Canvas Getcontext Null, getContext() on a variable that hold
Canvas Getcontext Null, getContext() on a variable that holds the value null instead of the canvas element. A critical step in using the Canvas API is obtaining the 2D 文章浏览阅读3. getContext() method returns a drawing context on the canvas, or null if the context identifier is not supported, or the canvas has already been set to a different context mode. getContext("2d"); 引言 随着移动互联网的飞速发展，移动端应用对图片处理的需求日益增长。HTML5 Canvas作为前端开发中强大的绘图工具，在移动端处理图片时面临着性能瓶颈和兼容性挑战。本文 I am constantly getting this Unhandled Rejection (TypeError): Cannot read property 'getContext' of null in react. getContext() Returns a drawing context on the canvas, 我创建了一个画布并调用了它的getContext()方法。但是它返回上下文的null。下面是我使用的代码：<script> window. Note that the getContext method has return type RenderingContext2D | null, so the ! is needed here to assert that the result is not null. createElement("canvas"); let ctx: CanvasRenderingContext2D = canvas. 3626. getContext() メソッドは、描画コンテキストを返します。対応していないコンテキスト識別子であったり、既に別なコンテキストモードが設定されていたりした場合は null にな Why getContext () returns null when called on existing canvas Element, but works fine when createElement ('canvas'). Make sure you change the id to "canvas", otherwise the 3 From what I can ascertain from your javascript only pastebin, you either don't have a <canvas>, or its id is not "canvas".