Cache loaded fonts and glyph outlines.

Approximately a 70% CPU time improvement on the NanoVG demo.

Cargo.lock

@@ -285,6 +285,7 @@ dependencies = [
  "gl 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "image 0.23.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "jemallocator 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "pathfinder_canvas 0.1.0",
  "pathfinder_color 0.1.0",
  "pathfinder_content 0.1.0",

canvas/src/lib.rs

@@ -94,16 +94,18 @@ impl Canvas {
         self.scene
     }
 
-    pub fn get_context_2d(self, font_context: CanvasFontContext) -> CanvasRenderingContext2D {
+    pub fn get_context_2d(self, canvas_font_context: CanvasFontContext)
+                          -> CanvasRenderingContext2D {
         #[cfg(feature = "pf-text")]
-        let default_font_collection = font_context.default_font_collection.clone();
+        let default_font_collection =
+            canvas_font_context.0.borrow().default_font_collection.clone();
         #[cfg(not(feature = "pf-text"))]
         let default_font_collection = Arc::new(FontCollection);
         CanvasRenderingContext2D {
             canvas: self,
             current_state: State::default(default_font_collection),
             saved_states: vec![],
-            font_context,
+            canvas_font_context,
         }
     }
 
@@ -118,7 +120,7 @@ pub struct CanvasRenderingContext2D {
     current_state: State,
     saved_states: Vec<State>,
     #[allow(dead_code)]
-    font_context: CanvasFontContext,
+    canvas_font_context: CanvasFontContext,
 }
 
 impl CanvasRenderingContext2D {
@@ -134,11 +136,6 @@ impl CanvasRenderingContext2D {
         self.canvas
     }
 
-    #[inline]
-    pub fn font_context(&self) -> CanvasFontContext {
-        self.font_context.clone()
-    }
-
     // Drawing rectangles
 
     #[inline]

canvas/src/text.rs

@@ -21,8 +21,10 @@ use pathfinder_geometry::transform2d::Transform2F;
 use pathfinder_geometry::util;
 use pathfinder_geometry::vector::{Vector2F, vec2f};
 use pathfinder_renderer::paint::PaintId;
-use pathfinder_text::{SceneExt, TextRenderMode};
+use pathfinder_text::{FontContext, FontRenderOptions, TextRenderMode};
 use skribo::{FontCollection, FontFamily, FontRef, Layout, TextStyle};
+use std::cell::RefCell;
+use std::rc::Rc;
 use std::sync::Arc;
 
 impl CanvasRenderingContext2D {
@@ -51,14 +53,22 @@ impl CanvasRenderingContext2D {
         let clip_path = self.current_state.clip_path;
         let blend_mode = self.current_state.global_composite_operation.to_blend_mode();
 
-        drop(self.canvas.scene.push_layout(&layout,
-                                           &TextStyle { size: self.current_state.font_size },
-                                           &(transform * self.current_state.transform),
-                                           TextRenderMode::Fill,
-                                           HintingOptions::None,
-                                           clip_path,
-                                           blend_mode,
-                                           paint_id));
+        // TODO(pcwalton): Report errors.
+        drop(self.canvas_font_context
+                 .0
+                 .borrow_mut()
+                 .font_context
+                 .push_layout(&mut self.canvas.scene,
+                              &layout,
+                              &TextStyle { size: self.current_state.font_size },
+                              &FontRenderOptions {
+                                  transform: transform * self.current_state.transform,
+                                  render_mode: TextRenderMode::Fill,
+                                  hinting_options: HintingOptions::None,
+                                  clip_path,
+                                  blend_mode,
+                                  paint_id,
+                              }));
     }
 
     fn fill_or_stroke_text(&mut self,
@@ -75,14 +85,21 @@ impl CanvasRenderingContext2D {
         let transform = self.current_state.transform * Transform2F::from_translation(position);
 
