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// Copyright 2006 The Android Open Source Project // Copyright 2020 Evgeniy Reizner // // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. use crate::*; use crate::pipeline::RasterPipelineBlitter; use crate::scalar::Scalar; use crate::scan; use crate::stroker::PathStroker; #[cfg(all(not(feature = "std"), feature = "libm"))] use crate::scalar::FloatExt; // 8K is 1 too big, since 8K << supersample == 32768 which is too big for Fixed. const MAX_DIM: u32 = 8192 - 1; /// A path filling rule. #[derive(Copy, Clone, PartialEq, Debug)] pub enum FillRule { /// Specifies that "inside" is computed by a non-zero sum of signed edge crossings. Winding, /// Specifies that "inside" is computed by an odd number of edge crossings. EvenOdd, } impl Default for FillRule { fn default() -> Self { FillRule::Winding } } /// Controls how a shape should be painted. #[derive(Clone, Debug)] pub struct Paint<'a> { /// A paint shader. /// /// Default: black color pub shader: Shader<'a>, /// Paint blending mode. /// /// Default: SourceOver pub blend_mode: BlendMode, /// Enables anti-aliased painting. /// /// Default: false pub anti_alias: bool, /// Forces the high quality/precision rendering pipeline. /// /// `tiny-skia`, just like Skia, has two rendering pipelines: /// one uses `f32` and another one uses `u16`. `u16` one is usually way faster, /// but less precise. Which can lead to slight differences. /// /// By default, `tiny-skia` will choose the pipeline automatically, /// depending on a blending mode and other parameters. /// But you can force the high quality one using this flag. /// /// This feature is especially useful during testing. /// /// Unlike high quality pipeline, the low quality one doesn't support all /// rendering stages, therefore we cannot force it like hq one. /// /// Default: false pub force_hq_pipeline: bool, } impl Default for Paint<'_> { fn default() -> Self { Paint { shader: Shader::SolidColor(Color::BLACK), blend_mode: BlendMode::default(), anti_alias: false, force_hq_pipeline: false, } } } impl<'a> Paint<'a> { /// Sets a paint source to a solid color. pub fn set_color(&mut self, color: Color) { self.shader = Shader::SolidColor(color); } /// Sets a paint source to a solid color. /// /// `self.shader = Shader::SolidColor(Color::from_rgba8(50, 127, 150, 200));` shorthand. pub fn set_color_rgba8(&mut self, r: u8, g: u8, b: u8, a: u8) { self.set_color(Color::from_rgba8(r, g, b, a)) } /// Checks that the paint source is a solid color. pub fn is_solid_color(&self) -> bool { matches!(self.shader, Shader::SolidColor(_)) } } impl Pixmap { /// Draws a filled rectangle onto the pixmap. /// /// See [`PixmapMut::fill_rect`](struct.PixmapMut.html#method.fill_rect) for details. pub fn fill_rect( &mut self, rect: Rect, paint: &Paint, transform: Transform, clip_mask: Option<&ClipMask>, ) -> Option<()> { self.as_mut().fill_rect(rect, paint, transform, clip_mask) } /// Draws a filled path onto the pixmap. /// /// See [`PixmapMut::fill_path`](struct.PixmapMut.html#method.fill_path) for details. pub fn fill_path( &mut self, path: &Path, paint: &Paint, fill_rule: FillRule, transform: Transform, clip_mask: Option<&ClipMask>, ) -> Option<()> { self.as_mut().fill_path(path, paint, fill_rule, transform, clip_mask) } /// Strokes a path. /// /// See [`PixmapMut::stroke_path`](struct.PixmapMut.html#method.stroke_path) for details. pub fn stroke_path( &mut self, path: &Path, paint: &Paint, stroke: &Stroke, transform: Transform, clip_mask: Option<&ClipMask>, ) -> Option<()> { self.as_mut().stroke_path(path, paint, stroke, transform, clip_mask) } /// Draws a `Pixmap` on top