
+            }
+        }
+
+        fn set_property(&self, _id: usize, value: &glib::Value, pspec: &glib::ParamSpec) {
+            match pspec.name() {
+                "zoomed-widget" => {
+                    let widget: GraphView = value.get().unwrap();
+                    widget.connect_notify_local(
+                        Some("zoom-factor"),
+                        clone!(@weak self as imp => move |graphview, _| {
+                            imp.update_zoom_factor_text(graphview.zoom_factor());
+                        }),
+                    );
+                    self.update_zoom_factor_text(widget.zoom_factor());
+                    *self.graphview.borrow_mut() = Some(widget);
+                }
+                _ => unimplemented!(),
+            }
+        }
+    }
+    impl WidgetImpl for ZoomEntry {}
+    impl BoxImpl for ZoomEntry {}
+
+    impl ZoomEntry {
+        /// Update the text contained in the combobox's entry to reflect the provided zoom factor.
+        ///
+        /// This does not update the associated [`GraphView`]s zoom level.
+        fn update_zoom_factor_text(&self, zoom_factor: f64) {
+            self.entry
+                .buffer()
+                .set_text(format!("{factor:.0}%", factor = zoom_factor * 100.));
+        }
+    }
+}
+
+glib::wrapper! {
+    pub struct ZoomEntry(ObjectSubclass<imp::ZoomEntry>)
+        @extends gtk::Box, gtk::Widget;
+}
+
+impl ZoomEntry {
+    pub fn new(zoomed_widget: &GraphView) -> Self {
+        glib::Object::builder()
+            .property("zoomed-widget", zoomed_widget)
+            .build()
+    }
+}

src/ui/graph/zoomentry.ui

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<interface>
+  <template class="HelvumZoomEntry" parent="GtkBox">
+    <child>
+      <object class="GtkButton" id="zoom_out_button">
+        <property name="icon-name">zoom-out-symbolic</property>
+        <property name="tooltip-text">Zoom out</property>
+      </object>
+    </child>
+    <child>
+      <object class="GtkEntry" id="entry">
+        <property name="secondary-icon-name">go-down-symbolic</property>
+        <property name="input-purpose">digits</property>
+      </object>
+    </child>
+    <child>
+      <object class="GtkButton" id="zoom_in_button">
+        <property name="icon-name">zoom-in-symbolic</property>
+        <property name="tooltip-text">Zoom in</property>
+      </object>
+    </child>
+    <style>
+      <class name="linked"/>
+    </style>
+  </template>
+</interface>

src/ui/mod.rs

@@ -0,0 +1,21 @@
+// Copyright 2021 Tom A. Wagner <tom.a.wagner@protonmail.com>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 3 as published by
+// the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// SPDX-License-Identifier: GPL-3.0-only
+
+//! The view presented to the user.
+//!
+//! This module contains gtk widgets needed to present the graphical user interface.
+
+pub mod graph;