         // TODO(pcwalton): Report errors.
-        drop(self.canvas.scene.push_layout(&layout,
-                                           &TextStyle { size: self.current_state.font_size },
-                                           &transform,
-                                           render_mode,
-                                           HintingOptions::None,
-                                           clip_path,
-                                           blend_mode,
-                                           paint_id));
+        drop(self.canvas_font_context
+                 .0
+                 .borrow_mut()
+                 .font_context
+                 .push_layout(&mut self.canvas.scene,
+                              &layout,
+                              &TextStyle { size: self.current_state.font_size },
+                              &FontRenderOptions {
+                                  transform,
+                                  render_mode,
+                                  hinting_options: HintingOptions::None,
+                                  clip_path,
+                                  blend_mode,
+                                  paint_id,
+                              }));
     }
 
     fn layout_text(&self, string: &str) -> Layout {
@@ -100,7 +117,7 @@ impl CanvasRenderingContext2D {
 
     #[inline]
     pub fn set_font<FC>(&mut self, font_collection: FC) where FC: IntoFontCollection {
-        let font_collection = font_collection.into_font_collection(&self.font_context);
+        let font_collection = font_collection.into_font_collection(&self.canvas_font_context);
         self.current_state.font_collection = font_collection; 
     }
 
@@ -179,7 +196,10 @@ pub struct TextMetrics {
 
 #[cfg(feature = "pf-text")]
 #[derive(Clone)]
-pub struct CanvasFontContext {
+pub struct CanvasFontContext(pub(crate) Rc<RefCell<CanvasFontContextData>>);
+
+pub(super) struct CanvasFontContextData {
+    pub(super) font_context: FontContext<Font>,
     #[allow(dead_code)]
     pub(super) font_source: Arc<dyn Source>,
     #[allow(dead_code)]
@@ -196,10 +216,11 @@ impl CanvasFontContext {
             }
         }
 
-        CanvasFontContext {
+        CanvasFontContext(Rc::new(RefCell::new(CanvasFontContextData {
             font_source,
             default_font_collection: Arc::new(default_font_collection),
-        }
+            font_context: FontContext::new(),
+        })))
     }
 
     /// A convenience method to create a font context with the system source.
@@ -212,6 +233,18 @@ impl CanvasFontContext {
     pub fn from_fonts<I>(fonts: I) -> CanvasFontContext where I: Iterator<Item = Handle> {
         CanvasFontContext::new(Arc::new(MemSource::from_fonts(fonts).unwrap()))
     }
+
+    fn get_font_by_postscript_name(&self, postscript_name: &str) -> Font {
+        let this = self.0.borrow();
+        if let Some(cached_font) = this.font_context.get_cached_font(postscript_name) {
+            return (*cached_font).clone();
+        }
+        this.font_source
+            .select_by_postscript_name(postscript_name)
+            .expect("Couldn't find a font with that PostScript name!")
+            .load()
+            .expect("Failed to load the font!")
+    }
 }
 
 // Text layout utilities
@@ -413,6 +446,7 @@ impl IntoFontCollection for Vec<FontFamily> {
     }
 }
 
+/*
 impl IntoFontCollection for Handle {
     #[inline]
     fn into_font_collection(self, context: &CanvasFontContext) -> Arc<FontCollection> {
@@ -422,15 +456,18 @@ impl IntoFontCollection for Handle {
 
 impl<'a> IntoFontCollection for &'a [Handle] {
     #[inline]
-    fn into_font_collection(self, _: &CanvasFontContext) -> Arc<FontCollection> {
+    fn into_font_collection(self, context: &CanvasFontContext) -> Arc<FontCollection> {
         let mut font_collection = FontCollection::new();
         for handle in self {
+            let postscript_name = handle.postscript_name();
+
             let font = handle.load().expect("Failed to load the font!");
             font_collection.add_family(FontFamily::new_from_font(font));
         }
         Arc::new(font_collection)
     }
 }
+*/
 
 impl IntoFontCollection for Font {
     #[inline]
@@ -453,10 +490,7 @@ impl<'a> IntoFontCollection for &'a [Font] {
 impl<'a> IntoFontCollection for &'a str {
     #[inline]
     fn into_font_collection(self, context: &CanvasFontContext) -> Arc<FontCollection> {
-        context.font_source
-               .select_by_postscript_name(self)
-               .expect("Couldn't find a font with that PostScript name!")
-               .into_font_collection(context)
+        context.get_font_by_postscript_name(self).into_font_collection(context)
     }
 }
 
