Re: bug in image compositing in -xlib

[Alexander Malmberg]

Benhur Stein wrote:
> Hi!
> I reported a bug in image drawing some days ago.
> Well, I came back to it, and made a bad hack that corrects the problem.
> Also attached is the program I used to test and a screenshot of
> its execution in OS4.2 and GNUstep with back-xlib.
> I couldn't try on -art because I get a compilation error (ftfont.m:82:
> parse error before "FTC_ImageDesc"), 

This is a known issue with recent development versions of freetype. See
http://wiki.gnustep.org/index.php/FTC_Image_Desc .

> but I'm pretty sure -art does not have this bug.

It doesn't; results match those in the OS4.2 screenshot.

[snip]
> the variable viewIsFlipped cannot be trusted

That's true, it shouldn't be used. Is there any particular reason why it
hasn't been removed completely yet?

> (and I only found a reference to it
> in the windows backend), so I accessed the ctm directly.
> I know it is a bad hack, it is ugly, it should be solved differently,
> but it seems to work and I do not have time to make a better 
> solution...

Looking at the ctm isn't a hack, it's the correct way of doing it. Of
course, to be completely correct, you need to handle arbitrary ctm:s. :)

Anyway, I'm not very familiar with -xlib, but if it correctly handles
all combinations of flipped and unflipped views (ie. results match those
on OS), it should be correct enough to handle almost everything -gui
itself will ever do.

- Alexander Malmberg