About Image File Formats

The background image files used by some of the wireless models use an older format called Binary IMage (BIM) format, usually denoted by the .bim suffix. The format has one advantage for wireless models: it is not re-sizable. Because it maps pixel-for-pixel to the screen, sub-segments can be easily re-drawn when wireless "beams" are removed or nodes move. Refreshing sub-segments of large images is efficient and eliminates distracting flicker.

A better method is now to use PPM images with the fixed-size image draw routines. But the following are provided for backward compatibility to old models.

Making BIM files - To convert an ascii color PPM image file to .bim format, use PPM2BIM. (Right-click to download.) Compilation and usage instructions are provided in the header.
Bit Reversing BIM files - BIM files, being binary files, are sensitive to big-endian/little-endian architecture issues. For example, BIM files for Sun are not compatible with Intel. The indication if you encounter this, is that the image read-in routine will state that it is reading an image of ridiculous size (ex. 189292992 x 737382819), and then proceed to crash. (Normally it should report something like 680x480, or something your screen can support.) To bit-reverse a BIM file to transfer across architectures, use Bit_Reverse. (Right-click to download.) Compilation and usage instructions are provided in the header.