glifo/
interface.rs

1// Copyright 2026 the Vello Authors
2// SPDX-License-Identifier: Apache-2.0 OR MIT
3
4//! Traits for rendering glyphs and replaying them.
5
6use crate::atlas::{AtlasPaint, AtlasSlot};
7use crate::color::{AlphaColor, Srgb};
8use crate::kurbo::{Affine, BezPath, Rect};
9use crate::peniko::BlendMode;
10use vello_common::paint::{Image, ImageSource, PaintType, Tint};
11
12// TODO: This trait is only temporary and will hopefully be replaced once we have a better
13// unifying imaging API.
14/// A sink for low-level glyph drawing commands.
15pub trait DrawSink {
16    /// Set the current transform.
17    fn set_transform(&mut self, t: Affine);
18    /// Set the current paint.
19    fn set_paint(&mut self, paint: AtlasPaint);
20    /// Set the paint transform.
21    fn set_paint_transform(&mut self, t: Affine);
22    /// Fill a path with the current paint and transform.
23    fn fill_path(&mut self, path: &BezPath);
24    /// Fill a rectangle with the current paint and transform.
25    fn fill_rect(&mut self, rect: &Rect);
26    // TODO: `push/pop_clip_layer` are only needed temporarily for Vello renderers so the impact of
27    // destructive blend modes can be limited to a smaller area. Once the limitation is lifted,
28    // we can remove this method and just use `push_clip_path` and `push_blend_layer`.
29    /// Push a clip layer defined by a path.
30    fn push_clip_layer(&mut self, clip: &BezPath);
31    /// Push a clip path.
32    ///
33    /// This method _can_ be implemented in terms of `push_clip_layer` without losing correctness.
34    /// However, clients are allowed to choose a more efficient clipping implementation that
35    /// doesn't require pushing an isolated layer.
36    ///
37    /// When providing a custom implementation of this method, the `pop_clip_path` method also
38    /// needs to be overridden correspondingly.
39    fn push_clip_path(&mut self, clip: &BezPath) {
40        self.push_clip_layer(clip);
41    }
42    /// Push a blend/compositing layer.
43    fn push_blend_layer(&mut self, blend_mode: BlendMode);
44    /// Pop the most recent clip or blend layer.
45    fn pop_layer(&mut self);
46    /// Pop the most recent clip path.
47    ///
48    /// See the documentation for [`DrawSink::push_clip_path`].
49    fn pop_clip_path(&mut self) {
50        self.pop_layer();
51    }
52    /// Width of the surface.
53    fn width(&self) -> u16;
54    /// Height of the surface.
55    fn height(&self) -> u16;
56}
57
58/// A stateful renderer that can draw sequences of cached and uncached glyphs.
59pub trait GlyphRenderer: DrawSink {
60    /// The type of state used by the renderer.
61    type SavedState;
62
63    /// Save the current state.
64    fn save_state(&mut self) -> Self::SavedState;
65
66    /// Restore the current state.
67    fn restore_state(&mut self, state: Self::SavedState);
68
69    /// Stroke a path with the current paint and stroke settings.
70    fn stroke_path(&mut self, path: &BezPath);
71
72    /// Set the current paint to an image.
73    fn set_paint_image(&mut self, image: Image);
74
75    /// Set the tint for subsequent image draws.
76    fn set_tint(&mut self, tint: Option<Tint>);
77
78    /// Get the context color from the renderer's current paint, used for resolving the
79    /// context-dependent colors of COLR glyphs.
80    fn get_context_color(&self) -> AlphaColor<Srgb>;
81
82    /// Get the currently active paint.
83    fn current_paint(&self) -> &PaintType;
84
85    // Hopefully we can get rid of those below in the future.
86
87    /// Construct the [`ImageSource`] for sampling a cached glyph from the atlas.
88    fn atlas_image_source(&self, atlas_slot: &AtlasSlot) -> ImageSource;
89
90    /// Compute the paint transform for sampling a cached glyph from the atlas.
91    fn atlas_paint_transform(&self, atlas_slot: &AtlasSlot) -> Affine;
92}
glifo/interface.rs

glifo/
interface.rs
