在主要浏览器中，亚像素精度的当前状态是什么?

I'm working on a drawing application which requires high levels of accuracy, and I'm wondering which of the major browser platforms (including the HTML Canvas element, and Flash) give the best sub-pixel layout accuracy, both for drawn elements (rectangles in the Canvas or Flash, absolutely positioned DIVs in the browser), and for text. I'm working on a drawing application which requ