Hello

I use a script which insert some weather-infos into my wallpaper and then reload it. Now, if the wallpaper is dark, then the weather-infos are clear to see. (I insert it with alpha-blending (transparency)). But, if the wallpaper is bright, then I see only some things, but not clear. Now my question:

is there a way to assign the brightness in a number (like the digicams with their histogramm) from a shell-script?

Then I can calculate the transparency for the weather-infos...

I use Imlib2-Library (from perl) to work with the images, but I don't have any idea to measure the brightness...

Thanks for any help and idea.
Raphael