servo: Merge #2920 - Implement very basic canvas rendering context logic. No visual display present (from Ms2ger:canvas)

Source-Repo: https://github.com/servo/servo
Source-Revision: 440b2a995ffe76aaff8e8080188e5614b830ae38

servo/src/components/script/dom/canvasrenderingcontext2d.rs

@@ -0,0 +1,147 @@
+/* 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 http://mozilla.org/MPL/2.0/. */
+
+use dom::bindings::codegen::Bindings::CanvasRenderingContext2DBinding;
+use dom::bindings::global::{GlobalRef, GlobalField};
+use dom::bindings::js::{JSRef, Temporary};
+use dom::bindings::trace::Untraceable;
+use dom::bindings::utils::{Reflector, Reflectable, reflect_dom_object};
+
+use azure::azure_hl::{DrawTarget, Color, B8G8R8A8, SkiaBackend, StrokeOptions, DrawOptions};
+use azure::azure_hl::ColorPattern;
+use geom::point::Point2D;
+use geom::rect::Rect;
+use geom::size::Size2D;
+
+use std::comm;
+use std::task::TaskBuilder;
+
+#[deriving(Encodable)]
+pub struct CanvasRenderingContext2D {
+    reflector_: Reflector,
+    global: GlobalField,
+    renderer: Untraceable<Sender<CanvasMsg>>,
+}
+
+enum CanvasMsg {
+    FillRect(Rect<f32>),
+    ClearRect(Rect<f32>),
+    StrokeRect(Rect<f32>),
+    Recreate(Size2D<i32>),
+    Close,
+}
+
+struct CanvasRenderTask {
+    drawtarget: DrawTarget,
+    fill_color: ColorPattern,
+    stroke_color: ColorPattern,
+    stroke_opts: StrokeOptions,
+}
+
+impl CanvasRenderTask {
+    fn new(size: Size2D<i32>) -> CanvasRenderTask {
+        CanvasRenderTask {
+            drawtarget: CanvasRenderTask::create(size),
+            fill_color: ColorPattern::new(Color::new(0., 0., 0., 1.)),
+            stroke_color: ColorPattern::new(Color::new(0., 0., 0., 1.)),
+            stroke_opts: StrokeOptions::new(1.0, 1.0),
+        }
+    }
+
+    fn start(size: Size2D<i32>) -> Sender<CanvasMsg> {
+        let (chan, port) = comm::channel::<CanvasMsg>();
+        let builder = TaskBuilder::new().named("CanvasTask");
+        builder.spawn(proc() {
+            let mut renderer = CanvasRenderTask::new(size);
+
+            loop {
+                match port.recv() {
+                    FillRect(ref rect) => renderer.fill_rect(rect),
+                    StrokeRect(ref rect) => renderer.stroke_rect(rect),
+                    ClearRect(ref rect) => renderer.clear_rect(rect),
+                    Recreate(size) => renderer.recreate(size),
+                    Close => break,
+                }
+            }
+        });
+        chan
+    }
+
+    fn fill_rect(&self, rect: &Rect<f32>) {
+        let drawopts = DrawOptions::new(1.0, 0);
+        self.drawtarget.fill_rect(rect, &self.fill_color, Some(&drawopts));
+    }
+
+    fn clear_rect(&self, rect: &Rect<f32>) {
+        self.drawtarget.clear_rect(rect);
+    }
+
+    fn stroke_rect(&self, rect: &Rect<f32>) {
+        let drawopts = DrawOptions::new(1.0, 0);
+        self.drawtarget.stroke_rect(rect, &self.stroke_color, &self.stroke_opts, &drawopts);
+    }
+
+    fn create(size: Size2D<i32>) -> DrawTarget {
+        DrawTarget::new(SkiaBackend, size, B8G8R8A8)
+    }
+
+    fn recreate(&mut self, size: Size2D<i32>) {
+        self.drawtarget = CanvasRenderTask::create(size);
+    }
+}
+
+impl CanvasRenderingContext2D {
+    pub fn new_inherited(global: &GlobalRef, size: Size2D<i32>) -> CanvasRenderingContext2D {
+        CanvasRenderingContext2D {
+            reflector_: Reflector::new(),
+            global: GlobalField::from_rooted(global),
+            renderer: Untraceable::new(CanvasRenderTask::start(size)),
+        }
+    }
+
+    pub fn new(global: &GlobalRef, size: Size2D<i32>) -> Temporary<CanvasRenderingContext2D> {
+        reflect_dom_object(box CanvasRenderingContext2D::new_inherited(global, size),
+                           global, CanvasRenderingContext2DBinding::Wrap)
+    }
+
+    pub fn recreate(&self, size: Size2D<i32>) {
+        self.renderer.send(Recreate(size));
+    }
+}
+
+pub trait CanvasRenderingContext2DMethods {
+    fn FillRect(&self, x: f64, y: f64, width: f64, height: f64);
+    fn ClearRect(&self, x: f64, y: f64, width: f64, height: f64);
+    fn StrokeRect(&self, x: f64, y: f64, width: f64, height: f64);
+}
+
+impl<'a> CanvasRenderingContext2DMethods for JSRef<'a, CanvasRenderingContext2D> {
+    fn FillRect(&self, x: f64, y: f64, width: f64, height: f64) {
+        let rect = Rect(Point2D(x as f32, y as f32), Size2D(width as f32, height as f32));
+        self.renderer.send(FillRect(rect));
+    }
+
+    fn ClearRect(&self, x: f64, y: f64, width: f64, height: f64) {
+        let rect = Rect(Point2D(x as f32, y as f32), Size2D(width as f32, height as f32));
+        self.renderer.send(ClearRect(rect));
+    }
+
+    fn StrokeRect(&self, x: f64, y: f64, width: f64, height: f64) {
+        let rect = Rect(Point2D(x as f32, y as f32), Size2D(width as f32, height as f32));
+        self.renderer.send(StrokeRect(rect));
+    }
+}
+
+impl Reflectable for CanvasRenderingContext2D {
+    fn reflector<'a>(&'a self) -> &'a Reflector {
+        &self.reflector_
+    }
+}
+
+#[unsafe_destructor]
+impl Drop for CanvasRenderingContext2D {
+    fn drop(&mut self) {
+        self.renderer.send(Close);
+    }
+}