@@ -465,11 +499,7 @@ impl<'a, 'b> IntoFontCollection for &'a [&'b str] {
     fn into_font_collection(self, context: &CanvasFontContext) -> Arc<FontCollection> {
         let mut font_collection = FontCollection::new();
         for postscript_name in self {
-            let font = context.font_source
-                              .select_by_postscript_name(postscript_name)
-                              .expect("Failed to find a font with that PostScript name!")
-                              .load()
-                              .expect("Failed to load the font!");
+            let font = context.get_font_by_postscript_name(postscript_name);
             font_collection.add_family(FontFamily::new_from_font(font));
         }
         Arc::new(font_collection)

examples/canvas_nanovg/Cargo.toml

@@ -16,6 +16,10 @@ version = "0.23"
 default-features = false
 features = ["png"]
 
+[dependencies.log]
+version = "0.4"
+features = ["release_max_level_info"]
+
 [dependencies.pathfinder_canvas]
 path = "../../canvas"
 features = ["pf-text"]

examples/canvas_nanovg/src/main.rs

@@ -1544,7 +1544,8 @@ fn main() {
         gpu_graph.render(&mut context, vec2f(415.0, 5.0));
 
         // Render the canvas to screen.
-        let scene = SceneProxy::from_scene(context.into_canvas().into_scene(), RayonExecutor);
+        let canvas = context.into_canvas();
+        let scene = SceneProxy::from_scene(canvas.into_scene(), RayonExecutor);
         scene.build_and_render(&mut renderer, BuildOptions::default());
         window.gl_swap_window();
 

text/src/lib.rs

@@ -11,138 +11,182 @@
 use font_kit::error::GlyphLoadingError;
 use font_kit::hinting::HintingOptions;
 use font_kit::loader::Loader;
+use font_kit::loaders::default::Font as DefaultLoader;
 use font_kit::outline::OutlineSink;
 use pathfinder_content::effects::BlendMode;
 use pathfinder_content::outline::{Contour, Outline};
 use pathfinder_content::stroke::{OutlineStrokeToFill, StrokeStyle};
 use pathfinder_geometry::line_segment::LineSegment2F;
 use pathfinder_geometry::transform2d::Transform2F;
-use pathfinder_geometry::vector::Vector2F;
+use pathfinder_geometry::vector::{Vector2F, vec2f};
 use pathfinder_renderer::paint::PaintId;
 use pathfinder_renderer::scene::{ClipPathId, DrawPath, Scene};
 use skribo::{FontCollection, Layout, TextStyle};
+use std::collections::HashMap;
 use std::mem;
 
-// FIXME(pcwalton): Too many parameters!
-pub trait SceneExt {
-    // TODO(pcwalton): Support stroked glyphs.
-    fn push_glyph<F>(&mut self,
-                     font: &F,
-                     glyph_id: u32,
-                     transform: &Transform2F,
-                     render_mode: TextRenderMode,
-                     hinting_options: HintingOptions,
-                     clip_path: Option<ClipPathId>,
-                     blend_mode: BlendMode,
-                     paint_id: PaintId)
-                     -> Result<(), GlyphLoadingError>
-                     where F: Loader;
-
-    fn push_layout(&mut self,
-                   layout: &Layout,
-                   style: &TextStyle,
-                   transform: &Transform2F,
-                   render_mode: TextRenderMode,
-                   hinting_options: HintingOptions,
-                   clip_path: Option<ClipPathId>,
-                   blend_mode: BlendMode,
-                   paint_id: PaintId)
-                   -> Result<(), GlyphLoadingError>;
-
-    fn push_text(&mut self,
-                 text: &str,
-                 style: &TextStyle,
-                 collection: &FontCollection,
-                 transform: &Transform2F,
-                 render_mode: TextRenderMode,
-                 hinting_options: HintingOptions,
-                 clip_path: Option<ClipPathId>,
-                 blend_mode: BlendMode,
-                 paint_id: PaintId)
-                 -> Result<(), GlyphLoadingError>;
+#[derive(Clone)]
+pub struct FontContext<F> where F: Loader {
+    font_info: HashMap<String, FontInfo<F>>, 
 }
 