of the current `Pixmap`. /// /// See [`PixmapMut::draw_pixmap`](struct.PixmapMut.html#method.draw_pixmap) for details. pub fn draw_pixmap( &mut self, x: i32, y: i32, pixmap: PixmapRef, paint: &PixmapPaint, transform: Transform, clip_mask: Option<&ClipMask>, ) -> Option<()> { self.as_mut().draw_pixmap(x, y, pixmap, paint, transform, clip_mask) } } impl PixmapMut<'_> { /// Draws a filled rectangle onto the pixmap. /// /// This function is usually slower than filling a rectangular path, /// but it produces better results. Mainly it doesn't suffer from weird /// clipping of horizontal/vertical edges. /// /// Used mainly to render a pixmap onto a pixmap. /// /// Returns `None` when there is nothing to fill or in case of a numeric overflow. pub fn fill_rect( &mut self, rect: Rect, paint: &Paint, transform: Transform, clip_mask: Option<&ClipMask>, ) -> Option<()> { if transform.is_identity() { // TODO: ignore rects outside the pixmap // TODO: draw tiler let bbox = rect.round_out(); if bbox.width() > MAX_DIM || bbox.height() > MAX_DIM { return None; } let clip = self.size().to_screen_int_rect(0, 0); let clip_mask = clip_mask.map(|mask| &mask.mask); let mut blitter = RasterPipelineBlitter::new(paint, clip_mask, self)?; if paint.anti_alias { scan::fill_rect_aa(&rect, &clip, &mut blitter) } else { scan::fill_rect(&rect, &clip, &mut blitter) } } else { let path = PathBuilder::from_rect(rect); self.fill_path(&path, paint, FillRule::Winding, transform, clip_mask) } } /// Draws a filled path onto the pixmap. /// /// Returns `None` when there is nothing to fill or in case of a numeric overflow. pub fn fill_path( &mut self, path: &Path, paint: &Paint, fill_rule: FillRule, transform: Transform, clip_mask: Option<&ClipMask>, ) -> Option<()> { if transform.is_identity() { // This is sort of similar to SkDraw::drawPath // to_rect will fail when bounds' width/height is zero. // This is an intended behaviour since the only // reason for width/height to be zero is a horizontal/vertical line. // And in both cases there is nothing to fill. let path_bounds = path.bounds(); let path_int_bounds = path_bounds.round_out(); // TODO: ignore paths outside the pixmap // TODO: draw tiler if path_int_bounds.width() > MAX_DIM || path_int_bounds.height() > MAX_DIM { return None; } if path.is_too_big_for_math() { return None; } let clip_rect = self.size().to_screen_int_rect(0, 0); let clip_mask = clip_mask.map(|mask| &mask.mask); let mut blitter = RasterPipelineBlitter::new(paint, clip_mask, self)?; if paint.anti_alias { scan::path_aa::fill_path(path, fill_rule, &clip_rect, &mut blitter) } else { scan::path::fill_path(path, fill_rule, &clip_rect, &mut blitter) } } else { let path = path.clone().transform(transform)?; let mut paint = paint.clone(); paint.shader.transform(transform); self.fill_path(&path, &paint, fill_rule, Transform::identity(), clip_mask) } } // TODO: add dash /// Strokes a path. /// /// Stroking is implemented using two separate algorithms: /// /// 1. If a stroke width is wider than 1px (after applying the transformation), /// a path will be converted into a stroked path and then filled using `Canvas::fill_path`. /// Which means that we have to allocate a separate `Path`, that can be 2-3x larger /// then the original path. /// `Canvas` will reuse this allocation during subsequent strokes. /// 2. If a stroke width is thinner than 1px (after applying the transformation), /// we will use hairline stroking, which doesn't involve a separate path allocation. /// /// Also, if a `stroke` has a dash array, then path will be converted into /// a dashed path first and then stroked. Which means a yet another allocation. pub fn