servo/src/components/script/dom/htmlcanvaselement.rs

@@ -4,18 +4,35 @@
 
 use dom::bindings::codegen::Bindings::HTMLCanvasElementBinding;
 use dom::bindings::codegen::InheritTypes::HTMLCanvasElementDerived;
-use dom::bindings::js::{JSRef, Temporary};
+use dom::bindings::codegen::InheritTypes::{ElementCast, HTMLElementCast};
+use dom::bindings::global::Window;
+use dom::bindings::js::{JS, JSRef, Temporary, OptionalSettable};
+use dom::bindings::trace::Traceable;
 use dom::bindings::utils::{Reflectable, Reflector};
+use dom::canvasrenderingcontext2d::CanvasRenderingContext2D;
 use dom::document::Document;
-use dom::element::HTMLCanvasElementTypeId;
+use dom::element::{Element, HTMLCanvasElementTypeId, AttributeHandlers};
 use dom::eventtarget::{EventTarget, NodeTargetTypeId};
 use dom::htmlelement::HTMLElement;
-use dom::node::{Node, ElementNodeTypeId};
+use dom::node::{Node, ElementNodeTypeId, window_from_node};
+use dom::virtualmethods::VirtualMethods;
+
 use servo_util::str::DOMString;
 
+use geom::size::Size2D;
+
+use std::cell::Cell;
+use std::num;
+
+static DefaultWidth: u32 = 300;
+static DefaultHeight: u32 = 150;
+
 #[deriving(Encodable)]
 pub struct HTMLCanvasElement {
     pub htmlelement: HTMLElement,
+    context: Traceable<Cell<Option<JS<CanvasRenderingContext2D>>>>,
+    width: Traceable<Cell<u32>>,
+    height: Traceable<Cell<u32>>,
 }
 
 impl HTMLCanvasElementDerived for EventTarget {
@@ -27,7 +44,10 @@ impl HTMLCanvasElementDerived for EventTarget {
 impl HTMLCanvasElement {
     pub fn new_inherited(localName: DOMString, document: &JSRef<Document>) -> HTMLCanvasElement {
         HTMLCanvasElement {
-            htmlelement: HTMLElement::new_inherited(HTMLCanvasElementTypeId, localName, document)
+            htmlelement: HTMLElement::new_inherited(HTMLCanvasElementTypeId, localName, document),
+            context: Traceable::new(Cell::new(None)),
+            width: Traceable::new(Cell::new(DefaultWidth)),
+            height: Traceable::new(Cell::new(DefaultHeight)),
         }
     }
 