src/view/graph_view.rs

@@ -1,320 +0,0 @@
-use super::{Node, Port};
-
-use gtk::{
-    glib::{self, clone},
-    graphene, gsk,
-    prelude::*,
-    subclass::prelude::*,
-};
-
-use std::collections::HashMap;
-
-mod imp {
-    use super::*;
-
-    use std::{cell::RefCell, rc::Rc};
-
-    use log::warn;
-
-    #[derive(Default)]
-    pub struct GraphView {
-        pub(super) nodes: RefCell<HashMap<u32, Node>>,
-        pub(super) links: RefCell<HashMap<u32, crate::PipewireLink>>,
-    }
-
-    #[glib::object_subclass]
-    impl ObjectSubclass for GraphView {
-        const NAME: &'static str = "GraphView";
-        type Type = super::GraphView;
-        type ParentType = gtk::Widget;
-
-        fn class_init(klass: &mut Self::Class) {
-            // The layout manager determines how child widgets are laid out.
-            klass.set_layout_manager_type::<gtk::FixedLayout>();
-        }
-    }
-
-    impl ObjectImpl for GraphView {
-        fn constructed(&self, obj: &Self::Type) {
-            self.parent_constructed(obj);
-
-            let drag_state = Rc::new(RefCell::new(None));
-            let drag_controller = gtk::GestureDrag::new();
-
-            drag_controller.connect_drag_begin(
-                clone!(@strong drag_state => move |drag_controller, x, y| {
-                let mut drag_state = drag_state.borrow_mut();
-                let widget = drag_controller
-                    .widget()
-                    .expect("drag-begin event has no widget")
-                    .dynamic_cast::<Self::Type>()
-                    .expect("drag-begin event is not on the GraphView");
-                // pick() should at least return the widget itself.
-                let target = widget.pick(x, y, gtk::PickFlags::DEFAULT).expect("drag-begin pick() did not return a widget");
-                *drag_state = if target.ancestor(Port::static_type()).is_some() {
-                    // The user targeted a port, so the dragging should be handled by the Port
-                    // component instead of here.
-                    None
-                } else if let Some(target) = target.ancestor(Node::static_type()) {
-                    // The user targeted a Node without targeting a specific Port.
-                    // Drag the Node around the screen.
-                    let (x, y) = widget.get_node_position(&target);
-                    Some((target, x, y))
-                } else {
-                    None
-                }
-            }));
-            drag_controller.connect_drag_update(
-                clone!(@strong drag_state => move |drag_controller, x, y| {
-                    let widget = drag_controller
-                        .widget()
-                        .expect("drag-update event has no widget")
-                        .dynamic_cast::<Self::Type>()
-                        .expect("drag-update event is not on the GraphView");
-                    let drag_state = drag_state.borrow();
-                    if let Some((ref node, x1, y1)) = *drag_state {
-                        widget.move_node(node, x1 + x as f32, y1 + y as f32);
-                    }
-                }
-                ),
-            );
-            obj.add_controller(&drag_controller);
-        }
-
-        fn dispose(&self, _obj: &Self::Type) {
-            self.nodes
-                .borrow()
-                .values()
-                .for_each(|node| node.unparent())
-        }
-    }
-
-    impl WidgetImpl for GraphView {
-        fn snapshot(&self, widget: &Self::Type, snapshot: &gtk::Snapshot) {
-            /* FIXME: A lot of hardcoded values in here.
-            Try to use relative units (em) and colours from the theme as much as possible. */
-
-            let alloc = widget.allocation();
-
-            let cr = snapshot
-                .append_cairo(&graphene::Rect::new(
-                    0.0,
-                    0.0,
-                    alloc.width as f32,
-                    alloc.height as f32,
-                ))
-                .expect("Failed to get cairo context");
-
