- From: Boris Zbarsky <bzbarsky@MIT.EDU>
- Date: Wed, 12 May 2010 09:15:07 -0400
- To: Brad Kemper <brad.kemper@gmail.com>
- CC: Brian Manthos <brianman@microsoft.com>, "www-style@w3.org" <www-style@w3.org>
> Why don't things less than half a device pixel round to zero (at least for used value)?
That depends on what you mean by "used" values.
In Gecko, you would have the following values for width, say:
1) Specified value (a pair of float and unit).
2) Computed value (an integer in units of 1/60 CSS px).
3) Used value for layout computations (an integer in units of 1/60 CSS
px).
4) Used value for painting (this depends on the device).
1-3 above are device-independent.
It looks to me, at a brief glance, that things less than 1/2 a device
pixel round to 0 at step 4. Before that, everything is
device-independent, so the concept of device pixel doesn't necessarily
make sense (there are some caveats to that with borders, but it's true
for most lengths).
-Boris
Received on Wednesday, 12 May 2010 13:15:42 UTC