@@ -38,6 +58,106 @@ impl HTMLCanvasElement {
 }
 
 pub trait HTMLCanvasElementMethods {
+    fn Width(&self) -> u32;
+    fn SetWidth(&self, width: u32);
+    fn Height(&self) -> u32;
+    fn SetHeight(&self, height: u32);
+    fn GetContext(&self, id: DOMString) -> Option<Temporary<CanvasRenderingContext2D>>;
+}
+
+impl<'a> HTMLCanvasElementMethods for JSRef<'a, HTMLCanvasElement> {
+    fn Width(&self) -> u32 {
+        self.width.get()
+    }
+
+    fn SetWidth(&self, width: u32) {
+        let elem: &JSRef<Element> = ElementCast::from_ref(self);
+        elem.set_uint_attribute("width", width)
+    }
+
+    fn Height(&self) -> u32 {
+        self.height.get()
+    }
+
+    fn SetHeight(&self, height: u32) {
+        let elem: &JSRef<Element> = ElementCast::from_ref(self);
+        elem.set_uint_attribute("height", height)
+    }
+
+    fn GetContext(&self, id: DOMString) -> Option<Temporary<CanvasRenderingContext2D>> {
+        if id.as_slice() != "2d" {
+            return None;
+        }
+
+        if self.context.get().is_none() {
+            let window = window_from_node(self).root();
+            let (w, h) = (self.width.get() as i32, self.height.get() as i32);
+            let context = CanvasRenderingContext2D::new(&Window(*window), Size2D(w, h));
+            self.context.assign(Some(context));
+        }
+        self.context.get().map(|context| Temporary::new(context))
+     }
+}
+
+impl<'a> VirtualMethods for JSRef<'a, HTMLCanvasElement> {
+    fn super_type<'a>(&'a self) -> Option<&'a VirtualMethods+> {
+        let element: &JSRef<HTMLElement> = HTMLElementCast::from_ref(self);
+        Some(element as &VirtualMethods+)
+    }
+
+    fn before_remove_attr(&self, name: DOMString, value: DOMString) {
+        match self.super_type() {
+            Some(ref s) => s.before_remove_attr(name.clone(), value.clone()),
+            _ => (),
+        }
+
+        let recreate = match name.as_slice() {
+            "width" => {
+                self.width.set(DefaultWidth);
+                true
+            }
+            "height" => {
+                self.height.set(DefaultHeight);
+                true
+            }
+            _ => false,
+        };
+
+        if recreate {
+            let (w, h) = (self.width.get() as i32, self.height.get() as i32);
+            match self.context.get() {
+                Some(ref context) => context.root().recreate(Size2D(w, h)),
+                None => ()
+            }
+        }
+    }
+
+    fn after_set_attr(&self, name: DOMString, value: DOMString) {
+        match self.super_type() {
+            Some(ref s) => s.after_set_attr(name.clone(), value.clone()),
+            _ => (),
+        }
+
+        let recreate = match name.as_slice() {
+            "width" => {
+                self.width.set(num::from_str_radix(value.as_slice(), 10).unwrap());
+                true
+            }
+            "height" => {
+                self.height.set(num::from_str_radix(value.as_slice(), 10).unwrap());
+                true
+            }
+            _ => false,
+        };
+
+        if recreate {
+            let (w, h) = (self.width.get() as i32, self.height.get() as i32);
+            match self.context.get() {
+                Some(ref context) => context.root().recreate(Size2D(w, h)),
+                None => ()
+            }
+        }
+    }
 }
 
 impl Reflectable for HTMLCanvasElement {

servo/src/components/script/dom/virtualmethods.rs

@@ -6,6 +6,7 @@ use dom::attr::{AttrValue, StringAttrValue};
 use dom::bindings::codegen::InheritTypes::ElementCast;
 use dom::bindings::codegen::InheritTypes::HTMLAnchorElementCast;
 use dom::bindings::codegen::InheritTypes::HTMLBodyElementCast;
+use dom::bindings::codegen::InheritTypes::HTMLCanvasElementCast;
 use dom::bindings::codegen::InheritTypes::HTMLElementCast;
 use dom::bindings::codegen::InheritTypes::HTMLIFrameElementCast;
 use dom::bindings::codegen::InheritTypes::HTMLImageElementCast;
@@ -13,11 +14,14 @@ use dom::bindings::codegen::InheritTypes::HTMLObjectElementCast;
 use dom::bindings::codegen::InheritTypes::HTMLStyleElementCast;
 use dom::bindings::js::JSRef;
 use dom::element::Element;
-use dom::element::{ElementTypeId, HTMLAnchorElementTypeId, HTMLBodyElementTypeId, HTMLImageElementTypeId};
-use dom::element::{HTMLIFrameElementTypeId, HTMLObjectElementTypeId, HTMLStyleElementTypeId};
+use dom::element::{ElementTypeId, HTMLAnchorElementTypeId};
+use dom::element::{HTMLBodyElementTypeId, HTMLCanvasElementTypeId};
+use dom::element::{HTMLIFrameElementTypeId, HTMLImageElementTypeId};
+use dom::element::{HTMLObjectElementTypeId, HTMLStyleElementTypeId};
 use dom::event::Event;
 use dom::htmlanchorelement::HTMLAnchorElement;
 use dom::htmlbodyelement::HTMLBodyElement;
+use dom::htmlcanvaselement::HTMLCanvasElement;
 use dom::htmlelement::HTMLElement;
 use dom::htmliframeelement::HTMLIFrameElement;
 use dom::htmlimageelement::HTMLImageElement;
@@ -111,6 +115,10 @@ pub fn vtable_for<'a>(node: &'a JSRef<Node>) -> &'a VirtualMethods+ {
             let element: &JSRef<HTMLBodyElement> = HTMLBodyElementCast::to_ref(node).unwrap();
             element as &VirtualMethods+
         }
+        ElementNodeTypeId(HTMLCanvasElementTypeId) => {
+            let element: &JSRef<HTMLCanvasElement> = HTMLCanvasElementCast::to_ref(node).unwrap();
+            element as &VirtualMethods+
+        }
         ElementNodeTypeId(HTMLImageElementTypeId) => {
             let element: &JSRef<HTMLImageElement> = HTMLImageElementCast::to_ref(node).unwrap();
             element as &VirtualMethods+

