Changes

Format:SGX (SymbOS graphic files)

586 bytes added, 14:44, 30 May 2023
data compression
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===Extended 4 and 16 colour graphicpart===
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Please note, that currently there are some limitations:
* the maximum width for a 4 colour graphics graphic part is 1020 pixel* the maximum width for a 16 colour graphics graphic part is 508 pixel* 16 colour graphics graphic parts must always have an even width in bytes (2,4,...,254)
===Line feed===
This chunk has a length of 3 bytes and can be recognized with 255 in the first byte. Usually every graphic part will be linked right to the previous part. After a line feed the next graphic part will be linked below the first graphic of the previous "line".
 
===EOF===
[[Image:symbosSGX.jpg]]
 
==Graphic data compression==
 
Both simple and extended graphic parts can be stored in a compressed way.
Compressed data has to be stored in the following SymbOS-specific way, which is used for all kind of compressed data in SymbOS:
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00 4B last 4 bytes of the data (not compressed)
04 1W size of non compressed part at the beginning (usual 0)
06 ?B not compressed part of the data
?? ?B compressed part of the data without the last 4 bytes
using the "ZX0 data compressor" by Einar Saukas, see
https://github.com/einar-saukas/ZX0
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==See also==