Legacy ImageMagick Discussions Archive

Hello Friends!

Help me with command...

How can determine the color of a particular selected area in the picture, so that later i can insert a watermark depending on the background color. If the color background is light, then insert a black watermark. Or if the background color is black, then insert the lighter!

Some examples:

Thank you so much!

What version of IM, on what platform?

The basic idea is to crop the desired rectangle, and find the average lightness. If this is less than 50% (or whatever threshold you want) the text will be white, otherwise black.

With v7 this can probably be done in one command. In v6 it will need a shell script.

Debian 8

For example, bash syntax:

Code: Select all

PERCENT=$(convert \
  toes.png \
  -gravity East \
  -crop 40x200+0+0 +repage \
  -format "%[fx:mean<0.5?100:0]" \
  info:)

For the fill in the command that annotates or labels the image, use:

Code: Select all

-fill "gray($PERCENT%)"

Legacy ImageMagick Discussions Archive

Watermark color depending on the background

Watermark color depending on the background

Re: Watermark color depending on the background

Re: Watermark color depending on the background

Re: Watermark color depending on the background