GainNode

components/script/dom/gainnode.rs

@@ -0,0 +1,97 @@
+/* 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::audionode::AudioNode;
+use dom::audioparam::{AudioParam, AudioParamImpl};
+use dom::baseaudiocontext::BaseAudioContext;
+use dom::bindings::codegen::Bindings::AudioParamBinding::AutomationRate;
+use dom::bindings::codegen::Bindings::AudioNodeBinding::AudioNodeOptions;
+use dom::bindings::codegen::Bindings::AudioNodeBinding::{ChannelCountMode, ChannelInterpretation};
+use dom::bindings::codegen::Bindings::GainNodeBinding::{self, GainNodeMethods, GainOptions};
+use dom::bindings::error::Fallible;
+use dom::bindings::reflector::reflect_dom_object;
+use dom::bindings::root::DomRoot;
+use dom::window::Window;
+use dom_struct::dom_struct;
+use servo_media::audio::context::AudioContext;
+use servo_media::audio::gain_node::{GainNodeMessage, GainNodeOptions};
+use servo_media::audio::graph::NodeId;
+use servo_media::audio::node::{AudioNodeMessage, AudioNodeType};
+use servo_media::audio::param::{UserAutomationEvent, RampKind};
+use std::f32;
+use std::rc::Rc;
+
+audio_param_impl!(Gain, GainNode, GainNodeMessage, SetGain);
+
+#[dom_struct]
+pub struct GainNode {
+    node: AudioNode,
+    gain: DomRoot<AudioParam>,
+}
+
+impl GainNode {
+    #[allow(unsafe_code)]
+    #[allow(unrooted_must_root)]
+    pub fn new_inherited(
+        window: &Window,
+        context: &BaseAudioContext,
+        gain_options: &GainOptions,
+        ) -> GainNode {
+        let mut node_options = unsafe { AudioNodeOptions::empty(window.get_cx()) };
+        node_options.channelCount = Some(2);
+        node_options.channelCountMode = Some(ChannelCountMode::Max);
+        node_options.channelInterpretation = Some(ChannelInterpretation::Speakers);
+        let node = AudioNode::new_inherited(
+            AudioNodeType::GainNode(gain_options.into()),
+            None,
+            context,
+            &node_options,
+            1, // inputs
+            1, // outputs
+            );
+        let gain = Gain::new(context.audio_context_impl(), node.node_id());
+        let gain = AudioParam::new(window,
+                                   Box::new(gain),
+                                   AutomationRate::A_rate,
+                                   1., // default value
+                                   f32::MIN, // min value
+                                   f32::MAX, // max value
+                                  );
+        GainNode {
+            node,
+            gain
+        }
+    }
+
+    #[allow(unrooted_must_root)]
+    pub fn new(window: &Window,
+               context: &BaseAudioContext,
+               options: &GainOptions
+              ) -> DomRoot<GainNode> {
+        let node = GainNode::new_inherited(window, context, options);
+        reflect_dom_object(Box::new(node), window, GainNodeBinding::Wrap)
+    }
+
+    pub fn Constructor(
+        window: &Window,
+        context: &BaseAudioContext,
+        options: &GainOptions,
+        ) -> Fallible<DomRoot<GainNode>> {
+        Ok(GainNode::new(window, context, options))
+    }
+}
+
+impl GainNodeMethods for GainNode {
+    fn Gain(&self) -> DomRoot<AudioParam> {
+        DomRoot::from_ref(&self.gain)
+    }
+}
+
+impl<'a> From<&'a GainOptions> for GainNodeOptions {
+    fn from(options: &'a GainOptions) -> Self {
+        Self {
+            gain: *options.gain,
+        }
+    }
+}

components/script/dom/mod.rs

@@ -296,6 +296,7 @@ pub mod filereader;
 pub mod filereadersync;
 pub mod focusevent;
 pub mod formdata;
+pub mod gainnode;
 pub mod gamepad;
 pub mod gamepadbutton;
 pub mod gamepadbuttonlist;

components/script/dom/webidls/GainNode.webidl

@@ -0,0 +1,17 @@
+/* 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/. */
+/*
+ * The origin of this IDL file is
+ * https://webaudio.github.io/web-audio-api/#gainnode
+ */
+
+dictionary GainOptions : AudioNodeOptions {
+  float gain = 1.0;
+};
+
+[Exposed=Window,
+ Constructor (BaseAudioContext context, optional GainOptions options)]
+ interface GainNode : AudioNode {
+   readonly attribute AudioParam gain;
+ };