-            // Try to replace the background color with a darker one from the theme.
-            if let Some(rgba) = widget.style_context().lookup_color("text_view_bg") {
-                cr.set_source_rgb(rgba.red.into(), rgba.green.into(), rgba.blue.into());
-                if let Err(e) = cr.paint() {
-                    warn!("Failed to paint graphview background: {}", e);
-                };
-            } // TODO: else log colour not found
-
-            // Draw a nice grid on the background.
-            cr.set_source_rgb(0.18, 0.18, 0.18);
-            cr.set_line_width(0.2); // TODO: Set to 1px
-            let mut y = 0.0;
-            while y < alloc.height.into() {
-                cr.move_to(0.0, y);
-                cr.line_to(alloc.width as f64, y);
-                y += 20.0; // TODO: Change to em;
-            }
-            let mut x = 0.0;
-            while x < alloc.width as f64 {
-                cr.move_to(x, 0.0);
-                cr.line_to(x, alloc.height as f64);
-                x += 20.0; // TODO: Change to em;
-            }
-            if let Err(e) = cr.stroke() {
-                warn!("Failed to draw graphview grid: {}", e);
-            };
-
-            // Draw all links
-            cr.set_line_width(2.0);
-            cr.set_source_rgb(0.0, 0.0, 0.0);
-            for link in self.links.borrow().values() {
-                if let Some((from_x, from_y, to_x, to_y)) = self.get_link_coordinates(link) {
-                    cr.move_to(from_x, from_y);
-                    cr.curve_to(from_x + 75.0, from_y, to_x - 75.0, to_y, to_x, to_y);
-                    if let Err(e) = cr.stroke() {
-                        warn!("Failed to draw graphview links: {}", e);
-                    };
-                } else {
-                    log::warn!("Could not get allocation of ports of link: {:?}", link);
-                }
-            }
-
-            // Draw all children
-            self.nodes
-                .borrow()
-                .values()
-                .for_each(|node| self.instance().snapshot_child(node, snapshot));
-        }
-    }
-
-    impl GraphView {
-        /// Get coordinates for the drawn link to start at and to end at.
-        ///
-        /// # Returns
-        /// Some((from_x, from_y, to_x, to_y)) if all objects the links refers to exist as widgets.
-        fn get_link_coordinates(&self, link: &crate::PipewireLink) -> Option<(f64, f64, f64, f64)> {
-            let nodes = self.nodes.borrow();
-
-            // For some reason, gtk4::WidgetExt::translate_coordinates gives me incorrect values,
-            // so we manually calculate the needed offsets here.
-
-            let from_port = &nodes.get(&link.node_from)?.get_port(link.port_from)?;
-            let gtk::Allocation {
-                x: mut fx,
-                y: mut fy,
-                width: fw,
-                height: fh,
-            } = from_port.allocation();
-            let from_node = from_port
-                .ancestor(Node::static_type())
-                .expect("Port is not a child of a node");
-            let gtk::Allocation { x: fnx, y: fny, .. } = from_node.allocation();
-            fx += fnx + fw;
-            fy += fny + (fh / 2);
-
-            let to_port = &nodes.get(&link.node_to)?.get_port(link.port_to)?;
-            let gtk::Allocation {
-                x: mut tx,
-                y: mut ty,
-                height: th,
-                ..
-            } = to_port.allocation();
-            let to_node = to_port
-                .ancestor(Node::static_type())
-                .expect("Port is not a child of a node");
-            let gtk::Allocation { x: tnx, y: tny, .. } = to_node.allocation();
-            tx += tnx;
-            ty += tny + (th / 2);
-
-            Some((fx as f64, fy as f64, tx as f64, ty as f64))
-        }
-    }
-}
-
-glib::wrapper! {
-    pub struct GraphView(ObjectSubclass<imp::GraphView>)
-        @extends gtk::Widget;
-}
-
-impl GraphView {
-    pub fn new() -> Self {
-        glib::Object::new(&[]).expect("Failed to create GraphView")
