ImageMagick colorize command in Linux

Question

I need to change an icon color in a png file, where the icon has a transparent background.

I used the following ImageMagick command:

 convert my_icon.png -fill #de2a2a" -colorize 100 output1.png

In Windows, the command colors the icon without the transparent background.

In Linux, it colors "all the icon" including the transparent background.

Why does this happen? How can I solve this problem in Linux?

The ImageMagick version:

Windows: ImageMagick 7.0.4-10 Q16 x64
Linux: ImageMagick 6.7.8-9 2016-06-16 Q16

The Icon:

Thanks

I have 3 suggestions... 1) post the *actual* command you use, 2) post representative images, 3) show the versions of **ImageMagick** you use on both platforms. — Mark Setchell, Apr 23 '17 at 08:47
1)the command:convert my_icon.png -fill #de2a2a" -colorize 100 output1.png — Yosefarr, Apr 23 '17 at 09:08
That command cannot work - the `#` will cause the latter half to be treated as a comment and you have an unbalanced `"`. — Mark Setchell, Apr 23 '17 at 09:18
sorry my fault:convert my_icon.png -fill "#de2a2a" -colorize 100 output1.png — Yosefarr, Apr 23 '17 at 09:22
The obvious answer would be to upgrade your 4 year old ImageMagick on Linux. You could try this maybe though as a workaround `convert my_icon.png -channel RGB -fill ...` and see if that helps. — Mark Setchell, Apr 23 '17 at 09:23
Or you could try `convert my_icon.png -fill '#de2a2a' -colorize 100 my_icon.png -compose copyopacity -composite result.png` — Mark Setchell, Apr 23 '17 at 09:26
The problem was fixed after upgrade to ImageMagick 7.0.5-4, thanks for your help — Yosefarr, Apr 23 '17 at 13:04

score 2 · Answer 1 · answered Aug 29 '19 at 15:18

On Ubuntu 18.04 (ImageMagick 6.9.7-4) the issue is no longer reproducible. Also tested on MacOS 10.14 (ImageMagick 7.0.8-47).

Command:

convert ~/Desktop/phone.png -fill "#de2a2a" -colorize 100 ~/Desktop/phone-red.png

Note, you have a typo in your command...

-fill #de2a2a"

Should be: (double-quote before the #)

-fill "#de2a2a"

score 1 · Answer 2 · answered Aug 29 '19 at 16:03

I think you have your Windows and Linux versions swapped.

In ImageMagick 6, -colorize only affects the RGB channels and not the alpha. But in ImageMagick 7, -colorize affects all the channels including alpha. So for IM 7, turn alpha off, then colorize, then turn it on again. (Be sure to put quotes on both sides of your hex color)

For IM 7,

magick my_icon.png -alpha deactivate -fill "#de2a2a" -colorize 100 -alpha activate output1.png

Note that deactivate and activate are the IM 7 equivalents of off and on in IM 6

See porting guide

ImageMagick colorize command in Linux

2 Answers2