Re: master 8b7aaf3e56: Speed up GIF animations

[Po Lu]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> I want to copy the bitmap that we've already computed in an efficient
> way.  PUT_PIXEL would be way too slow.

Not that I know of.  But I suspect that this doesn't really matter since
gif_load is only called once when loading an image into the image cache.

Using memcpy cannot possibly be correct with X images either.  What if
the X server demands the image be byteswapped, has odd padding
requirements, doesn't have a concept of "bits per pixel" and/or "bytes
per pixel", or has different masks for various components of a ZPixmap?

The only reliable way to deal with that mess is to use XPutPixel or
XGetPixel.  (Which image.c abstracts away with the PUT_PIXEL and
GET_PIXEL macros.)