Re: Colorspace conversion?

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 8/16/06, neota@xxxxxxxxxxxx <neota@xxxxxxxxxxxx> wrote:
I've compiled and installed GEGL and BABL, and I just tried to edit
drop-shadow.xml,
replacing
<node class='load' path='data/vinci-fly3.jpg'/> with

<node class='load' path='data/test0.png'/>
to test colorspace conversion (test0.png is a 8bit greyscale image).
I've tried giving test0.png alpha channel or removing the alpha channel, but
in all cases this results:
(from running 'gegl drop-shadow.xml -o drop-shadow.png')


** (process:5857): WARNING **: color type mismatch

** (process:5857): WARNING **: calc have rect of data/test0.png failed

** (process:5857): WARNING **: color type mismatch

** (process:5857): WARNING **: GeglOpPlugIn-png_load is data/test0.png
really a PNG file?
Segmentation fault


The only case in which it works correctly is if I convert test0.png to RGB.
What is going on here?

The problem is that the png-load operator
(gegl/opertaions/file-io/png-load.c) isn't written in a generic enough
manner to handle anything but 8bit RGBA images. Ideally it should
check what type of image is stored, and use it with the correct pixel
format.

If someone sits down and rewrites the png loader to handle the pixel
format correctly what you tried to do should work. The loader I used
in gggl http://pippin.gimp.org/tmp/gggl-png-loader could probably be
mostly reused, but in babl the pixel formats corresponding to the
possible PNG pixel formats are:

"R'G'B'A u8"
"R'G'B' u8"
"Y' u8"
"Y'A u8"
"R'G'B'A u16"
"R'G'B' u16"
"Y' u16"
"Y'A u16"

Rewriting the png loader to handle 16bit/component would also mean
that the fallback mechanism using image magick (with the "load"
operation) would be able to handle other 16bpc formats as well, right
now the only way to get >8bit data into GEGL is using "raw-load" which
is a dcraw wrapper.

/Øyvind K.
--
«The future is already here. It's just not very evenly distributed»
                                                -- William Gibson
http://pippin.gimp.org/                            http://ffii.org/
_______________________________________________

Gegl-developer@xxxxxxxxxxxxxxxxxxxxxx
https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer


[Index of Archives]     [Yosemite News]     [Yosemite Photos]     [gtk]     [GIMP Users]     [KDE]     [Gimp's Home]     [Gimp on Windows]     [Steve's Art]

  Powered by Linux