Auto merge of #389 - pcwalton:gradient-wrap, r=pcwalton

Implement gradient wrap/spread modes in SVG.

Closes #386.

content/src/gradient.rs

@@ -24,6 +24,7 @@ use std::mem;
 pub struct Gradient {
     pub geometry: GradientGeometry,
     stops: Vec<ColorStop>,
+    pub wrap: GradientWrap,
 }
 
 #[derive(Clone, Copy, PartialEq, Debug)]
@@ -49,6 +50,12 @@ pub enum GradientGeometry {
     }
 }
 
+#[derive(Clone, Copy, PartialEq, Debug)]
+pub enum GradientWrap {
+    Clamp,
+    Repeat,
+}
+
 impl Eq for Gradient {}
 
 impl Hash for Gradient {
@@ -90,7 +97,11 @@ impl Hash for ColorStop {
 impl Gradient {
     #[inline]
     pub fn linear(line: LineSegment2F) -> Gradient {
-        Gradient { geometry: GradientGeometry::Linear(line), stops: Vec::new() }
+        Gradient {
+            geometry: GradientGeometry::Linear(line),
+            stops: Vec::new(),
+            wrap: GradientWrap::Clamp,
+        }
     }
 
     #[inline]
@@ -104,6 +115,7 @@ impl Gradient {
         Gradient {
             geometry: GradientGeometry::Radial { line: line.to_line(), radii, transform },
             stops: Vec::new(),
+            wrap: GradientWrap::Clamp,
         }
     }
 

renderer/src/paint.rs

@@ -9,13 +9,13 @@
 // except according to those terms.
 
 use crate::allocator::{AllocationMode, TextureAllocator};
-use crate::gpu_data::{ColorCombineMode, RenderCommand, TextureLocation, TextureMetadataEntry, TexturePageDescriptor};
+use crate::gpu_data::{ColorCombineMode, RenderCommand, TextureLocation, TextureMetadataEntry};
-use crate::gpu_data::{TexturePageId, TileBatchTexture};
+use crate::gpu_data::{TexturePageDescriptor, TexturePageId, TileBatchTexture};
 use crate::scene::{RenderTarget, SceneId};
 use hashbrown::HashMap;
 use pathfinder_color::ColorU;
 use pathfinder_content::effects::{BlendMode, Filter, PatternFilter};
-use pathfinder_content::gradient::{Gradient, GradientGeometry};
+use pathfinder_content::gradient::{Gradient, GradientGeometry, GradientWrap};
 use pathfinder_content::pattern::{Pattern, PatternSource};
 use pathfinder_content::render_target::RenderTargetId;
 use pathfinder_geometry::line_segment::LineSegment2F;
@@ -368,12 +368,20 @@ impl Palette {
             let color_texture_metadata = paint.overlay.as_ref().map(|overlay| {
                 match overlay.contents {
                     PaintContents::Gradient(ref gradient) => {
+                        let mut sampling_flags = TextureSamplingFlags::empty();
+                        match gradient.wrap {
+                            GradientWrap::Repeat => {
+                                sampling_flags.insert(TextureSamplingFlags::REPEAT_U);
+                            }
+                            GradientWrap::Clamp => {}
+                        }
+
                         // FIXME(pcwalton): The gradient size might not be big enough. Detect this.
                         let location = gradient_tile_builder.allocate(allocator, gradient);
                         PaintColorTextureMetadata {
                             location,
                             page_scale: allocator.page_scale(location.page),
-                            sampling_flags: TextureSamplingFlags::empty(),
+                            sampling_flags,
                             filter: match gradient.geometry {
                                 GradientGeometry::Linear(_) => PaintFilter::None,
                                 GradientGeometry::Radial { line, radii, .. } => {

svg/src/lib.rs

@@ -17,7 +17,7 @@ use hashbrown::HashMap;
 use pathfinder_color::ColorU;
 use pathfinder_content::dash::OutlineDash;
 use pathfinder_content::fill::FillRule;
-use pathfinder_content::gradient::{ColorStop, Gradient};
+use pathfinder_content::gradient::{ColorStop, Gradient, GradientWrap};
 use pathfinder_content::outline::Outline;
 use pathfinder_content::segment::{Segment, SegmentFlags};
 use pathfinder_content::stroke::{LineCap, LineJoin, OutlineStrokeToFill, StrokeStyle};
@@ -56,7 +56,6 @@ bitflags! {
         const UNSUPPORTED_LINK_PAINT             = 0x0020;
         const UNSUPPORTED_FILTER_ATTR            = 0x0040;
         const UNSUPPORTED_MASK_ATTR              = 0x0080;
-        const UNSUPPORTED_GRADIENT_SPREAD_METHOD = 0x0100;
     }
 }
 
@@ -237,11 +236,27 @@ impl SVGScene {
                     id: String,
                     usvg_base_gradient: &BaseGradient) {
         for stop in &usvg_base_gradient.stops {
-            gradient.add(ColorStop::from_usvg_stop(stop));
+            let mut stop = ColorStop::from_usvg_stop(stop);
+            if usvg_base_gradient.spread_method == SpreadMethod::Reflect {
+                stop.offset *= 0.5;
+            }
+            gradient.add(stop);
         }
 
-        if usvg_base_gradient.spread_method != SpreadMethod::Pad {
+        // Reflect gradient if necessary.
-            self.result_flags.insert(BuildResultFlags::UNSUPPORTED_GRADIENT_SPREAD_METHOD);
+        if usvg_base_gradient.spread_method == SpreadMethod::Reflect {
+            for stop in &usvg_base_gradient.stops {
+                let mut stop = ColorStop::from_usvg_stop(stop);
+                if usvg_base_gradient.spread_method == SpreadMethod::Reflect {
+                    stop.offset = 1.0 - stop.offset * 0.5;
+                }
+                gradient.add(stop);
+            }
+        }
+
+        match usvg_base_gradient.spread_method {
+            SpreadMethod::Pad => {}
+            SpreadMethod::Reflect | SpreadMethod::Repeat => gradient.wrap = GradientWrap::Repeat,
         }
 
         let transform = usvg_transform_to_transform_2d(&usvg_base_gradient.transform);
@@ -304,7 +319,6 @@ impl Display for BuildResultFlags {
             "non-color paint",
             "filter attribute",
             "mask attribute",
-            "gradient spread method",
         ];
     }
 }