Re: [Gimp-print-devel] Printing RGB layers in B&W.

[Dave H. <da...@mi...>]

Keith Parks wrote:
> 
> Hi,
> 
> I have a peculiar problem with the latest CVS versions of the
> print plugin and gimp.
> 
> If I create a new RGB image in Gimp, add a new layer and then
> scribble something on it, when I come to print I get an odd
> behaviour.
> 
> The multi layer is detected and the export/merge-visible dialogue
> activated. I accept this and am presented with the new print
> dialogue.
> 
> My printer is an ancient Apple Laserwriter IINT and my system
> a SPARCstation 5 running Solaris 7.
> 
> I have the Postscript Level 1 options set on both print and file.
> 
> The test image was a white background with a rough fat black
> circle drawn on the top layer.
> 
> If I select b&w and print to a file, the results are not what I
> expect to see. The background is black and the circle inner/outer
> edges just show as dotted white lines.
> 
> If I use colour, the image displays just fine.
> 
> Does anyone else see this or can anyone explain what is happening.
> 
> Thanks,
> Keith.
> 

Yes, I can reproduce this on Gimp 1.0.4 with the latest print
plug in using either Postscript output or PCL output.

The problem seems to be that after you have merged the layers
(which you have to do by hand in Gimp 1.0.4), the image is
"RGB-Alpha". If you just draw on the background, the image is
"RGB" and works OK. So the problem is in "rgb_to_gray()" which
isn't handling the alpha channel properly.

Dave

-- 
Dave Hill, Kempston, Bedford UK		da...@mi...
Sicth munce ago, I cutn't evun spel enjuneer, and now I are one!