servo/src/components/script/dom/webidls/CanvasRenderingContext2D.webidl

@@ -0,0 +1,104 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 http://mozilla.org/MPL/2.0/. */
+
+// http://www.whatwg.org/html/#2dcontext
+//[Constructor(optional unsigned long width, unsigned long height), Exposed=Window,Worker]
+interface CanvasRenderingContext2D {
+
+  // back-reference to the canvas
+  //readonly attribute HTMLCanvasElement canvas;
+
+  // canvas dimensions
+  //         attribute unsigned long width;
+  //         attribute unsigned long height;
+
+  // for contexts that aren't directly fixed to a specific canvas
+  //void commit(); // push the image to the output bitmap
+
+  // state
+  //void save(); // push state on state stack
+  //void restore(); // pop state stack and restore state
+
+  // transformations (default transform is the identity matrix)
+  //         attribute SVGMatrix currentTransform;
+  //void scale(unrestricted double x, unrestricted double y);
+  //void rotate(unrestricted double angle);
+  //void translate(unrestricted double x, unrestricted double y);
+  //void transform(unrestricted double a, unrestricted double b, unrestricted double c, unrestricted double d, unrestricted double e, unrestricted double f);
+  //void setTransform(unrestricted double a, unrestricted double b, unrestricted double c, unrestricted double d, unrestricted double e, unrestricted double f);
+  //void resetTransform();
+
+  // compositing
+  //         attribute unrestricted double globalAlpha; // (default 1.0)
+  //         attribute DOMString globalCompositeOperation; // (default source-over)
+
+  // image smoothing
+  //         attribute boolean imageSmoothingEnabled; // (default true)
+
+  // colours and styles (see also the CanvasDrawingStyles interface)
+  //         attribute (DOMString or CanvasGradient or CanvasPattern) strokeStyle; // (default black)
+  //         attribute (DOMString or CanvasGradient or CanvasPattern) fillStyle; // (default black)
+  //CanvasGradient createLinearGradient(double x0, double y0, double x1, double y1);
+  //CanvasGradient createRadialGradient(double x0, double y0, double r0, double x1, double y1, double r1);
+  //CanvasPattern createPattern(CanvasImageSource image, [TreatNullAs=EmptyString] DOMString repetition);
+
+  // shadows
+  //         attribute unrestricted double shadowOffsetX; // (default 0)
+  //         attribute unrestricted double shadowOffsetY; // (default 0)
+  //         attribute unrestricted double shadowBlur; // (default 0)
+  //         attribute DOMString shadowColor; // (default transparent black)
+
+  // rects
+  //void clearRect(unrestricted double x, unrestricted double y, unrestricted double w, unrestricted double h);
+  //[LenientFloat]
+  void clearRect(double x, double y, double w, double h);
+  //void fillRect(unrestricted double x, unrestricted double y, unrestricted double w, unrestricted double h);
+  //[LenientFloat]
+  void fillRect(double x, double y, double w, double h);
+  //void strokeRect(unrestricted double x, unrestricted double y, unrestricted double w, unrestricted double h);
+  //[LenientFloat]
+  void strokeRect(double x, double y, double w, double h);
+
+  // path API (see also CanvasPathMethods)
+  //void beginPath();
+  //void fill(optional CanvasFillRule fillRule = "nonzero");
+  //void fill(Path2D path, optional CanvasFillRule fillRule = "nonzero");
+  //void stroke();
+  //void stroke(Path2D path);
+  //void drawSystemFocusRing(Element element);
+  //void drawSystemFocusRing(Path2D path, Element element);
+  //boolean drawCustomFocusRing(Element element);
+  //boolean drawCustomFocusRing(Path2D path, Element element);
+  //void scrollPathIntoView();
+  //void scrollPathIntoView(Path2D path);
+  //void clip(optional CanvasFillRule fillRule = "nonzero");
+  //void clip(Path2D path, optional CanvasFillRule fillRule = "nonzero");
+  //void resetClip();
+  //boolean isPointInPath(unrestricted double x, unrestricted double y, optional CanvasFillRule fillRule = "nonzero");
+  //boolean isPointInPath(Path2D path, unrestricted double x, unrestricted double y, optional CanvasFillRule fillRule = "nonzero");
+  //boolean isPointInStroke(unrestricted double x, unrestricted double y);
+  //boolean isPointInStroke(Path2D path, unrestricted double x, unrestricted double y);
+
+  // text (see also the CanvasDrawingStyles interface)
+  //void fillText(DOMString text, unrestricted double x, unrestricted double y, optional unrestricted double maxWidth);
+  //void strokeText(DOMString text, unrestricted double x, unrestricted double y, optional unrestricted double maxWidth);
+  //TextMetrics measureText(DOMString text);
+
+  // drawing images
+  //void drawImage(CanvasImageSource image, unrestricted double dx, unrestricted double dy);
+  //void drawImage(CanvasImageSource image, unrestricted double dx, unrestricted double dy, unrestricted double dw, unrestricted double dh);
+  //void drawImage(CanvasImageSource image, unrestricted double sx, unrestricted double sy, unrestricted double sw, unrestricted double sh, unrestricted double dx, unrestricted double dy, unrestricted double dw, unrestricted double dh);
+
+  // hit regions
+  //void addHitRegion(optional HitRegionOptions options);
+  //void removeHitRegion(DOMString id);
+
+  // pixel manipulation
+  //ImageData createImageData(double sw, double sh);
+  //ImageData createImageData(ImageData imagedata);
+  //ImageData getImageData(double sx, double sy, double sw, double sh);
+  //void putImageData(ImageData imagedata, double dx, double dy);
+  //void putImageData(ImageData imagedata, double dx, double dy, double dirtyX, double dirtyY, double dirtyWidth, double dirtyHeight);
+};

