On Jul 9, 2009, at 4:19 PM, Gregg Tavares wrote:
On Thu, Jul 9, 2009 at 4:11 PM, Oliver Hunt <oli...@apple.com> wrote:
I'd like to make a passionate plea that the spec say
"implementations must
support negative widths and negative heights and draw the image
backward
effectively flipping the result".
We'd need to be fairly sure that such a change would not break
existing content -- this is a change that would result in
substantially different rendering in some scenarios.
Given that it's inconsistent in the various browsers it's hard to
see how this would break something since it's broken in 2 browsers
one way or the other currently.
Inconsistency doesn't lead to no one depending on a behaviour, it just
means sites only work in one browser. Your suggesting would result in
sites being broken in all browsers -- the only options from here on
out are either nothing gets drawn (as in gecko and presto), or the
destination is normalised (as in webkit)
Image scaling is implementation dependent everywhere else, why would
it be spec defined in the case of canvas?
There are 2 issues here I brought up
1) What happens at the edges.
The results are VASTLY different now. Unless this works consistently
it would be hard to make canvas graphics work across browsers and
expect get reproducible results. The 2x2 pixel example I gave, one
browser ends up scaling with translucency even though there is no
translucent pixels in the source image.
This is just an artifact of scaling, and you agree below that scaling
is implementation dependent.
2) How it does the scaling.
I agree that it being implementation dependent is probably fine.
--Oliver
