- canvas 大小限制
不同的浏览器对于canvas的大小是有限制的。超过大小将无法做任何写画的操作。
Updated 10/13/2014
All tested browsers have limits to the height/width of canvas elements, but many browsers also limit the total area of the canvas element. The limits are as follows for the browsers I’m able to test:
Chrome:
Maximum height/width: 32,767 pixels
Maximum area: 268,435,456 pixels (e.g., 16,384 x 16,384)
Firefox:
Maximum height/width: 32,767 pixels
Maximum area: 472,907,776 pixels (e.g., 22,528 x 20,992)
IE:
Maximum height/width: 8,192 pixels
Maximum area: N/A
IE Mobile:
Maximum height/width: 4,096 pixels
Maximum area: N/A
Other:
I’m not able to test other browsers at this time. Refer to the other answers on this page for additional limits.
Exceeding the maximum length/width/area on most browsers renders the canvas unusable. (It will ignore any draw commands, even in the usable area.) IE and IE Mobile will honor all draw commands within the usable space.
- canvas 清屏
2.1 ctx.clear(0,0,width,height)–第一种方法
2.2 ctx.canvas.width = width; ctx.canvas.height = height –第二种方法。这种方法会清除ctx绘图信息，比如字体，颜色等。