stroke_path( &mut self, path: &Path, paint: &Paint, stroke: &Stroke, transform: Transform, clip_mask: Option<&ClipMask>, ) -> Option<()> { if stroke.width < 0.0 { return None; } let res_scale = PathStroker::compute_resolution_scale(&transform); let dash_path; let path = if let Some(ref dash) = stroke.dash { dash_path = crate::dash::dash(path, dash, res_scale)?; &dash_path } else { path }; if let Some(coverage) = treat_as_hairline(&paint, stroke, transform) { let mut paint = paint.clone(); if coverage == 1.0 { // No changes to the `paint`. } else if paint.blend_mode.should_pre_scale_coverage() { // This is the old technique, which we preserve for now so // we don't change previous results (testing) // the new way seems fine, its just (a tiny bit) different. let scale = (coverage * 256.0) as i32; let new_alpha = (255 * scale) >> 8; paint.shader.apply_opacity(new_alpha as f32 / 255.0); } if !transform.is_identity() { paint.shader.transform(transform); let path = path.clone().transform(transform)?; self.stroke_hairline(&path, &paint, stroke.line_cap, clip_mask) } else { self.stroke_hairline(&path, &paint, stroke.line_cap, clip_mask) } } else { let path = PathStroker::new().stroke(path, stroke, res_scale)?; self.fill_path(&path, paint, FillRule::Winding, transform, clip_mask) } } /// A path stroking with subpixel width. /// /// Should be used when stroke width is <= 1.0 /// This function doesn't even accept width, which should be regulated via opacity. /// /// See [`Canvas::stroke_path`] for details. /// /// [`Canvas::stroke_path`]: struct.Canvas.html#method.stroke_path pub(crate) fn stroke_hairline( &mut self, path: &Path, paint: &Paint, line_cap: LineCap, clip_mask: Option<&ClipMask>, ) -> Option<()> { let clip = self.size().to_screen_int_rect(0, 0); let clip_mask = clip_mask.map(|mask| &mask.mask); let mut blitter = RasterPipelineBlitter::new(paint, clip_mask, self)?; if paint.anti_alias { scan::hairline_aa::stroke_path(path, line_cap, &clip, &mut blitter) } else { scan::hairline::stroke_path(path, line_cap, &clip, &mut blitter) } } /// Draws a `Pixmap` on top of the current `Pixmap`. /// /// We basically filling a rectangle with a `pixmap` pattern. pub fn draw_pixmap( &mut self, x: i32, y: i32, pixmap: PixmapRef, paint: &PixmapPaint, transform: Transform, clip_mask: Option<&ClipMask>, ) -> Option<()> { let rect = pixmap.size().to_int_rect(x, y).to_rect(); // TODO: SkSpriteBlitter // TODO: partially clipped // TODO: clipped out // Translate pattern as well as bounds. let patt_transform = Transform::from_translate(x as f32, y as f32); let paint = Paint { shader: Pattern::new( pixmap, SpreadMode::Pad, // Pad, otherwise we will get weird borders overlap. paint.quality, paint.opacity, patt_transform, ), blend_mode: paint.blend_mode, anti_alias: false, // Skia doesn't use it too. force_hq_pipeline: false, // Pattern will use hq anyway. }; self.fill_rect(rect, &paint, transform, clip_mask) } } fn treat_as_hairline(paint: &Paint, stroke: &Stroke, mut ts: Transform) -> Option<f32> { fn fast_len(p: Point) -> f32 { let mut x = p.x.abs(); let mut y = p.y.abs(); if x < y { core::mem::swap(&mut x, &mut y); } x + y.half() } debug_assert!(stroke.width >= 0.0); if stroke.width == 0.0 { return Some(1.0); } if !paint.anti_alias { return None; } // We don't care about translate. ts.tx = 0.0; ts.ty = 0.0; // We need to try to fake a thick-stroke with a modulated hairline. let mut points = [Point::from_xy(stroke.width, 0.0), Point::from_xy(0.0, stroke.width)]; ts.map_points(&mut points); let len0 = fast_len(points[0]); let len1 = fast_len(points[1]); if len0 <= 1.0 && len1 <= 1.0 { return Some(len0.ave(len1)); } None }