This page contains utilities.

Making bitmaps transparent

Cu_alpha is a very small and simple utility for creating transparent bitmaps.

What it does

Cu_alpha makes one color of a bitmap transparent. Being a bit more precise: ca_alpha eats all .tif and .bmp files from a directory and writes .png files in a lossless way into another directory with either black or white as transparent alpha channel.

Uses

Ortho rectified images have empty borders you don want to see in your CAD program so you make these borders transparent. Other uses: Make logo's transparent for web use. Make scanned black and white drawings transparent. Etcetera.

The program is nothing more than a batch file used to generate some input panes and to tell convert.exe what to dow. The batch file relies on two programs: "ImageMagick" and "The Wizard's Apprentice". Credits go to these projects, url's: http://www.imagemagick.org/ and http://wizapp.sourceforge.net/.

Limitations

Only a Windows version. If source files share the same name with a different extension, only .bmp will be processed. abc.tif and abc.bmp will be transformed to abc.png where abc.tif is ignored.

Installation

No installer, download, unzip (to for example c:\bin\), make a desktop shortcut to cu_alpha.bat and drag the shortcut to your start menu.