Use explicit sort order instead of comparison impls for gpui prims

Found this while looking into adding support for the Surface primitive
on Linux, for rendering video shares. In that case it would be
expensive to compare images for equality. `Eq` and `PartialEq` were
being required but not used here due to use of `Ord` and `PartialOrd`.

crates/gpui/src/scene.rs

@@ -128,13 +128,15 @@ impl Scene {
     }
 
     pub fn finish(&mut self) {
-        self.shadows.sort();
-        self.quads.sort();
-        self.paths.sort();
-        self.underlines.sort();
-        self.monochrome_sprites.sort();
-        self.polychrome_sprites.sort();
-        self.surfaces.sort();
+        self.shadows.sort_by_key(|shadow| shadow.order);
+        self.quads.sort_by_key(|quad| quad.order);
+        self.paths.sort_by_key(|path| path.order);
+        self.underlines.sort_by_key(|underline| underline.order);
+        self.monochrome_sprites
+            .sort_by_key(|sprite| (sprite.order, sprite.tile.tile_id));
+        self.polychrome_sprites
+            .sort_by_key(|sprite| (sprite.order, sprite.tile.tile_id));
+        self.surfaces.sort_by_key(|surface| surface.order);
     }
 
     #[cfg_attr(
@@ -196,7 +198,7 @@ pub(crate) enum PaintOperation {
     EndLayer,
 }
 
-#[derive(Clone, Ord, PartialOrd, Eq, PartialEq)]
+#[derive(Clone)]
 pub(crate) enum Primitive {
     Shadow(Shadow),
     Quad(Quad),
@@ -449,7 +451,7 @@ pub(crate) enum PrimitiveBatch<'a> {
     Surfaces(&'a [PaintSurface]),
 }
 
-#[derive(Default, Debug, Clone, Eq, PartialEq)]
+#[derive(Default, Debug, Clone)]
 #[repr(C)]
 pub(crate) struct Quad {
     pub order: DrawOrder,
@@ -462,25 +464,13 @@ pub(crate) struct Quad {
     pub border_widths: Edges<ScaledPixels>,
 }
 
-impl Ord for Quad {
-    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        self.order.cmp(&other.order)
-    }
-}
-
-impl PartialOrd for Quad {
-    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-        Some(self.cmp(other))
-    }
-}
-
 impl From<Quad> for Primitive {
     fn from(quad: Quad) -> Self {
         Primitive::Quad(quad)
     }
 }
 
-#[derive(Debug, Clone, Eq, PartialEq)]
+#[derive(Debug, Clone)]
 #[repr(C)]
 pub(crate) struct Underline {
     pub order: DrawOrder,
@@ -492,25 +482,13 @@ pub(crate) struct Underline {
     pub wavy: bool,
 }
 
-impl Ord for Underline {
-    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        self.order.cmp(&other.order)
-    }
-}
-
-impl PartialOrd for Underline {
-    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-        Some(self.cmp(other))
-    }
-}
-
 impl From<Underline> for Primitive {
     fn from(underline: Underline) -> Self {
         Primitive::Underline(underline)
     }
 }
 
-#[derive(Debug, Clone, Eq, PartialEq)]
+#[derive(Debug, Clone)]
 #[repr(C)]
 pub(crate) struct Shadow {
     pub order: DrawOrder,
@@ -521,18 +499,6 @@ pub(crate) struct Shadow {
     pub color: Hsla,
 }
 
-impl Ord for Shadow {
-    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        self.order.cmp(&other.order)
-    }
-}
-
-impl PartialOrd for Shadow {
-    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-        Some(self.cmp(other))
-    }
-}
-
 impl From<Shadow> for Primitive {
     fn from(shadow: Shadow) -> Self {
         Primitive::Shadow(shadow)
@@ -642,7 +608,7 @@ impl Default for TransformationMatrix {
     }
 }
 
-#[derive(Clone, Debug, Eq, PartialEq)]
+#[derive(Clone, Debug)]
 #[repr(C)]
 pub(crate) struct MonochromeSprite {
     pub order: DrawOrder,
@@ -654,28 +620,13 @@ pub(crate) struct MonochromeSprite {
     pub transformation: TransformationMatrix,
 }
 
-impl Ord for MonochromeSprite {
-    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        match self.order.cmp(&other.order) {
-            std::cmp::Ordering::Equal => self.tile.tile_id.cmp(&other.tile.tile_id),
-            order => order,
-        }
-    }
-}
-
-impl PartialOrd for MonochromeSprite {
-    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-        Some(self.cmp(other))
-    }
-}
-
 impl From<MonochromeSprite> for Primitive {
     fn from(sprite: MonochromeSprite) -> Self {
         Primitive::MonochromeSprite(sprite)
     }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug)]
 #[repr(C)]
 pub(crate) struct PolychromeSprite {
     pub order: DrawOrder,
@@ -687,30 +638,14 @@ pub(crate) struct PolychromeSprite {
     pub corner_radii: Corners<ScaledPixels>,
     pub tile: AtlasTile,
 }
-impl Eq for PolychromeSprite {}
-
-impl Ord for PolychromeSprite {
-    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        match self.order.cmp(&other.order) {
-            std::cmp::Ordering::Equal => self.tile.tile_id.cmp(&other.tile.tile_id),
-            order => order,
-        }
-    }
-}
-
-impl PartialOrd for PolychromeSprite {
-    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-        Some(self.cmp(other))
-    }
-}
 
 impl From<PolychromeSprite> for Primitive {
     fn from(sprite: PolychromeSprite) -> Self {
         Primitive::PolychromeSprite(sprite)
     }
 }
 
-#[derive(Clone, Debug, Eq, PartialEq)]
+#[derive(Clone, Debug)]
 pub(crate) struct PaintSurface {
     pub order: DrawOrder,
     pub bounds: Bounds<ScaledPixels>,
@@ -719,18 +654,6 @@ pub(crate) struct PaintSurface {
     pub image_buffer: media::core_video::CVImageBuffer,
 }
 
-impl Ord for PaintSurface {
-    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        self.order.cmp(&other.order)
-    }
-}
-
-impl PartialOrd for PaintSurface {
-    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-        Some(self.cmp(other))
-    }
-}
-
 impl From<PaintSurface> for Primitive {
     fn from(surface: PaintSurface) -> Self {
         Primitive::Surface(surface)
@@ -859,26 +782,6 @@ impl Path<Pixels> {
     }
 }
 
-impl Eq for Path<ScaledPixels> {}
-
-impl PartialEq for Path<ScaledPixels> {
-    fn eq(&self, other: &Self) -> bool {
-        self.order == other.order
-    }
-}
-
-impl Ord for Path<ScaledPixels> {
-    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        self.order.cmp(&other.order)
-    }
-}
-
-impl PartialOrd for Path<ScaledPixels> {
-    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-        Some(self.cmp(other))
-    }
-}
-
 impl From<Path<ScaledPixels>> for Primitive {
     fn from(path: Path<ScaledPixels>) -> Self {
         Primitive::Path(path)