- From: Arve Bersvendsen <arveb@opera.com>
- Date: Mon, 24 Apr 2006 11:53:34 +0200
[ Ian Hickson ]
>> I don't understand how these are supposed to work when the underlying
>> bitmap's device pixel space does not map 1:1 to the coordinate space.
[ Vladimir Vukicevic ]
> I'm not sure what you mean -- the coordinates here are explicit canvas
> pixels, and they specifically ignore the current canvas transform.
> So, given
> <canvas width="100" height="200"></canvas>
>
> the coordinates would be 0..99, 0..199.
Without expressing any other opinion at the moment, I'd just like to
clarify how Opera's implementation of getPixel/setPixel currently follows
the coordinate space, as Vlad is suggesting here, disregarding any
translation and rotation. Given the following script snippet:
gc =
document.getElementsByTagName('canvas')[0].getContext('opera-2dgame');
for ( var y = 50; y < 100; y++){
for (var x = 50; x < 100; x++){
gc.setPixel(x,y,"blue");
}
}
... with this CSS:
canvas {
width: 200px;
height: 200px;
border: 1px solid black;
}
and the following markup:
<canvas width="100" height="100">
we fill the bottom-right quadrant of the canvas, with a rectangle that is
comprised of 100x100 CSS pixels.
--
Arve Bersvendsen, Opera Software ASA
Received on Monday, 24 April 2006 02:53:34 UTC