Draft (very) basic incremental rendering for `iced_tiny_skia`

10 files changed, 286 insertions, 92 deletions

diff --git a/Cargo.toml b/Cargo.toml
index 38c35f43..854dc8a0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -86,3 +86,6 @@ incremental = false
 opt-level = 3
 overflow-checks = false
 strip = "debuginfo"
+
+[patch.crates-io]
+tiny-skia = { version = "0.8", git = "https://github.com/hecrj/tiny-skia.git", rev = "213890dcbb3754d51533f5b558d9f5ffa3bf6da1" }
diff --git a/core/src/image.rs b/core/src/image.rs
index 70fbade0..618235ef 100644
--- a/core/src/image.rs
+++ b/core/src/image.rs
@@ -6,7 +6,7 @@ use std::path::PathBuf;
 use std::sync::Arc;
 
 /// A handle of some image data.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Handle {
     id: u64,
     data: Data,
@@ -156,6 +156,34 @@ impl std::fmt::Debug for Data {
     }
 }
 
+impl PartialEq for Data {
+    fn eq(&self, other: &Self) -> bool {
+        match (self, other) {
+            (Self::Path(a), Self::Path(b)) => a == b,
+            (Self::Bytes(a), Self::Bytes(b)) => a.as_ref() == b.as_ref(),
+            (
+                Self::Rgba {
+                    width: width_a,
+                    height: height_a,
+                    pixels: pixels_a,
+                },
+                Self::Rgba {
+                    width: width_b,
+                    height: height_b,
+                    pixels: pixels_b,
+                },
+            ) => {
+                width_a == width_b
+                    && height_a == height_b
+                    && pixels_a.as_ref() == pixels_b.as_ref()
+            }
+            _ => false,
+        }
+    }
+}
+
+impl Eq for Data {}
+
 /// A [`Renderer`] that can render raster graphics.
 ///
 /// [renderer]: crate::renderer
diff --git a/core/src/rectangle.rs b/core/src/rectangle.rs
index 4fe91519..5cdcbe78 100644
--- a/core/src/rectangle.rs
+++ b/core/src/rectangle.rs
@@ -100,6 +100,30 @@ impl Rectangle<f32> {
         }
     }
 
+    /// Returns whether the [`Rectangle`] intersects with the given one.
+    pub fn intersects(&self, other: &Self) -> bool {
+        self.intersection(other).is_some()
+    }
+
+    /// Computes the union with the given [`Rectangle`].
+    pub fn union(&self, other: &Self) -> Self {
+        let x = self.x.min(other.x);
+        let y = self.y.min(other.y);
+
+        let lower_right_x = (self.x + self.width).max(other.x + other.width);
+        let lower_right_y = (self.y + self.height).max(other.y + other.height);
+
+        let width = lower_right_x - x;
+        let height = lower_right_y - y;
+
+        Rectangle {
+            x,
+            y,
+            width,
+            height,
+        }
+    }
+
     /// Snaps the [`Rectangle`] to __unsigned__ integer coordinates.
     pub fn snap(self) -> Rectangle<u32> {
         Rectangle {
@@ -109,6 +133,16 @@ impl Rectangle<f32> {
             height: self.height as u32,
         }
     }
+
+    /// Expands the [`Rectangle`] a given amount.
+    pub fn expand(self, amount: f32) -> Self {
+        Self {
+            x: self.x - amount,
+            y: self.y - amount,
+            width: self.width + amount * 2.0,
+            height: self.height + amount * 2.0,
+        }
+    }
 }
 
 impl std::ops::Mul<f32> for Rectangle<f32> {
diff --git a/core/src/svg.rs b/core/src/svg.rs
index 9b98877a..54e9434e 100644
--- a/core/src/svg.rs
+++ b/core/src/svg.rs
@@ -7,7 +7,7 @@ use std::path::PathBuf;
 use std::sync::Arc;
 
 /// A handle of Svg data.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Handle {
     id: u64,
     data: Arc<Data>,
@@ -57,7 +57,7 @@ impl Hash for Handle {
 }
 
 /// The data of a vectorial image.
-#[derive(Clone, Hash)]
+#[derive(Clone, Hash, PartialEq, Eq)]
 pub enum Data {
     /// File data
     Path(PathBuf),
diff --git a/graphics/src/primitive.rs b/graphics/src/primitive.rs
index 195b62da..bbf300b0 100644
--- a/graphics/src/primitive.rs
+++ b/graphics/src/primitive.rs
@@ -7,7 +7,7 @@ use bytemuck::{Pod, Zeroable};
 use std::sync::Arc;
 
