dom: Add stub implementation for HTMLCanvasElement.captureStream.

4 files changed, 24 insertions, 0 deletions

diff --git a/components/config/prefs.rs b/components/config/prefs.rs
index bf78d8d584d..a3302e1f597 100644
--- a/components/config/prefs.rs
+++ b/components/config/prefs.rs
@@ -133,6 +133,9 @@ mod gen {
                         enabled: bool,
                     }
                 },
+                canvas_capture: {
+                    enabled: bool,
+                },
                 canvas_text: {
                     enabled: bool,
                 },
diff --git a/components/script/dom/htmlcanvaselement.rs b/components/script/dom/htmlcanvaselement.rs
index 4b7d54b323d..c9060c7d8f3 100644
--- a/components/script/dom/htmlcanvaselement.rs
+++ b/components/script/dom/htmlcanvaselement.rs
@@ -7,10 +7,12 @@ use crate::dom::bindings::cell::{ref_filter_map, DomRefCell, Ref};
 use crate::dom::bindings::codegen::Bindings::HTMLCanvasElementBinding::{
     HTMLCanvasElementMethods, RenderingContext,
 };
+use crate::dom::bindings::codegen::Bindings::MediaStreamBinding::MediaStreamMethods;
 use crate::dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::WebGLContextAttributes;
 use crate::dom::bindings::conversions::ConversionResult;
 use crate::dom::bindings::error::{Error, Fallible};
 use crate::dom::bindings::inheritance::Castable;
+use crate::dom::bindings::num::Finite;
 use crate::dom::bindings::reflector::DomObject;
 use crate::dom::bindings::root::{Dom, DomRoot, LayoutDom};
 use crate::dom::bindings::str::{DOMString, USVString};
@@ -22,6 +24,8 @@ use crate::dom::element::{AttributeMutation, Element, LayoutElementHelpers};
 use crate::dom::globalscope::GlobalScope;
 use crate::dom::gpucanvascontext::GPUCanvasContext;
 use crate::dom::htmlelement::HTMLElement;
+use crate::dom::mediastream::MediaStream;
+use crate::dom::mediastreamtrack::MediaStreamTrack;
 use crate::dom::node::{window_from_node, Node};
 use crate::dom::virtualmethods::VirtualMethods;
 use crate::dom::webgl2renderingcontext::WebGL2RenderingContext;
@@ -41,6 +45,8 @@ use js::rust::HandleValue;
 use profile_traits::ipc;
 use script_layout_interface::{HTMLCanvasData, HTMLCanvasDataSource};
 use script_traits::ScriptMsg;
+use servo_media::streams::registry::MediaStreamId;
+use servo_media::streams::MediaStreamType;
 use style::attr::{AttrValue, LengthOrPercentageOrAuto};
 
 const DEFAULT_WIDTH: u32 = 300;
@@ -429,6 +435,15 @@ impl HTMLCanvasElementMethods for HTMLCanvasElement {
         base64::encode_config_buf(&png, base64::STANDARD, &mut url);
         Ok(USVString(url))
     }
+
+    /// https://w3c.github.io/mediacapture-fromelement/#dom-htmlcanvaselement-capturestream
+    fn CaptureStream(&self, _frame_request_rate: Option<Finite<f64>>) -> DomRoot<MediaStream> {
+        let global = self.global();
+        let stream = MediaStream::new(&*global);
+        let track = MediaStreamTrack::new(&*global, MediaStreamId::new(), MediaStreamType::Video);
+        stream.AddTrack(&track);
+        stream
+    }
 }
 
 impl VirtualMethods for HTMLCanvasElement {
diff --git a/components/script/dom/webidls/HTMLCanvasElement.webidl b/components/script/dom/webidls/HTMLCanvasElement.webidl
index 650357a905e..5c33aa3532e 100644
--- a/components/script/dom/webidls/HTMLCanvasElement.webidl
+++ b/components/script/dom/webidls/HTMLCanvasElement.webidl
@@ -23,4 +23,9 @@ interface HTMLCanvasElement : HTMLElement {
   //OffscreenCanvas transferControlToOffscreen();
 };
 
+partial interface HTMLCanvasElement {
+    [Pref="dom.canvas_capture.enabled"]
+    MediaStream captureStream (optional double frameRequestRate);
+};
+
 //callback BlobCallback = void (Blob? blob);
diff --git a/resources/prefs.json b/resources/prefs.json
index 0b219f7966a..04ecb8f89b7 100644
--- a/resources/prefs.json
+++ b/resources/prefs.json
@@ -1,6 +1,7 @@
 {
   "dom.bluetooth.enabled": false,
   "dom.bluetooth.testing.enabled": false,
+  "dom.canvas_capture.enabled": false,
   "dom.canvas_text.enabled": true,
   "dom.compositionevent.enabled": false,
   "dom.customelements.enabled": true,