Replace color to same semi-transparent color

[kserradell]

Hello,

Sorry if the question is too simple but i've been trying to solve it without success.

This is my problem.

There's an image with some red regions (red is the example, but I want to set this color each time).

I want to get a new image with these same red regions, but with 50% transparent.

I use the following command:

Code: Select all

 convert red.png -matte -fill '#00000050' -draw 'matte 0,0 replace' semi_red.png

It works but only because there is a red color on 0,0.

How can I set a different color each time ??? Using 'green', 'red' or #0000FF ???

Thanks a lot !!!

KiM

[fmw42]

This will change white to half transparent white in the logo image so you can test it. You can change the color to any other rgba color. Note you must use .png for output as gif only supports binary transparency and jpg does not support any transparency.

convert logo: -channel rgba -matte -fill "rgba(255,255,255,0.5)" -opaque "rgb(255,255,255)" logot.png

If you want to include colors that are not exact, but nearby, then add -fuzz XX%

see
http://www.imagemagick.org/script/color.php

[kserradell]

fmw42,

thank you very much.

that's what I was looking for.

thanks again for you help !!!

KiM