 /// A rendering primitive.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 #[non_exhaustive]
 pub enum Primitive {
     /// A text primitive
@@ -147,10 +147,153 @@ impl Primitive {
             content: Box::new(self),
         }
     }
+
+    pub fn bounds(&self) -> Rectangle {
+        match self {
+            Self::Text {
+                bounds,
+                horizontal_alignment,
+                vertical_alignment,
+                ..
+            } => {
+                let mut bounds = *bounds;
+
+                bounds.x = match horizontal_alignment {
+                    alignment::Horizontal::Left => bounds.x,
+                    alignment::Horizontal::Center => {
+                        bounds.x - bounds.width / 2.0
+                    }
+                    alignment::Horizontal::Right => bounds.x - bounds.width,
+                };
+
+                bounds.y = match vertical_alignment {
+                    alignment::Vertical::Top => bounds.y,
+                    alignment::Vertical::Center => {
+                        bounds.y - bounds.height / 2.0
+                    }
+                    alignment::Vertical::Bottom => bounds.y - bounds.height,
+                };
+
+                bounds.expand(1.0)
+            }
+            Self::Quad { bounds, .. }
+            | Self::Image { bounds, .. }
+            | Self::Svg { bounds, .. }
+            | Self::Clip { bounds, .. } => bounds.expand(1.0),
+            Self::SolidMesh { size, .. } | Self::GradientMesh { size, .. } => {
+                Rectangle::with_size(*size)
+            }
+            #[cfg(feature = "tiny-skia")]
+            Self::Fill { path, .. } | Self::Stroke { path, .. } => {
+                let bounds = path.bounds();
+
+                Rectangle {
+                    x: bounds.x(),
+                    y: bounds.y(),
+                    width: bounds.width(),
+                    height: bounds.height(),
+                }
+                .expand(1.0)
+            }
+            Self::Group { primitives } => primitives
+                .iter()
+                .map(Self::bounds)
+                .fold(Rectangle::with_size(Size::ZERO), |a, b| {
+                    Rectangle::union(&a, &b)
+                }),
+            Self::Translate {
+                translation,
+                content,
+            } => content.bounds() + *translation,
+            Self::Cache { content } => content.bounds(),
+        }
+    }
+
+    pub fn damage(&self, other: &Self) -> Vec<Rectangle> {
+        match (self, other) {
+            (
+                Primitive::Group {
+                    primitives: primitives_a,
+                },
+                Primitive::Group {
+                    primitives: primitives_b,
+                },
+            ) => return Self::damage_list(primitives_a, primitives_b),
+            (
+                Primitive::Clip {
+                    bounds: bounds_a,
+                    content: content_a,
+                },
+                Primitive::Clip {
+                    bounds: bounds_b,
+                    content: content_b,
+                },
+            ) => {
+                if bounds_a == bounds_b {
+                    return content_a.damage(content_b);
+                } else {
+                    return vec![*bounds_a, *bounds_b];
+                }
+            }
+            (
+                Primitive::Translate {
+                    translation: translation_a,
+                    content: content_a,
+                },
+                Primitive::Translate {
+                    translation: translation_b,
+                    content: content_b,
+                },
+            ) => {
+                if translation_a == translation_b {
+                    return content_a.damage(content_b);
+                }
+            }
+            (
+                Primitive::Cache { content: content_a },
+                Primitive::Cache { content: content_b },
+            ) => {
+                if Arc::ptr_eq(content_a, content_b) {
+                    return vec![];
+                }
+            }
+            _ if self == other => return vec![],
+            _ => {}
+        }
+
+        let bounds_a = self.bounds();
+        let bounds_b = other.bounds();
+
+        if bounds_a == bounds_b {
+            vec![bounds_a]
+        } else {
+            vec![bounds_a, bounds_b]
+        }
+    }
+
+    pub fn damage_list(previous: &[Self], current: &[Self]) -> Vec<Rectangle> {
+        let damage =
+            previous.iter().zip(current).flat_map(|(a, b)| a.damage(b));
+
+        if previous.len() == current.len() {
+            damage.collect()
+        } else {
+            let (smaller, bigger) = if previous.len() < current.len() {
+                (previous, current)
+            } else {
+                (current, previous)
+            };
+
+            // Extend damage by the added/removed primitives
+            damage
+                .chain(bigger[smaller.len()..].iter().map(Primitive::bounds))
+                .collect()
+        }
+    }
 }
 
 /// A set of [`Vertex2D`] and indices representing a list of triangles.
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct Mesh2D<T> {
     /// The vertices of the mesh
     pub vertices: Vec<T>,
@@ -162,7 +305,7 @@ pub struct Mesh2D<T> {
 }
 
