Calamus Raster Graphic file format

Calamus Raster Graphic *.CRG

10 bytes file id [”CALAMUSCRG”] 1 word version? [$03E8] 1 word version? [$0002] 1 long file size, minus 24 1 word code for the page size? [$0080] 1 long image width in pixels 1 long image height in pixels 1 long unknown [varies] 1 byte unknown [$01] 1 byte unknown [$00] 1 long unknown [$FFFFFFFF] 1 long size of compressed image data in bytes

---

42 bytes total for header

?? monochrome image adata

RLE compression scheme: The compressed data consists of a code byte, followed by one or more data bytes, followed by another code byte, and so on.

 To decompress:  Code byte (N)    Instructions
                 N <= 127         Emit the next N+1 bytes literally.
                 N >= 128         Emit the next byte N?127 times.
                 
 After decompression, pixels are in left-to-right, top-to-bottom order. The format is
 8 pixels per byte, most significant bit first, white is 0. Rows are padded to the next
 byte boundary.