-    }
-
-    pub fn add_node(&self, id: u32, node: Node) {
-        let private = imp::GraphView::from_instance(self);
-        node.set_parent(self);
-
-        // Place widgets in colums of 4, growing down, then right.
-        // TODO: Make a better positioning algorithm.
-        let x = (private.nodes.borrow().len() / 4) as f32 * 400.0; // This relies on integer division rounding down.
-        let y = private.nodes.borrow().len() as f32 % 4.0 * 100.0;
-
-        self.move_node(&node.clone().upcast(), x, y);
-
-        private.nodes.borrow_mut().insert(id, node);
-    }
-
-    pub fn remove_node(&self, id: u32) {
-        let private = imp::GraphView::from_instance(self);
-        let mut nodes = private.nodes.borrow_mut();
-        if let Some(node) = nodes.remove(&id) {
-            node.unparent();
-        }
-    }
-
-    pub fn add_port(&self, node_id: u32, port_id: u32, port: crate::view::port::Port) {
-        let private = imp::GraphView::from_instance(self);
-
-        if let Some(node) = private.nodes.borrow_mut().get_mut(&node_id) {
-            node.add_port(port_id, port);
-        } else {
-            // FIXME: Log this instead
-            log::error!(
-                "Node with id {} not found when trying to add port with id {} to graph",
-                node_id,
-                port_id
-            );
-        }
-    }
-
-    pub fn remove_port(&self, id: u32, node_id: u32) {
-        let private = imp::GraphView::from_instance(self);
-        let nodes = private.nodes.borrow();
-        if let Some(node) = nodes.get(&node_id) {
-            node.remove_port(id);
-        }
-    }
-
-    /// Add a link to the graph.
-    ///
-    /// `add_link` takes three arguments: `link_id` is the id of the link as assigned by the pipewire server,
-    /// `from` and `to` are the id's of the ingoing and outgoing port, respectively.
-    pub fn add_link(&self, link_id: u32, link: crate::PipewireLink) {
-        let private = imp::GraphView::from_instance(self);
-        private.links.borrow_mut().insert(link_id, link);
-        self.queue_draw();
-    }
-
-    pub fn remove_link(&self, id: u32) {
-        let private = imp::GraphView::from_instance(self);
-        let mut links = private.links.borrow_mut();
-        links.remove(&id);
-
-        self.queue_draw();
-    }
-
-    pub(super) fn get_node_position(&self, node: &gtk::Widget) -> (f32, f32) {
-        let layout_manager = self
-            .layout_manager()
-            .expect("Failed to get layout manager")
-            .dynamic_cast::<gtk::FixedLayout>()
-            .expect("Failed to cast to FixedLayout");
-
-        let node = layout_manager
-            .layout_child(node)
-            .expect("Could not get layout child")
-            .dynamic_cast::<gtk::FixedLayoutChild>()
-            .expect("Could not cast to FixedLayoutChild");
-        let transform = node.transform().unwrap_or_default();
-        transform.to_translate()
-    }
-
-    pub(super) fn move_node(&self, node: &gtk::Widget, x: f32, y: f32) {
-        let layout_manager = self
-            .layout_manager()
-            .expect("Failed to get layout manager")
-            .dynamic_cast::<gtk::FixedLayout>()
-            .expect("Failed to cast to FixedLayout");
-
-        let transform = gsk::Transform::new()
-            // Nodes should not be able to be dragged out of the view, so we use `max(coordinate, 0.0)` to prevent that.
-            .translate(&graphene::Point::new(f32::max(x, 0.0), f32::max(y, 0.0)))
-            .unwrap();
-
-        layout_manager
-            .layout_child(node)
-            .expect("Could not get layout child")
-            .dynamic_cast::<gtk::FixedLayoutChild>()
-            .expect("Could not cast to FixedLayoutChild")
-            .set_transform(&transform);
-
-        // FIXME: If links become proper widgets,
-        // we don't need to redraw the full graph everytime.
-        self.queue_draw();
-    }
-}
-
-impl Default for GraphView {
-    fn default() -> Self {
-        Self::new()
-    }
-}

