Color half image

[CrispyCookie]

I would try this script to color the left half of my images green:

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convert leftgreen: image.png
convert leftgreen: -crop 32x32+0+0 -background green image.png

I haven't tried it yet, but there's a problem, since my images aren't always 64x32.

If you don't get what I want, I want the left half colored green (#00FF00) and retain the right half, at images which are either 64x32, 64x64, 128x32 or 128x64.

Is there a universal solution like

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convert leftgreen: image.png
convert leftgreen: -crop [fx:w/2]x[fx:h/2]+0+0 -background green image.png

?

Thanks in advance.

[fmw42]

this might be a little slow, but is the simplest

convert image.png -fx "i<=w/2?green1:u" image_leftgreen.png

see fx at http://www.imagemagick.org/script/fx.php


Here is the more complicated way:

convert image.png \
\( +clone -set option:distort:viewport "%[fx:w/2]"x"%[fx:h]"+0+0 \ -distort SRT "1 0" \
-threshold -1 -fill green1 -opaque white \) \
-composite image.png

[anthony]

Why not divide the image in two, color the left half and merge together again.

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   convert  image.png  -crop 50x100% \
               \( -clone 0 -fill green -colorize 100% \) \
               -delete 0 -background none -flatten  result.png

Or instead of layer merging, try append instead.

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   convert  image.png  -crop 50x100% +repage \
               \( -clone 0 -fill green -colorize 100% \) \
               -swap 0 +delete  +append  result.png

See IM examples Image Sequence Operators and tile cropping

Either method should work fine for any single image. Though their will be differences for images which already involve 'layer' or 'virtual canvas' handling. I don't think that would be the case however.