Initial Steps OffScreenCanvas API

1 files changed, 146 insertions, 0 deletions

diff --git a/components/script/dom/offscreencanvas.rs b/components/script/dom/offscreencanvas.rs
new file mode 100644
index 00000000000..93c836be5ae
--- /dev/null
+++ b/components/script/dom/offscreencanvas.rs
@@ -0,0 +1,146 @@
+/* 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 crate::dom::bindings::cell::DomRefCell;
+use crate::dom::bindings::codegen::Bindings::OffscreenCanvasBinding::{
+    OffscreenCanvasMethods, OffscreenRenderingContext, Wrap as OffscreenCanvasWrap,
+};
+use crate::dom::bindings::error::Fallible;
+use crate::dom::bindings::reflector::reflect_dom_object;
+use crate::dom::bindings::reflector::DomObject;
+use crate::dom::bindings::root::{Dom, DomRoot};
+use crate::dom::bindings::str::DOMString;
+use crate::dom::eventtarget::EventTarget;
+use crate::dom::globalscope::GlobalScope;
+use crate::dom::htmlcanvaselement::HTMLCanvasElement;
+use crate::dom::offscreencanvasrenderingcontext2d::OffscreenCanvasRenderingContext2D;
+use dom_struct::dom_struct;
+use euclid::Size2D;
+use js::jsapi::JSContext;
+use js::rust::HandleValue;
+use ref_filter_map;
+use std::cell::Cell;
+use std::cell::Ref;
+
+#[must_root]
+#[derive(Clone, JSTraceable, MallocSizeOf)]
+pub enum OffscreenCanvasContext {
+    OffscreenContext2d(Dom<OffscreenCanvasRenderingContext2D>),
+    //WebGL(Dom<WebGLRenderingContext>),
+    //WebGL2(Dom<WebGL2RenderingContext>),
+}
+
+#[dom_struct]
+pub struct OffscreenCanvas {
+    eventtarget: EventTarget,
+    height: Cell<u64>,
+    width: Cell<u64>,
+    context: DomRefCell<Option<OffscreenCanvasContext>>,
+    placeholder: Option<Dom<HTMLCanvasElement>>,
+}
+
+impl OffscreenCanvas {
+    pub fn new_inherited(
+        height: u64,
+        width: u64,
+        placeholder: Option<&HTMLCanvasElement>,
+    ) -> OffscreenCanvas {
+        OffscreenCanvas {
+            eventtarget: EventTarget::new_inherited(),
+            height: Cell::new(height),
+            width: Cell::new(width),
+            context: DomRefCell::new(None),
+            placeholder: placeholder.map(Dom::from_ref),
+        }
+    }
+
+    pub fn new(
+        global: &GlobalScope,
+        height: u64,
+        width: u64,
+        placeholder: Option<&HTMLCanvasElement>,
+    ) -> DomRoot<OffscreenCanvas> {
+        reflect_dom_object(
+            Box::new(OffscreenCanvas::new_inherited(height, width, placeholder)),
+            global,
+            OffscreenCanvasWrap,
+        )
+    }
+
+    pub fn Constructor(
+        global: &GlobalScope,
+        height: u64,
+        width: u64,
+    ) -> Fallible<DomRoot<OffscreenCanvas>> {
+        let offscreencanvas = OffscreenCanvas::new(global, height, width, None);
+        Ok(offscreencanvas)
+    }
+
+    pub fn get_size(&self) -> Size2D<u64> {
+        Size2D::new(self.Width(), self.Height())
+    }
+
+    pub fn context(&self) -> Option<Ref<OffscreenCanvasContext>> {
+        ref_filter_map::ref_filter_map(self.context.borrow(), |ctx| ctx.as_ref())
+    }
+
+    #[allow(unsafe_code)]
+    fn get_or_init_2d_context(&self) -> Option<DomRoot<OffscreenCanvasRenderingContext2D>> {
+        if let Some(ctx) = self.context() {
+            return match *ctx {
+                OffscreenCanvasContext::OffscreenContext2d(ref ctx) => Some(DomRoot::from_ref(ctx)),
+            };
+        }
+        let size = self.get_size();
+        let context = OffscreenCanvasRenderingContext2D::new(&self.global(), self, size);
+        *self.context.borrow_mut() = Some(OffscreenCanvasContext::OffscreenContext2d(
+            Dom::from_ref(&*context),
+        ));
+        Some(context)
+    }
+}
+
+impl OffscreenCanvasMethods for OffscreenCanvas {
+    // https://html.spec.whatwg.org/multipage/#dom-offscreencanvas-getcontext
+    #[allow(unsafe_code)]
+    unsafe fn GetContext(
+        &self,
+        _cx: *mut JSContext,
+        id: DOMString,
+        _options: HandleValue,
+    ) -> Option<OffscreenRenderingContext> {
+        match &*id {
+            "2d" => self
+                .get_or_init_2d_context()
+                .map(OffscreenRenderingContext::OffscreenCanvasRenderingContext2D),
+            /*"webgl" | "experimental-webgl" => self
+                .get_or_init_webgl_context(cx, options)
+                .map(OffscreenRenderingContext::WebGLRenderingContext),
+            "webgl2" | "experimental-webgl2" => self
+                .get_or_init_webgl2_context(cx, options)
+                .map(OffscreenRenderingContext::WebGL2RenderingContext),*/
+            _ => None,
+        }
+    }
+
+    // https://html.spec.whatwg.org/multipage/#dom-offscreencanvas-width
+    fn Width(&self) -> u64 {
+        return self.width.get();
+    }
+
+    // https://html.spec.whatwg.org/multipage/#dom-offscreencanvas-width
+    fn SetWidth(&self, value: u64) {
+        self.width.set(value);
+    }
+
+    // https://html.spec.whatwg.org/multipage/#dom-offscreencanvas-height
+    fn Height(&self) -> u64 {
+        return self.height.get();
+    }
+
+    // https://html.spec.whatwg.org/multipage/#dom-offscreencanvas-height
+    fn SetHeight(&self, value: u64) {
+        self.height.set(value);
+    }
+}