ConstantSourceNode.offset

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只读 offset 特性为 ConstantSourceNode interface returns a AudioParam object indicating the numeric a-rate value which is always returned by the source when asked for the next sample.

While the AudioParam 命名 offset is read-only, the value property within is not. So you can change the value of offset by setting the value of ConstantSourceNode.offset.value :

myConstantSourceNode.offset.value = newValue;

句法

let offsetParameter = ConstantAudioNode.offset;
let offset = ConstantSourceNode.offset.value;
ConstantSourceNode.offset.value = newValue;

值

AudioParam object indicating the a-rate value returned for every sample by this node. The default value is 1.0.

To access the offset parameter's current value, access the parameter's value property, as shown in the syntax box above.

范例

This example shows how to set up a ConstantSourceNode so its offset is used as the input to a pair of GainNode s; this snippet is derived from the complete example you can find in Controlling multiple parameters with ConstantSourcenode .

gainNode2 = context.createGain();
gainNode3 = context.createGain();
gainNode2.gain.value = gainNode3.gain.value = 0.5;
volumeSliderControl.value = gainNode2.gain.value;
constantSource = context.createConstantSource();
constantSource.connect(gainNode2.gain);
constantSource.connect(gainNode3.gain);

First, the gain nodes are created and configured, and a slider control's value is set to match the gain on the two nodes. Then we create a new ConstantSourceNode and make it the source for the two gain nodes' GainNode.gain values. Each of those values is also an AudioParam .

Let's say we have an event handler (for click events, in this case) which needs to respond by altering the value of the two gain nodes. With the linkage above in place, that can be done using this simple event handler:

function handleClickEvent(event) {
  volumeSliderControl.value = constantSource.offset.value;
}

All this function has to do is fetch the current value of the slider control we're using to control the paired nodes' gains, then store that value into the ConstantSourceNode 's offset parameter. That's done by simply changing the contents of its AudioParam.value property. The two gain nodes quickly adopt the new volume level.

规范

规范	状态	注释
Web 音频 API The definition of 'offset' in that specification.	工作草案

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`offset`	Chrome 56	Edge 79	Firefox 不支持 52 — 53 注意事项 52 — 53 注意事项 This property is still available, but via the inheritance of `AudioScheduledSourceNode` .	IE 不支持 No	Opera 不支持 No	Safari 不支持 No	WebView Android 不支持 No	Chrome Android 不支持 No	Firefox Android 不支持 52 — 53 注意事项 52 — 53 注意事项 This property is still available, but via the inheritance of `AudioScheduledSourceNode` .	Opera Android 不支持 No	Safari iOS 不支持 No	Samsung Internet Android 不支持 No

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