Re: Affine transform on transparent image introduce black

On Sun, 4 May 2008, Tim Hunter wrote:

> The input image has transparent pixels. After the transform, the transparent
> pixels are partially black. Here's the command I used:
>
> gm convert  -affine 1,0,0.785,1,0,0 -transform before.miff after2.miff

At first I was deeply concerned by this bug since I thought that maybe 
it had been introduced into GraphicsMagick during development (i.e, 
cause for grave concern).  Testing shows that this issue has always 
existed in GraphicsMagick and was inherited from ImageMagick.

Testing with ImageMagick 5.4.7 shows that it had similar bugs except 
that it lightened the pixels rather than darkening them.

Bob
======================================
Bob Friesenhahn
[email protected], http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/


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