- From: Anne van Kesteren <annevk@opera.com>
- Date: Sat, 26 Jan 2008 00:05:56 +0100
On Fri, 25 Jan 2008 23:57:56 +0100, Oliver Hunt <oliver at apple.com> wrote: > Another thing that we need is some way to determine what the device > pixel->css pixel ratio is. Currently there's isn't even a real way to > tell that it's 1:1 -- you would have do do a fillRect(width-1, height-1, > 1, 1),; then getImageData(width-1, height-1, 1, 1) and see if they > match. Conceivably you could do this multiple times to estimate the > ratio, but it would be non-trivial. You can determine this by checking the height and width attributes on the ImageData object. If you get a 2x2 region and ImageData.width and .height return 4 you know there's a factor two scaling happening between canvas pixels and device pixels. What the factor is between canvas pixels and CSS pixels isn't really relevant (and easy to determine). -- Anne van Kesteren <http://annevankesteren.nl/> <http://www.opera.com/>
Received on Friday, 25 January 2008 15:05:56 UTC