-impl SceneExt for Scene {
-    #[inline]
-    fn push_glyph<F>(&mut self,
-                     font: &F,
-                     glyph_id: u32,
-                     transform: &Transform2F,
-                     render_mode: TextRenderMode,
-                     hinting_options: HintingOptions,
-                     clip_path: Option<ClipPathId>,
-                     blend_mode: BlendMode,
-                     paint_id: PaintId)
-                     -> Result<(), GlyphLoadingError>
-                     where F: Loader {
-        let mut outline_builder = OutlinePathBuilder::new(transform);
-        font.outline(glyph_id, hinting_options, &mut outline_builder)?;
-        let mut outline = outline_builder.build();
+#[derive(Clone)]
+struct FontInfo<F> where F: Loader {
+    font: F,
+    outline_cache: HashMap<GlyphId, Outline>,
+}
 
-        if let TextRenderMode::Stroke(stroke_style) = render_mode {
+#[derive(Clone, Copy)]
+pub struct FontRenderOptions {
+    pub transform: Transform2F,
+    pub render_mode: TextRenderMode,
+    pub hinting_options: HintingOptions,
+    pub clip_path: Option<ClipPathId>,
+    pub blend_mode: BlendMode,
+    pub paint_id: PaintId,
+}
+
+impl Default for FontRenderOptions {
+    #[inline]
+    fn default() -> FontRenderOptions {
+        FontRenderOptions {
+            transform: Transform2F::default(),
+            render_mode: TextRenderMode::Fill,
+            hinting_options: HintingOptions::None,
+            clip_path: None,
+            blend_mode: BlendMode::SrcOver,
+            paint_id: PaintId(0),
+        }
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Debug, Eq, Hash)]
+pub struct GlyphId(pub u32);
+
+impl<F> FontContext<F> where F: Loader {
+    #[inline]
+    pub fn new() -> FontContext<F> {
+        FontContext { font_info: HashMap::new() }
+    }
+
+    pub fn push_glyph(&mut self,
+                      scene: &mut Scene,
+                      font: &F,
+                      glyph_id: GlyphId,
+                      render_options: &FontRenderOptions)
+                      -> Result<(), GlyphLoadingError> {
+        let font_key = font.postscript_name();
+        let metrics = font.metrics();
+
+        // Insert the font into the cache if needed.
+        if let Some(ref font_key) = font_key {
+            if !self.font_info.contains_key(&*font_key) {
+                self.font_info.insert((*font_key).clone(), FontInfo::new((*font).clone()));
+            }
+        }
+
+        // See if we have a cached outline.
+        //
+        // TODO(pcwalton): Cache hinted outlines too.
+        let mut cached_outline = None;
+        let can_cache_outline = font_key.is_some() &&
+            render_options.hinting_options == HintingOptions::None;
+        if can_cache_outline {
+            if let Some(ref font_info) = self.font_info.get(&*font_key.as_ref().unwrap()) {
+                if let Some(ref outline) = font_info.outline_cache.get(&glyph_id) {
+                    cached_outline = Some((*outline).clone());
+                }
+            }
+        }
+
+        let mut outline = match cached_outline {
+            Some(mut cached_outline) => {
+                let scale = 1.0 / metrics.units_per_em as f32;
+                cached_outline.transform(&(render_options.transform *
+                                           Transform2F::from_scale(scale)));
+                cached_outline
+            }
+            None => {
+                let transform = if can_cache_outline {
+                    Transform2F::from_scale(metrics.units_per_em as f32)
+                } else {
+                    render_options.transform
+                };
+                let mut outline_builder = OutlinePathBuilder::new(&transform);
+                font.outline(glyph_id.0, render_options.hinting_options, &mut outline_builder)?;
+                let mut outline = outline_builder.build();
+                if can_cache_outline {
+                    let font_key = font_key.as_ref().unwrap();
+                    let font_info = self.font_info.get_mut(&*font_key).unwrap();
+                    font_info.outline_cache.insert(glyph_id, outline.clone());
+                    let scale = 1.0 / metrics.units_per_em as f32;
+                    outline.transform(&(render_options.transform *
+                                        Transform2F::from_scale(scale)));
+                }
+                outline
+            }
+        };
+
+        if let TextRenderMode::Stroke(stroke_style) = render_options.render_mode {
             let mut stroke_to_fill = OutlineStrokeToFill::new(&outline, stroke_style);
             stroke_to_fill.offset();
             outline = stroke_to_fill.into_outline();
         }
 
