[Magick-bugs] quantize introduces black areas (confirmation ofalready posted bug)

[Till Oliver Knoll]

Till Oliver Knoll schrieb:
> Till Oliver Knoll schrieb:
> ...
> Summary:
> 
> - 6.2.9 works with quantum depth 16 (Linux, Windows)
> - 6.2.9 does NOT work with quantum depth 8 (Windows, did not try Linux)
> - 6.3.x does NEVER seem to work (tried 6.3.4 and 6.3.5 on both Windows
>                                  and Linux, 6.3.2 only on Linux;
>                                  Windows: tried with both Q8 and Q16;
>                                  Linux: tried Q16 only (default))

Oh noooo! The 6.2.9 Q16 works with my alpha254.png test image, but I 
have this GREYSCALE image of a person's face with an alpha uniformly set 
to 254 (due to another bug in the Trolltech Qt 4.3.1 smoothScale() 
method) and this ALSO produces a "black area", in the area where the 
background is supposed to be very bright (almost white).

In other words: The 6.2.9 Q16 (Windows) is ALSO BUGGY (but at least 
partially better than the 6.3.x).

I tried to reproduce this case with an artificial greyscale ramp image 
with an alpha set to 254, but I could not yet reproduce this (the 
greyscale ramp 256x256 image WORKS!).

I will try to upload my test images somewhere and let you know.


Cheers, Oliver