显示图像的画布从一个画布到另一个使用画布的base64 [英] Display canvas image from one canvas to another canvas using base64
问题描述
例如。 新变种= canvas.toDataURL(图像/ PNG);
我要为Base64就是在这个新的变量present要显示成是present第二canvas元素。不过,这并不使用drawImage方法显示的base64形象。
它的工作原理,如果我用说 image.png
I want the base64 that is present in this new variable to be displayed into 2nd canvas element that is present. But it does not display the base64 image using drawimage method.
It works if I use say image.png
推荐答案
您不应该使用的base64复制的画布。您可以将源画布传递到目标画布'上下文方法的drawImage。
You shouldn't use base64 to copy the canvas. You can pass the source canvas into the destination canvas' context method, drawImage.
否则,你将遭受严重的性能损失。见我jsperf测试在 http://jsperf.com/copying-a-canvas-element。
Otherwise you will suffer a serious performance hit. See my jsperf test at http://jsperf.com/copying-a-canvas-element.
的drawImage()
将接受画布
,以及一个图片
对象。
drawImage()
will accept a Canvas
as well as an Image
object.
试试这个:
//grab the context from your destination canvas
var destCtx = destinationCanvas.getContext('2d');
//call its drawImage() function passing it the source canvas directly
destCtx.drawImage(sourceCanvas, 0, 0);
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