src/view/mod.rs

@@ -1,11 +0,0 @@
-//! The view presented to the user.
-//!
-//! This module contains gtk widgets needed to present the graphical user interface.
-
-mod graph_view;
-mod node;
-mod port;
-
-pub use graph_view::GraphView;
-pub use node::Node;
-pub use port::Port;

src/view/node.rs

@@ -1,114 +0,0 @@
-use gtk::{glib, prelude::*, subclass::prelude::*};
-use pipewire::spa::Direction;
-
-use std::{collections::HashMap, rc::Rc};
-
-mod imp {
-    use super::*;
-
-    use std::cell::{Cell, RefCell};
-
-    pub struct Node {
-        pub(super) grid: gtk::Grid,
-        pub(super) label: gtk::Label,
-        pub(super) ports: RefCell<HashMap<u32, Rc<crate::view::port::Port>>>,
-        pub(super) num_ports_in: Cell<u32>,
-        pub(super) num_ports_out: Cell<u32>,
-    }
-
-    #[glib::object_subclass]
-    impl ObjectSubclass for Node {
-        const NAME: &'static str = "Node";
-        type Type = super::Node;
-        type ParentType = gtk::Widget;
-
-        fn class_init(klass: &mut Self::Class) {
-            klass.set_layout_manager_type::<gtk::BinLayout>();
-        }
-
-        fn new() -> Self {
-            let grid = gtk::Grid::new();
-            let label = gtk::Label::new(None);
-
-            grid.attach(&label, 0, 0, 2, 1);
-
-            // Display a grab cursor when the mouse is over the label so the user knows the node can be dragged.
-            label.set_cursor(gtk::gdk::Cursor::from_name("grab", None).as_ref());
-
-            Self {
-                grid,
-                label,
-                ports: RefCell::new(HashMap::new()),
-                num_ports_in: Cell::new(0),
-                num_ports_out: Cell::new(0),
-            }
-        }
-    }
-
-    impl ObjectImpl for Node {
-        fn constructed(&self, obj: &Self::Type) {
-            self.parent_constructed(obj);
-            self.grid.set_parent(obj);
-        }
-
-        fn dispose(&self, _obj: &Self::Type) {
-            self.grid.unparent();
-        }
-    }
-
-    impl WidgetImpl for Node {}
-}
-
-glib::wrapper! {
-    pub struct Node(ObjectSubclass<imp::Node>)
-        @extends gtk::Widget;
-}
-
-impl Node {
-    pub fn new(name: &str) -> Self {
-        let res: Self = glib::Object::new(&[]).expect("Failed to create Node");
-        let private = imp::Node::from_instance(&res);
-
-        private.label.set_text(name);
-
-        res
-    }
-
-    pub fn add_port(&mut self, id: u32, port: super::port::Port) {
-        let private = imp::Node::from_instance(self);
-
-        match port.direction() {
-            Direction::Input => {
-                private
-                    .grid
-                    .attach(&port, 0, private.num_ports_in.get() as i32 + 1, 1, 1);
-                private.num_ports_in.set(private.num_ports_in.get() + 1);
-            }
-            Direction::Output => {
-                private
-                    .grid
-                    .attach(&port, 1, private.num_ports_out.get() as i32 + 1, 1, 1);
-                private.num_ports_out.set(private.num_ports_out.get() + 1);
-            }
-        }
-
-        private.ports.borrow_mut().insert(id, Rc::new(port));
-    }
-
-    pub fn get_port(&self, id: u32) -> Option<Rc<super::port::Port>> {
-        let private = imp::Node::from_instance(self);
-        private.ports.borrow_mut().get(&id).cloned()
-    }
-
-    pub fn remove_port(&self, id: u32) {
-        let private = imp::Node::from_instance(self);
-        if let Some(port) = private.ports.borrow_mut().remove(&id) {
-            match port.direction() {
-                Direction::Input => private.num_ports_in.set(private.num_ports_in.get() - 1),
-                Direction::Output => private.num_ports_in.set(private.num_ports_out.get() - 1),
-            }
-
-            port.unparent();
-        }
-    }
-}

