Color links and ports according to their formats

Format params for links and ports are now being watched for in the pipewire connection code.

The parsed media type is then set on the port widget / link object
and they are colored accordingly.

For ports, which were already colored before, this new method of determining the media type
should be more reliable and accurate as this uses the real Format/EnumFormat
params instead of parsing optional properties.

src/ui/graph/graph_view.rs

@@ -43,8 +43,27 @@ mod imp {
     };
     use log::warn;
     use once_cell::sync::Lazy;
+    use pipewire::spa::format::MediaType;
     use pipewire::spa::Direction;
 
+    pub struct Colors {
+        audio: gdk::RGBA,
+        video: gdk::RGBA,
+        midi: gdk::RGBA,
+        unknown: gdk::RGBA,
+    }
+
+    impl Colors {
+        pub fn color_for_media_type(&self, media_type: MediaType) -> &gdk::RGBA {
+            match media_type {
+                MediaType::Audio => &self.audio,
+                MediaType::Video => &self.video,
+                MediaType::Stream | MediaType::Application => &self.midi,
+                _ => &self.unknown,
+            }
+        }
+    }
+
     pub struct DragState {
         node: glib::WeakRef<Node>,
         /// This stores the offset of the pointer to the origin of the node,
@@ -510,6 +529,7 @@ mod imp {
             output_anchor: &Point,
             input_anchor: &Point,
             active: bool,
+            color: &gdk::RGBA,
         ) {
             let output_x: f64 = output_anchor.x().into();
             let output_y: f64 = output_anchor.y().into();
@@ -523,6 +543,13 @@ mod imp {
                 link_cr.set_dash(&[10.0, 5.0], 0.0);
             }
 
+            link_cr.set_source_rgba(
+                color.red().into(),
+                color.green().into(),
+                color.blue().into(),
+                color.alpha().into(),
+            );
+
             // 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.
@@ -551,7 +578,7 @@ mod imp {
             };
         }
 
-        fn draw_dragged_link(&self, port: &Port, link_cr: &cairo::Context) {
+        fn draw_dragged_link(&self, port: &Port, link_cr: &cairo::Context, colors: &Colors) {
             let Some(port_anchor) = port.compute_point(&*self.obj(), &port.link_anchor()) else {
                 return;
             };
@@ -579,7 +606,9 @@ mod imp {
                 _ => unreachable!(),
             };
 
-            self.draw_link(link_cr, output_anchor, input_anchor, false);
+            let color = &colors.color_for_media_type(MediaType::from_raw(port.media_type()));
+
+            self.draw_link(link_cr, output_anchor, input_anchor, false, color);
         }
 
         fn snapshot_links(&self, widget: &super::GraphView, snapshot: &gtk::Snapshot) {
@@ -594,30 +623,45 @@ mod imp {
 
             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(),
-            );
+            let colors = Colors {
+                audio: widget
+                    .style_context()
+                    .lookup_color("media-type-audio")
+                    .expect("color not found"),
+                video: widget
+                    .style_context()
+                    .lookup_color("media-type-video")
+                    .expect("color not found"),
+                midi: widget
+                    .style_context()
+                    .lookup_color("media-type-midi")
+                    .expect("color not found"),
+                unknown: widget
+                    .style_context()
+                    .lookup_color("media-type-unknown")
+                    .expect("color not found"),
+            };
 
             for link in self.links.borrow().iter() {
+                let color = &colors.color_for_media_type(link.media_type());
+
                 // 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());
+                self.draw_link(
+                    &link_cr,
+                    &output_anchor,
+                    &input_anchor,
+                    link.active(),
+                    color,
+                );
             }
 
             if let Some(port) = self.dragged_port.upgrade() {
-                self.draw_dragged_link(&port, &link_cr);
+                self.draw_dragged_link(&port, &link_cr, &colors);
             }
         }
 
@@ -793,6 +837,12 @@ impl GraphView {
                 graph.queue_draw();
             }),
         );
+        link.connect_notify_local(
+            Some("media-type"),
+            glib::clone!(@weak self as graph => move |_, _| {
+                graph.queue_draw();
+            }),
+        );
         self.imp().links.borrow_mut().insert(link);
         self.queue_draw();
     }