Watermark color depending on the background

[AKapaceb]

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!

[snibgo]

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.

[AKapaceb]

Debian 8

[snibgo]

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%)"