 /// A two-dimensional vertex.
-#[derive(Copy, Clone, Debug, Zeroable, Pod)]
+#[derive(Copy, Clone, Debug, PartialEq, Zeroable, Pod)]
 #[repr(C)]
 pub struct Vertex2D {
     /// The vertex position in 2D space.
@@ -170,7 +313,7 @@ pub struct Vertex2D {
 }
 
 /// A two-dimensional vertex with a color.
-#[derive(Copy, Clone, Debug, Zeroable, Pod)]
+#[derive(Copy, Clone, Debug, PartialEq, Zeroable, Pod)]
 #[repr(C)]
 pub struct ColoredVertex2D {
     /// The vertex position in 2D space.
diff --git a/graphics/src/renderer.rs b/graphics/src/renderer.rs
index 7bc462ef..23e594be 100644
--- a/graphics/src/renderer.rs
+++ b/graphics/src/renderer.rs
@@ -32,7 +32,7 @@ impl<B: Backend, T> Renderer<B, T> {
         }
     }
 
-    /// Returns the [`Backend`] of the [`Renderer`].
+    /// Returns a reference to the [`Backend`] of the [`Renderer`].
     pub fn backend(&self) -> &B {
         &self.backend
     }
diff --git a/runtime/src/debug/basic.rs b/runtime/src/debug/basic.rs
index 32f725a1..e9be4c84 100644
--- a/runtime/src/debug/basic.rs
+++ b/runtime/src/debug/basic.rs
@@ -129,7 +129,7 @@ impl Debug {
 
     pub fn render_finished(&mut self) {
         self.render_durations
-            .push(time::Instant::now() - self.render_start);
+            .push(dbg!(time::Instant::now() - self.render_start));
     }
 
     pub fn log_message<Message: std::fmt::Debug>(&mut self, message: &Message) {
diff --git a/tiny_skia/src/backend.rs b/tiny_skia/src/backend.rs
index 58076b84..fe84f83b 100644
--- a/tiny_skia/src/backend.rs
+++ b/tiny_skia/src/backend.rs
@@ -17,6 +17,9 @@ pub struct Backend {
 
     #[cfg(feature = "svg")]
     vector_pipeline: crate::vector::Pipeline,
+
+    last_primitives: Vec<Primitive>,
+    last_background_color: Color,
 }
 
 impl Backend {
@@ -31,6 +34,9 @@ impl Backend {
 
             #[cfg(feature = "svg")]
             vector_pipeline: crate::vector::Pipeline::new(),
+
+            last_primitives: Vec::new(),
+            last_background_color: Color::BLACK,
         }
     }
 
@@ -43,10 +49,48 @@ impl Backend {
         background_color: Color,
         overlay: &[T],
     ) {
-        pixels.fill(into_color(background_color));
+        let damage = if self.last_background_color == background_color {
+            Primitive::damage_list(&self.last_primitives, primitives)
+        } else {
+            vec![Rectangle::with_size(viewport.logical_size())]
+        };
+
+        if damage.is_empty() {
+            return;
+        }
+
+        self.last_primitives = primitives.to_vec();
+        self.last_background_color = background_color;
 
         let scale_factor = viewport.scale_factor() as f32;
 
+        dbg!(&damage);
+
+        for region in &damage {
+            let region = *region * scale_factor;
+
+            pixels.fill_path(
+                &tiny_skia::PathBuilder::from_rect(
+                    tiny_skia::Rect::from_xywh(
+                        region.x,
+                        region.y,
+                        region.width.min(viewport.physical_width() as f32),
+                        region.height.min(viewport.physical_height() as f32),
+                    )
+                    .expect("Create damage rectangle"),
+                ),
+                &tiny_skia::Paint {
+                    shader: tiny_skia::Shader::SolidColor(into_color(
+                        background_color,
+                    )),
+                    ..Default::default()
+                },
+                tiny_skia::FillRule::default(),
+                tiny_skia::Transform::identity(),
+                None,
+            );
+        }
+
         for primitive in primitives {
             self.draw_primitive(
                 primitive,
@@ -55,6 +99,7 @@ impl Backend {
                 None,
                 scale_factor,
                 Vector::ZERO,
+                &damage,
             );
         }
 
@@ -81,6 +126,7 @@ impl Backend {
                 None,
                 scale_factor,
                 Vector::ZERO,
+                &[],
             );
         }
 
