[Pixman] Make pixman compatible with big image

Søren Sandmann sandmann at cs.au.dk
Thu Sep 12 17:42:47 PDT 2013

LE GARREC Vincent <legarrec.vincent at gmail.com> writes:

> So, what should I do ? Is it okay to make a cast for every multiplication
> of stride by height ?

There are a couple of things that have to be kept in mind:

- The stride can be negative (this corresponds to the lines of the image
  being stored upside down), so storing or casting the stride to size_t
  probably won't work.

- Even if you fix the multiplication issues, has limitations in other
  places that prevents access to large images working well. See


  for example. Fixing the multiplications may still be worthwhile
  though, since we may some day get large images working.

> I'm asking because I don't want to work on a patch that will be denied
> because my solution is wrong.

I don't know what the best way to do it is, but requiring all rowstride
multiplications to have a cast probably isn't going to be maintainable,
because people will forget about it when writing new code.


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