servo/src/components/script/dom/webidls/HTMLCanvasElement.webidl

@@ -7,10 +7,13 @@
 //typedef (CanvasRenderingContext2D or WebGLRenderingContext) RenderingContext;
 
 interface HTMLCanvasElement : HTMLElement {
-  //         attribute unsigned long width;
-  //         attribute unsigned long height;
+  [Pure]
+           attribute unsigned long width;
+  [Pure]
+           attribute unsigned long height;
 
   //RenderingContext? getContext(DOMString contextId, any... arguments);
+  CanvasRenderingContext2D? getContext(DOMString contextId);
   //boolean probablySupportsContext(DOMString contextId, any... arguments);
 
   //void setContext(RenderingContext context);

servo/src/components/script/script.rs

@@ -19,6 +19,7 @@
 #[phase(plugin, link)]
 extern crate log;
 
+extern crate azure;
 extern crate debug;
 extern crate cssparser;
 extern crate collections;
@@ -72,6 +73,7 @@ pub mod dom {
     pub mod attrlist;
     pub mod blob;
     pub mod browsercontext;
+    pub mod canvasrenderingcontext2d;
     pub mod characterdata;
     pub mod clientrect;
     pub mod clientrectlist;

servo/src/test/content/test_interfaces.html

@@ -53,6 +53,7 @@ var ecmaGlobals = [
 var interfaceNamesInGlobalScope = [
   "Attr",
   "Blob",
+  "CanvasRenderingContext2D",
   "CharacterData",
   "ClientRect", // #2814
   "ClientRectList", // #2814

servo/src/test/html/test_canvas.html

@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+<body>
+<canvas id="tutorial" style="border:1px solid #d3d3d3"></canvas>
+<script type="text/javascript">
+
+canvas = document.getElementById('tutorial');
+canvas.width = 200;
+canvas.height = 200;
+
+var ctx = canvas.getContext('2d');
+ctx.fillRect(10.0,10.0,100.0,100.0);
+ctx.strokeRect(20.0,40.0,80.0,80.0);
+ctx.clearRect(10.0,10.0,100.0,100.0);
+
+</script>
+</body>
+</html>