-        let mut path = DrawPath::new(outline, paint_id);
-        path.set_clip_path(clip_path);
-        path.set_blend_mode(blend_mode);
+        let mut path = DrawPath::new(outline, render_options.paint_id);
+        path.set_clip_path(render_options.clip_path);
+        path.set_blend_mode(render_options.blend_mode);
 
-        self.push_path(path);
+        scene.push_path(path);
         Ok(())
     }
 
-    fn push_layout(&mut self,
-                   layout: &Layout,
-                   style: &TextStyle,
-                   transform: &Transform2F,
-                   render_mode: TextRenderMode,
-                   hinting_options: HintingOptions,
-                   clip_path: Option<ClipPathId>,
-                   blend_mode: BlendMode,
-                   paint_id: PaintId)
-                   -> Result<(), GlyphLoadingError> {
+    /// Attempts to look up a font in the font cache.
+    #[inline]
+    pub fn get_cached_font(&self, postscript_name: &str) -> Option<&F> {
+        self.font_info.get(postscript_name).map(|font_info| &font_info.font)
+    }
+}
+
+impl FontContext<DefaultLoader> {
+    pub fn push_layout(&mut self,
+                       scene: &mut Scene,
+                       layout: &Layout,
+                       style: &TextStyle,
+                       render_options: &FontRenderOptions)
+                       -> Result<(), GlyphLoadingError> {
         for glyph in &layout.glyphs {
             let offset = glyph.offset;
             let font = &*glyph.font.font;
             // FIXME(pcwalton): Cache this!
             let scale = style.size / (font.metrics().units_per_em as f32);
-            let scale = Vector2F::new(scale, -scale);
-            let transform = *transform * Transform2F::from_scale(scale).translate(offset);
-            self.push_glyph(font,
-                            glyph.glyph_id,
-                            &transform,
-                            render_mode,
-                            hinting_options,
-                            clip_path,
-                            blend_mode,
-                            paint_id)?;
+            let scale = vec2f(scale, -scale);
+            let render_options = FontRenderOptions {
+                transform: render_options.transform *
+                    Transform2F::from_scale(scale).translate(offset),
+                ..*render_options
+            };
+            self.push_glyph(scene, font, GlyphId(glyph.glyph_id), &render_options)?;
         }
         Ok(())
     }
 
     #[inline]
-    fn push_text(&mut self,
-                 text: &str,
-                 style: &TextStyle,
-                 collection: &FontCollection,
-                 transform: &Transform2F,
-                 render_mode: TextRenderMode,
-                 hinting_options: HintingOptions,
-                 clip_path: Option<ClipPathId>,
-                 blend_mode: BlendMode,
-                 paint_id: PaintId)
-                 -> Result<(), GlyphLoadingError> {
+    pub fn push_text(&mut self,
+                     scene: &mut Scene,
+                     text: &str,
+                     style: &TextStyle,
+                     collection: &FontCollection,
+                     render_options: &FontRenderOptions)
+                     -> Result<(), GlyphLoadingError> {
         let layout = skribo::layout(style, collection, text);
-        self.push_layout(&layout,
-                         style,
-                         &transform,
-                         render_mode,
-                         hinting_options,
-                         clip_path,
-                         blend_mode,
-                         paint_id)
+        self.push_layout(scene, &layout, style, render_options)
+    }
+}
+
+impl<F> FontInfo<F> where F: Loader {
+    fn new(font: F) -> FontInfo<F> {
+        FontInfo { font, outline_cache: HashMap::new() }
     }
 }