src/view/port.rs

@@ -1,130 +0,0 @@
-use gtk::{
-    gdk,
-    glib::{self, subclass::Signal},
-    prelude::*,
-    subclass::prelude::*,
-};
-use log::warn;
-use pipewire::spa::Direction;
-
-use crate::MediaType;
-
-mod imp {
-    use once_cell::{sync::Lazy, unsync::OnceCell};
-    use pipewire::spa::Direction;
-
-    use super::*;
-
-    /// Graphical representation of a pipewire port.
-    #[derive(Default)]
-    pub struct Port {
-        pub(super) id: OnceCell<u32>,
-        pub(super) direction: OnceCell<Direction>,
-    }
-
-    #[glib::object_subclass]
-    impl ObjectSubclass for Port {
-        const NAME: &'static str = "Port";
-        type Type = super::Port;
-        type ParentType = gtk::Button;
-    }
-
-    impl ObjectImpl for Port {
-        fn signals() -> &'static [Signal] {
-            static SIGNALS: Lazy<Vec<Signal>> = Lazy::new(|| {
-                vec![Signal::builder(
-                    "port-toggled",
-                    // Provide id of output port and input port to signal handler.
-                    &[<u32>::static_type().into(), <u32>::static_type().into()],
-                    // signal handler sends back nothing.
-                    <()>::static_type().into(),
-                )
-                .build()]
-            });
-
-            SIGNALS.as_ref()
-        }
-    }
-    impl WidgetImpl for Port {}
-    impl ButtonImpl for Port {}
-}
-
-glib::wrapper! {
-    pub struct Port(ObjectSubclass<imp::Port>)
-        @extends gtk::Button, gtk::Widget;
-}
-
-impl Port {
-    pub fn new(id: u32, name: &str, direction: Direction, media_type: Option<MediaType>) -> Self {
-        // Create the widget and initialize needed fields
-        let res: Self = glib::Object::new(&[]).expect("Failed to create Port");
-        let private = imp::Port::from_instance(&res);
-        private.id.set(id).expect("Port id already set");
-        private
-            .direction
-            .set(direction)
-            .expect("Port direction already set");
-
-        res.set_child(Some(&gtk::Label::new(Some(name))));
-
-        // Add either a drag source or drop target controller depending on direction,
-        // they will be responsible for link creation by dragging an output port onto an input port.
-        //
-        // FIXME: The type used for dragging is simply a u32.
-        //   This means that anything that provides a u32 could be dragged onto a input port,
-        //   leading to that port trying to create a link to an invalid output port.
-        //   We should use a newtype instead of a plain u32.
-        //   Additionally, this does not protect against e.g. dropping an outgoing audio port on an ingoing video port.
-        match direction {
-            Direction::Input => {
-                let drop_target = gtk::DropTarget::new(u32::static_type(), gdk::DragAction::COPY);
-                let this = res.clone();
-                drop_target.connect_drop(move |drop_target, val, _, _| {
-                    if let Ok(source_id) = val.get::<u32>() {
-                        // Get the callback registered in the widget and call it
-                        drop_target
-                            .widget()
-                            .expect("Drop target has no widget")
-                            .emit_by_name("port-toggled", &[&source_id, &this.id()])
-                            .expect("Failed to send signal");
-                    } else {
-                        warn!("Invalid type dropped on ingoing port");
-                    }
-
-                    true
-                });
-                res.add_controller(&drop_target);
-            }
-            Direction::Output => {
-                // The port will simply provide its pipewire id to the drag target.
-                let drag_src = gtk::DragSourceBuilder::new()
-                    .content(&gdk::ContentProvider::for_value(&(id.to_value())))
-                    .build();
-                res.add_controller(&drag_src);
-
-                // Display a grab cursor when the mouse is over the port so the user knows it can be dragged to another port.
-                res.set_cursor(gtk::gdk::Cursor::from_name("grab", None).as_ref());
-            }
-        }
-
-        // Color the port according to its media type.
-        match media_type {
-            Some(MediaType::Video) => res.add_css_class("video"),
-            Some(MediaType::Audio) => res.add_css_class("audio"),
-            Some(MediaType::Midi) => res.add_css_class("midi"),
-            None => {}
-        }
-
-        res
-    }
-
-    pub fn id(&self) -> u32 {
-        let private = imp::Port::from_instance(self);
-        private.id.get().copied().expect("Port id is not set")
-    }
-
-    pub fn direction(&self) -> &Direction {
-        let private = imp::Port::from_instance(self);
-        private.direction.get().expect("Port direction is not set")
-    }
-}