在画布上绘制时，图像会丢失 webkit 转换

发布于 2024-12-25 09:01:09 字数 583 浏览 3 评论 0原文

我正在对 img 应用 webkit 转换，然后我想将该图像绘制到画布上。当我应用代码时，图像显示了转换，但画布显示的图像就像转换之前一样......提前感谢任何想法......

          var canvas = document.getElementById("myCanvas");
          var context = canvas.getContext("2d"); 
          var wrkimg = document.getElementById("workingimg");

          wrkimg.onload = function()
                {
                   $(this).css('-webkit-transform', 'rotate(162deg)  scale(1,1) scaleX(1)');    
                   context.drawImage(wrkimg, 50, 50);                
                 }

          wrkimg.src = 'Appimages/Head1.png';

原文

I am applying a webkit transformation to an img then i want to draw that image onto a canvas. when i apply the code the image shows the transformations, but the canvas show the image like it was before the transformations... any ideas thanks in advance..

          var canvas = document.getElementById("myCanvas");
          var context = canvas.getContext("2d"); 
          var wrkimg = document.getElementById("workingimg");

          wrkimg.onload = function()
                {
                   $(this).css('-webkit-transform', 'rotate(162deg)  scale(1,1) scaleX(1)');    
                   context.drawImage(wrkimg, 50, 50);                
                 }

          wrkimg.src = 'Appimages/Head1.png';

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半透明的墙 2025-01-01 09:01:09

当您将图像绘制到 Canvas 时，您不会使用任何 webkit/CSS 转换来绘制图像。你只需绘制普通的旧图像即可。

但是，您可以将变换应用于 Canvas 上下文本身，然后绘制图像。

请注意，这与对画布应用任何类型的变换不同。只是画布上下文。

因此，您不需要执行 webkit 旋转转换，而是需要调用 context.rotate

context.rotate(162 * (Math.PI/180)); // works in radians so we gotta convert
context.drawImage(wrkimg, 50, 50);

请注意，这里缺少一个步骤。当您变换上下文时，您始终会根据上下文的左上角进行变换，因此通常您必须结合使用平移和旋转才能获得所需的效果。

以下是使用画布上下文围绕其中心旋转图像的示例： http://jsfiddle.net/Wyw8p/

When you draw an image to the Canvas you do not draw the image with any of its webkit/CSS transforms. You just get to draw the plain old image.

However you can apply transforms to the Canvas context itself and then draw the image.

Note that this is not the same as applying any kind of transform to the Canvas. Just the canvas context.

So instead of doing a webkit rotate transform you'll want to call context.rotate

context.rotate(162 * (Math.PI/180)); // works in radians so we gotta convert
context.drawImage(wrkimg, 50, 50);

Note that there's a step missing here. When you transform a context you are always transforming by the context's top-left corner, so typically you'll have to do a combination of translation and rotation to get what you want.

Here's an example of an image rotated about its center using the canvas context: http://jsfiddle.net/Wyw8p/

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