Restructure view module into ui folder, graph specific widgets into graph subfolder

src/ui/graph/port.rs

@@ -0,0 +1,251 @@
+// 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, clone, subclass::Signal},
+    prelude::*,
+    subclass::prelude::*,
+};
+use log::{trace, warn};
+use pipewire::spa::Direction;
+
+use crate::MediaType;
+
+/// A helper struct for linking a output port to an input port.
+/// It carries the output ports id.
+#[derive(Clone, Debug, glib::Boxed)]
+#[boxed_type(name = "HelvumForwardLink")]
+struct ForwardLink(u32);
+
+/// A helper struct for linking an input to an output port.
+/// It carries the input ports id.
+#[derive(Clone, Debug, glib::Boxed)]
+#[boxed_type(name = "HelvumReversedLink")]
+struct ReversedLink(u32);
+
+mod imp {
+    use glib::ParamFlags;
+    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) pipewire_id: OnceCell<u32>,
+        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");
+        }
+    }
+
+    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);
+        }
+
+        fn dispose(&self) {
+            self.label.unparent()
+        }
+
+        fn properties() -> &'static [glib::ParamSpec] {
+            static PROPERTIES: Lazy<Vec<glib::ParamSpec>> = Lazy::new(|| {
+                vec![
+                    glib::ParamSpecUInt::builder("pipewire-id")
+                        .flags(ParamFlags::READWRITE | ParamFlags::CONSTRUCT_ONLY)
+                        .build(),
+                    glib::ParamSpecString::builder("name").build(),
+                ]
+            });
+
+            PROPERTIES.as_ref()
+        }
+
+        fn property(&self, _id: usize, pspec: &glib::ParamSpec) -> glib::Value {
+            match pspec.name() {
+                "pipewire-id" => self.pipewire_id.get().unwrap().to_value(),
+                "name" => self.label.text().to_value(),
+                _ => unimplemented!(),
+            }
+        }
+
+        fn set_property(&self, _id: usize, value: &glib::Value, pspec: &glib::ParamSpec) {
+            match pspec.name() {
+                "name" => {
+                    self.label.set_text(value.get().unwrap());
+                    self.label.set_tooltip_text(value.get().ok());
+                }
+                "pipewire-id" => self.pipewire_id.set(value.get().unwrap()).unwrap(),
+                _ => unimplemented!(),
+            }
+        }
+
+        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 {}
+}
+
+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");
+
+        // 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.
+
+        // FIXME: We should protect against different media types, e.g. it should not be possible to drop a video port on an audio port.
+
+        // The port will simply provide its pipewire id to the drag target.
+        let drag_src = gtk::DragSource::builder()
+            .content(&gdk::ContentProvider::for_value(&match direction {
+                Direction::Input => ReversedLink(id).to_value(),
+                Direction::Output => ForwardLink(id).to_value(),
+            }))
+            .build();
+        drag_src.connect_drag_begin(clone!(@weak res as obj => move |source, _| {
+            trace!("Drag started from port {}", id);
+            let paintable = gtk::WidgetPaintable::new(Some(&obj));
+            source.set_icon(Some(&paintable), 0, 0);
+        }));
+        drag_src.connect_drag_cancel(move |_, _, _| {
+            trace!("Drag from port {} was cancelled", id);
+            false
+        });
+        res.add_controller(drag_src);
+
+        // The drop target will accept either a `ForwardLink` or `ReversedLink` depending in its own direction,
+        // and use it to emit its `port-toggled` signal.
+        let drop_target = gtk::DropTarget::new(
+            match direction {
+                Direction::Input => ForwardLink::static_type(),
+                Direction::Output => ReversedLink::static_type(),
+            },
+            gdk::DragAction::COPY,
+        );
+        match direction {
+            Direction::Input => {
+                drop_target.connect_drop(
+                    clone!(@weak res as this => @default-panic, move |drop_target, val, _, _| {
+                        if let Ok(ForwardLink(source_id)) = val.get::<ForwardLink>() {
+                            // Get the callback registered in the widget and call it
+                            drop_target
+                                .widget()
+                                .emit_by_name::<()>("port-toggled", &[&source_id, &this.pipewire_id()]);
+                        } else {
+                            warn!("Invalid type dropped on ingoing port");
+                        }
+
+                        true
+                    }),
+                );
+            }
+            Direction::Output => {
+                drop_target.connect_drop(
+                    clone!(@weak res as this => @default-panic, move |drop_target, val, _, _| {
+                        if let Ok(ReversedLink(target_id)) = val.get::<ReversedLink>() {
+                            // Get the callback registered in the widget and call it
+                            drop_target
+                                .widget()
+                                .emit_by_name::<()>("port-toggled", &[&this.pipewire_id(), &target_id]);
+                        } else {
+                            warn!("Invalid type dropped on outgoing port");
+                        }
+
+                        true
+                    }),
+                );
+            }
+        }
+        res.add_controller(drop_target);
+
+        // 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 pipewire_id(&self) -> u32 {
+        self.property("pipewire-id")
+    }
+
+    /// Get the nodes `name` property, which represents the displayed name.
+    pub fn name(&self) -> String {
+        self.property("name")
+    }
+
+    /// Set the nodes `name` property, which represents the displayed name.
+    pub fn set_name(&self, name: &str) {
+        self.set_property("name", name);
+    }
+
+    pub fn direction(&self) -> &Direction {
+        self.imp()
+            .direction
+            .get()
+            .expect("Port direction is not set")
+    }
+}