Add cargo feature to control canvas backend.

components/canvas/raqote_backend.rs

@@ -0,0 +1,124 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use cssparser::RGBA;
+use crate::canvas_data::{
+    Backend, CanvasPaintState, Color, CompositionOp, DrawOptions, GenericDrawTarget,
+    GenericPathBuilder, Path, Pattern, StrokeOptions,
+};
+use crate::canvas_paint_thread::AntialiasMode;
+use canvas_traits::canvas::*;
+use euclid::{Rect, Size2D, Transform2D};
+use std::marker::PhantomData;
+
+pub struct RaqoteBackend;
+
+impl Backend for RaqoteBackend {
+    fn get_composition_op(&self, _opts: &DrawOptions) -> CompositionOp {
+        unimplemented!()
+    }
+
+    fn need_to_draw_shadow(&self, _color: &Color) -> bool {
+        unimplemented!()
+    }
+
+    fn size_from_pattern(&self, _rect: &Rect<f32>, _pattern: &Pattern) -> Option<Size2D<f32>> {
+        unimplemented!()
+    }
+
+    fn set_shadow_color<'a>(&mut self, _color: RGBA, _state: &mut CanvasPaintState<'a>) {
+        unimplemented!()
+    }
+
+    fn set_fill_style<'a>(
+        &mut self,
+        _style: FillOrStrokeStyle,
+        _state: &mut CanvasPaintState<'a>,
+        _drawtarget: &GenericDrawTarget,
+    ) {
+        unimplemented!()
+    }
+
+    fn set_stroke_style<'a>(
+        &mut self,
+        _style: FillOrStrokeStyle,
+        _state: &mut CanvasPaintState<'a>,
+        _drawtarget: &GenericDrawTarget)
+    {
+        unimplemented!()
+    }
+
+    fn set_global_composition<'a>(&mut self, _op: CompositionOrBlending, _state: &mut CanvasPaintState<'a>) {
+        unimplemented!()
+    }
+
+    fn create_drawtarget(&self, _size: Size2D<u64>) -> Box<GenericDrawTarget> {
+        unimplemented!()
+    }
+
+    fn recreate_paint_state<'a>(&self, _state: &CanvasPaintState<'a>) -> CanvasPaintState<'a> {
+        CanvasPaintState::new(AntialiasMode::Default)
+    }
+}
+
+impl<'a> CanvasPaintState<'a> {
+    pub fn new(_antialias: AntialiasMode) -> CanvasPaintState<'a> {
+        CanvasPaintState {
+            draw_options: DrawOptions::Raqote(()),
+            fill_style: Pattern::Raqote(()),
+            stroke_style: Pattern::Raqote(()),
+            stroke_opts: StrokeOptions::Raqote(PhantomData),
+            transform: Transform2D::identity(),
+            shadow_offset_x: 0.0,
+            shadow_offset_y: 0.0,
+            shadow_blur: 0.0,
+            shadow_color: Color::Raqote(()),
+        }        
+    }
+}
+
+impl Pattern {
+    pub fn is_zero_size_gradient(&self) -> bool {
+        match *self  {
+            Pattern::Raqote(()) => unimplemented!(),
+        }
+    }
+}
+
+impl<'a> StrokeOptions<'a> {
+    pub fn set_line_width(&mut self, _val: f32) {
+        unimplemented!()
+    }
+    pub fn set_miter_limit(&mut self, _val: f32) {
+        unimplemented!()
+    }
+    pub fn set_line_join(&mut self, _val: LineJoinStyle) {
+        unimplemented!()
+    }
+    pub fn set_line_cap(&mut self, _val: LineCapStyle) {
+        unimplemented!()
+    }
+}
+
+impl DrawOptions {
+    pub fn set_alpha(&mut self, _val: f32) {
+        match self {
+            DrawOptions::Raqote(()) => unimplemented!(),
+        }
+    }
+}
+
+impl Path {
+    pub fn transformed_copy_to_builder(&self, _transform: &Transform2D<f32>) -> Box<GenericPathBuilder> {
+        unimplemented!()
+    }
+
+    pub fn contains_point(&self, _x: f64, _y: f64, _path_transform: &Transform2D<f32>) -> bool {
+        unimplemented!()
+    }
+
+    pub fn copy_to_builder(&self) -> Box<GenericPathBuilder> {
+        unimplemented!()
+    }
+}