问题描述
canvas 元素和方法 captureStream 的情况很奇怪.根据文档 HTMLCanvasElement 有一个方法 captureStream.但是我的 Angular6 应用声称没有这种方法.
I have weird situation with canvas element and method captureStream. According to documentation HTMLCanvasElement has a method captureStream. However my Angular6 app claims that there isn't such method.
所以这段代码不起作用:
So this code won't work:
let canvas: HTMLCanvasElement;
canvas = document.createElement('canvas');
let stream = canvas.captureStream(20);
第三行失败.
这段代码运行没有任何错误:
This code runs without any error:
let canvas: any;
canvas = document.createElement('canvas');
let stream = canvas.captureStream(20);
这怎么可能?我 100% 确定 HTMLCanvasElement 具有此方法，并且 document.createElement('canvas') 返回 HTMLCanvasElement.
How this is possible? I'm 100% sure that HTMLCanvasElement has this method and the document.createElement('canvas') returns HTMLCanvasElement.
推荐答案
根据MDN，看起来 captureStream 方法仍然是一个工作草案(截至 2021 年 6 月)，尽管并非所有主流浏览器都实现了它.这可能就是为什么它还不是 HTMLCanvasElement 的类型定义的一部分.
According to MDN, it looks like the captureStream method is still a working draft (as of June 2021), eventhough it is not implemented by all major browsers. That is probably why it is not yet part of the type definition for HTMLCanvasElement.
这篇关于HTMLCanvasElement 上未解决的方法 captureStream的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！