Bug#564111: [Fwd: gimp-dds: problems with the box scaling]

[Vincent Fourmond]

  Hmmm... Maybe it is time for sleep, after all ?

	Vincent

-------- Original Message --------
Subject: gimp-dds: problems with the box scaling
Date: Sun, 07 Mar 2010 00:51:29 +0100
From: Vincent Fourmond <fourmond at debian.org>
To: skirst at insightbb.com
CC: 564111 at debian.org


  Hello,

  I'm the Debian Developer who packages your neat gimp-dds plugin for
the Debian distribution (http://www.debian.org). I've had a user
complain about 1x1 and possibly 2x2 mipaps not generated correctly; you
can see the bug reports there:

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=564111

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=564113

  I've had a closer look at it, and it seems that the scale_image_box is
somehow not doing the right thing for the lower limit of the pixel size.
See: if sw = sh = 2 and dw = dh = 1, we have for x = 0, y = 0 (the only
pixel) ix = 1 and iy = 1, which means that the code, which is looking at
ix, iy up to ix+1, iy+1 is looking at a non-existing pixel (2,2).

  I'm unsure how to modify the code, simply using

  iy = (y * sh + sh / 2 - 1) / dh;

  would most probably work excepted when sh is 1 ?

  BTW, in this line

  ix = (x * sw + sh / 2) / dw;

  I guess you mean sw rather than sh, don't you ?

  I hope this helps.

  Many thanks again for making this plugin publicly available; it is
dead useful !

  The CC address is the (first) bug report's mailing list; if you wish
that your answer is recorded in Debian's bug tracking system, please
keep it in CC.

	Vincent

PS: I saw you've modified quite a bit the code since the 2.0.7 release
which is the one currently available, but it doesn't seem to me that the
bug is fixed in the current SVN version.

-- 
Vincent Fourmond, Debian Developer
http://vince-debian.blogspot.com/

find(1):
 A `%' at the end of the format argument causes undefined behaviour
 since there is no following character. In some locales, it may
 hide your door keys, while in others it may remove the final page
 from the novel you are reading.

Vincent, not listening to anything for now


-- 
Vincent Fourmond, Debian Developer
http://vince-debian.blogspot.com/

Comme dit mon tonton: plus on est de cons, plus ça se voit !
 -- La Tordue, Où va-t-on

Vincent, listening to Pull Me Under (Dream Theater)