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• 句法
• 范例
• 规范
• 浏览器兼容性
• 相关话题

grabFrame() 方法在 ImageCapture interface takes a snapshot of the live video in a MediaStreamTrack 并返回 Promise that resolves with a ImageBitmap containing the snapshot.

句法

const bitmapPromise = imageCapture.grabFrame()
					

返回值

A Promise that resolves to an ImageBitmap 对象。

范例

This example is extracted from this Simple Image Capture demo . It shows how to use the Promise 返回通过 grabFrame() to copy the returned frame to a <canvas> element. For simplicy it does not show how to instantiate the ImageCapture 对象。

var grabFrameButton = document.querySelector('button#grabFrame');
var canvas = document.querySelector('canvas');
grabFrameButton.onclick = grabFrame;
function grabFrame() {
  imageCapture.grabFrame()
  .then(function(imageBitmap) {
    console.log('Grabbed frame:', imageBitmap);
    canvas.width = imageBitmap.width;
    canvas.height = imageBitmap.height;
    canvas.getContext('2d').drawImage(imageBitmap, 0, 0);
    canvas.classList.remove('hidden');
  })
  .catch(function(error) {
    console.log('grabFrame() error: ', error);
  });
}
					

规范

规范	状态	注释
MediaStream 图像捕获 The definition of 'grabFrame()' in that specification.	工作草案	初始定义。

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
grabFrame	Chrome 59	Edge ≤79	Firefox ?	IE ?	Opera 46	Safari ?	WebView Android 59	Chrome Android 59	Firefox Android ?	Opera Android 43	Safari iOS ?	Samsung Internet Android 7.0

图例

完整支持

完整支持

兼容性未知 ?

兼容性未知

实验。期望将来行为有所改变。

实验。期望将来行为有所改变。

元数据

• 最后修改： Feb 11, 2020

相关话题

1. ImageCapture
2. 构造函数

   1. ImageCapture() constructor
3. 特性

   1. track
4. 方法

   1. getPhotoCapabilities()
   2. getPhotoSettings()
   3. grabFrame()
   4. takePhoto()
5. 继承：

   1. EventTarget