I’ve just uploaded the latest in my series of articles about using
RMagick. This one explains a very simple technique for creating a
digital watermark that looks like embossed text. I hope you find it
useful.
http://rmagick.rubyforge.org/watermark/watermark.html
The RMagick home page has links to the entire series:
http://rmagick.rubyforge.org.
RMagick is an interface to the ImageMagick (http://www.imagemagick.org)
and GraphicsMagick (http://www.graphicsmagick.org) image processing
libraries that supports more than 90 image formats, including GIF, JPEG,
and PNG. RMagick includes RVG, a 2D drawing API. Comprehensive HTML
documentation for RMagick is available here:
RMagick 1.15.0 User's Guide and Reference and here:
http://studio.imagemagick.org/RMagick/doc/.