@@ -101,6 +147,7 @@ impl Backend {
         clip_bounds: Option<Rectangle>,
         scale_factor: f32,
         translation: Vector,
+        damage: &[Rectangle],
     ) {
         match primitive {
             Primitive::Quad {
@@ -110,6 +157,10 @@ impl Backend {
                 border_width,
                 border_color,
             } => {
+                if !damage.iter().any(|damage| damage.intersects(bounds)) {
+                    return;
+                }
+
                 let transform = tiny_skia::Transform::from_translate(
                     translation.x,
                     translation.y,
@@ -165,6 +216,13 @@ impl Backend {
                 horizontal_alignment,
                 vertical_alignment,
             } => {
+                if !damage
+                    .iter()
+                    .any(|damage| damage.intersects(&primitive.bounds()))
+                {
+                    return;
+                }
+
                 self.text_pipeline.draw(
                     content,
                     (*bounds + translation) * scale_factor,
@@ -179,6 +237,10 @@ impl Backend {
             }
             #[cfg(feature = "image")]
             Primitive::Image { handle, bounds } => {
+                if !damage.iter().any(|damage| damage.intersects(bounds)) {
+                    return;
+                }
+
                 let transform = tiny_skia::Transform::from_translate(
                     translation.x,
                     translation.y,
@@ -248,6 +310,7 @@ impl Backend {
                         clip_bounds,
                         scale_factor,
                         translation,
+                        damage,
                     );
                 }
             }
@@ -262,6 +325,7 @@ impl Backend {
                     clip_bounds,
                     scale_factor,
                     translation + *offset,
+                    damage,
                 );
             }
             Primitive::Clip { bounds, content } => {
@@ -284,6 +348,7 @@ impl Backend {
                     Some(bounds),
                     scale_factor,
                     translation,
+                    damage,
                 );
 
                 if let Some(bounds) = clip_bounds {
@@ -300,6 +365,7 @@ impl Backend {
                     clip_bounds,
                     scale_factor,
                     translation,
+                    damage,
                 );
             }
             Primitive::SolidMesh { .. } | Primitive::GradientMesh { .. } => {
diff --git a/tiny_skia/src/primitive.rs b/tiny_skia/src/primitive.rs
deleted file mode 100644
index 22daaedc..00000000
--- a/tiny_skia/src/primitive.rs
+++ /dev/null
@@ -1,82 +0,0 @@
-use crate::{Rectangle, Vector};
-
-use std::sync::Arc;
-
-#[derive(Debug, Clone)]
-pub enum Primitive {
-    /// A group of primitives
-    Group {
-        /// The primitives of the group
-        primitives: Vec<Primitive>,
-    },
-    /// A clip primitive
-    Clip {
-        /// The bounds of the clip
-        bounds: Rectangle,
-        /// The content of the clip
-        content: Box<Primitive>,
-    },
-    /// A primitive that applies a translation
-    Translate {
-        /// The translation vector
-        translation: Vector,
-
-        /// The primitive to translate
-        content: Box<Primitive>,
-    },
-    /// A cached primitive.
-    ///
-    /// This can be useful if you are implementing a widget where primitive
-    /// generation is expensive.
-    Cached {
-        /// The cached primitive
-        cache: Arc<Primitive>,
-    },
-    /// A basic primitive.
-    Basic(iced_graphics::Primitive),
-}
-
-impl iced_graphics::backend::Primitive for Primitive {
-    fn translate(self, translation: Vector) -> Self {
-        Self::Translate {
-            translation,
-            content: Box::new(self),
-        }
-    }
-
-    fn clip(self, bounds: Rectangle) -> Self {
-        Self::Clip {
-            bounds,
-            content: Box::new(self),
-        }
-    }
-}
-
-#[derive(Debug, Clone, Default)]
-pub struct Recording(pub(crate) Vec<Primitive>);
-
-impl iced_graphics::backend::Recording for Recording {
-    type Primitive = Primitive;
-
-    fn push(&mut self, primitive: Primitive) {
-        self.0.push(primitive);
-    }
-
-    fn push_basic(&mut self, basic: iced_graphics::Primitive) {
-        self.0.push(Primitive::Basic(basic));
-    }
-
-    fn group(self) -> Self::Primitive {
-        Primitive::Group { primitives: self.0 }
-    }
-
-    fn clear(&mut self) {
-        self.0.clear();
-    }
-}
-
-impl Recording {
-    pub fn primitives(&self) -> &[Primitive] {
-        &self.0
-    }
-}
diff --git a/widget/src/text_input.rs b/widget/src/text_input.rs
index d066109a..4f018284 100644
--- a/widget/src/text_input.rs
+++ b/widget/src/text_input.rs
@@ -953,6 +953,8 @@ pub fn draw<Renderer>(
     let render = |renderer: &mut Renderer| {
         if let Some((cursor, color)) = cursor {
             renderer.fill_quad(cursor, color);
+        } else {
+            renderer.with_translation(Vector::ZERO, |_| {});
         }
 
         renderer.fill_text(Text {