[Magick-bugs] ImageMagick-6.2.9-6-Q16 Windows DLL : Alpha channel ignored

[Walter Higgins]

This problem is still apparent in build 6.2.9-6 

The alpha channel is 1-bit. pixels are either on or off .

Walter Higgins

----- Forwarded Message ----
From: Walter Higgins <walterh at rocketmail.com>
To: magick-bugs at imagemagick.org
Sent: Thursday, September 14, 2006 10:45:11 PM
Subject: [Magick-bugs] ImageMagick-6.2.9-5-Q16 Windows DLL : Alpha channel ignored

Hi,  
  
I use ImageMagick with perl and I've recently upgraded to 6.2.9-5-Q16 from 6.2.5-4 and now a lot of my image operations won't work.  
  
It appears that any operations which rely on the use of the Alpha channel and gradients are broken.  
  
Taking the example of  "Using a Compose Mask to Limit the Composed Area" from Anthony Thiessen's page...  
  
http://www.cit.gu.edu.au/~anthony/graphics/imagick6/compose/  
 
I create a gradient image ... 
 
convert -size 100x100 gradient: gradient.gif 
 
then use that gradient as an alpha mask when composing two images (see anthony's page for the sample images)... 
 
composite tile_water.jpg   tile_aqua.jpg  gradient.gif   mask_over.png 
 
What this should do is create a gradual vertical blend from tile_water.jpg to tile_aqua.jpg but the result... 
 
imdisplay mask_over.png  
 
...shows that the gradient.gif has been ignored ! 
 
Note that this works fine with the moon_mask.gif image in Anthony's page. It's just gradients that cause problems. 
 
This works fine in 6.2.5 so I'm wondering - any idea when this will be fixed ? 
 
Walter Higgins 
 
  
 


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