David Vanderson on wrote... | Hello, | | Does anyone have a suggestion for how to select everything that's not a | specific color? | | For instance, in the following command I'm trying to make everything but | magenta transparent: | convert -channel "RGBA" -colorspace "rgb" in.png +matte -transparent | "magenta" -fill "black" -colorize "100%" -background "magenta" -flatten | -transparent "black" out.png | | This does work but seems overly complicated. I'm hoping there's a more | straightforward way. | There is currently no negated -opaque operator. You also do not need the -channel or the -colorspace options in the above.
So the above basically uses the selected color as a mask to invert the result. An alturnative is to use the NEW change_mask composite operator.. Which I added to IM v6.3.4 http://www.imagemagick.org/Usage/compose/#changemask convert in.png \( +clone +matte -fill magenta -colorize "100%" \) \ -compose ChangeMask -composite out.png This compares each color in the in.png with another 'all magenta' image that is the same size, and makes anything that is the same transparent. That is what is magenta is cleared. To invert, compare the image to itself, but with the magenta colors changed, to anything else! convert in.png \( +clone -fill black -opaque magenta \) -compose ChangeMask -composite out.png The parts of the first (original) image that changed color (magenta areas) will be returned. You can check if your IM has this Alpha Composition method using... convert -list composite | grep ChangeMask It was added to allow changes from one frame to the next to be detected and simplified for a new GIF Animation Compression Optimization, "-layers OptimizeTransparency" to make animation file sizes smaller. http://www.imagemagick.org/Usage/anim_opt/#opt_trans It was also incorperated into the General GIF Optimizer operator... "-layers Optimize" http://www.imagemagick.org/Usage/anim_opt/#optimize Anthony Thyssen ( System Programmer ) <[EMAIL PROTECTED]> ----------------------------------------------------------------------------- If everything seems to be going well, you obviously don't know what the hell you are doing. ----------------------------------------------------------------------------- Anthony's Home is his Castle http://www.cit.gu.edu.au/~anthony/ _______________________________________________ Magick-users mailing list [email protected] http://studio.imagemagick.org/mailman/listinfo/magick-users
