This loader gets pictures of the hardware freezer module and printing utility Diashow Maker to GoDot. Diashow pictures may have any conceivable screen format. GoDot supports multicolor graphics, hires graphics, and standard text screen mode. GoDot will load Diashow pictures even if they are provided with an autostart header (feature of Diashow). Sprites in graphics and multicolor text mode are possible but not supported by GoDot.
Diashow pictures are packed using the packbits algorithm. There are two indicators: $BF is followed by the number of repetitions of the next (third) byte, and $CF is followed by a counter for zero value bytes ($00). If there's a zero behind $BF or $CF, the indicators themselves have to be written to memory.
File structure: the autostart header has a length of 275 bytes, if present. The picture file totally occupies 13632 bytes, and starts by 8 times 64 bytes of sprite information. They are succeeded by twice 1024 bytes of color memory, relieved by the register area of the VIC, from which you can take the display mode and the appropriate sprite information (position, colors, etc.) This section has a length of 3072 bytes, and is followed by an 8192 bytes bitmap. If it is a text mode picture, it is followed by the character set instead of the bitmap. GoDot will transform text screens to hires pictures when encountering them. File names have a leading signature of C=B (ASCII 191), two following digits, and then the actual name. The start address of a file is $4000 ($0801 if autostart).
In the meantime there's a version 1.3 of the Diashow software (it is unlikely that the same author wrote it, because this version doesn't show some of the better properties of the "predecessor" anymore). Nevertheless: we wrote a loader for this format, too, in the meantime (ldr.Diashow1.3).
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Copyright © 1997, A. Dettke, Last Updated - 11/02/97