Legacy ImageMagick Discussions Archive

I don't understand your comment about pre-multiplication. There is no pre-multiplication (by alpha, of the colour channel) in the command I gave. Perhaps it is simpler for you to supply inputs, with the desired output. From what I have been testing all day on c++, C# (BitMap, WriteableBitmap), Imag...

Imagemagick only supports one alpha channel in IM 6. IM 7 does support more than one alpha channel, but you cannot write that out to any common image format. You can combine alpha channels from two images and apply that one alpha channel to either of the two images. Typically you extract both alpha...

Assuming the images are the same size: convert imageA.png imageB.png -alpha off -compose CopyOpacity -composite out.png ... out.png will be given the colour channels from imageA.png, and the alpha from imageB.png. Thanks so much! This is in fact what I had before but I am missing color data on the ...

Most colour images have 3 channels, so I'm not clear what you want to do. If both images have no alpha ("-alpha off"), the grayscale is copied to the alpha channel. Thanks for help, Yes I have a PNG with RGB and Alpha and I am trying to copy ImageA.PNG to ImageB.PNGs alpha channel. Or mer...

I'm looking to take one image and clone it to another images alpha channel. I have been looking around this place as well as the Examples and have only found Copy_Opacity but I think this only handles the alpha of the image and not the actual channel.

Any help would be great!