Rationale

This page is intended as a record of why some things have been done the way they are in the library, it will be expanded as more design decisions are made.

The default image file format: PCX

A file format was needed for images, one that was supported by image manipulation applications such as The GIMP, Image Magick or Graphics Magick, etc. It was also required to be simple to decode and preferably with some degree of compression, this is so a decoder could be written without any external dependencies, allowing AeonGUI to run standalone if required.

The PCX file format does have a downside though, it does not officially support an alpha channel, and since it is an ancient format, it is doubtful that it will be updated to do so. Unofficially however, because of how the file is structured, it is very simple to add an alpha channel without breaking the file specification, and this is how AeonGUI deals with the alpha channel on PCX files.

Both Image Magick and Graphics Magick support and can convert to and from PCX files with a 4th channel for alpha, but unfortunately the GIMP does not at the moment, the workaround for this, if you do want to use PCX images with transparency in your projects is to author them in your favorite image editor, export them as PNG and then use one of the Magick converters to get an AeonGUI compatible PCX file with alpha.