★ APPLICATIONS ★ CREATION GRAPHIQUE ★ ADVANCED ART STUDIO SCREEN EXPANDER (CPC COMPUTING) ★ |
| Advanced Art Studio Screen Expander (CPC Computing) | Applications Creation Graphique |
PROGRAM I is for those of you with Rainbird's Advanced Art Studio. It displays the saved screens from AAS, even those which have been compressed. This means that you can compress your screens to save room on your discs, and still use them outside the AAS environment. Palette files - .pal — are read (if present) to set up the correct mode, ink values and flash rate. It is always best to save a .pal file with your screens even if you don't change the ink values because the AAS default colours are different to Basic's. Lack of a .pal file can therefore result in the screen looking odd. The only real difference between my palette display routine and the one in AAS is the way flashing colours are handled. AAS allows a sequence of 12 colours for each ink, but Basic does not support this. My version only reads the first and seventh in the sequence to allow normal two-ink flashing. Although the utility is in machine code, it must be used in conjunction with some Basic which can easily be incorporated into a larger program. The important lines are 60, which lowers HIMEM and loads the machine code, line 90, which pokes the filename into memory, line 100, which calls the machine code, and line 110 which reads the exit conditions. If location 20415 holds 255, the screen was not displayed due to a loading error. If it holds zero, the screen was drawn successfully. The maximum length of a Basic program is restricted to about 19K due to the machine code locating at 20000. It isn't really possible to locate it any higher as the screens (which are loaded above the machine-code) would run out of the memory pool, probably resulting in a crash. CPC Computing
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