Degas: Difference between revisions
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* Company: [[Integral Solutions]] | * Company: [[Integral Solutions]] | ||
* Extensions: .pi1, .pi2, .pi3, .pc1, .pc2, .pc3 | * Extensions: .pi1, .pi2, .pi3, .pc1, .pc2, .pc3 | ||
'''DEGAS''' (short for ''Design & Entertainment Graphic Arts System'') and '''DEGAS Elite''' were image drawing programs for the [ | '''DEGAS''' (short for ''Design & Entertainment Graphic Arts System'') and '''DEGAS Elite''' were image drawing programs for the [http://en.wikipedia.org/wiki/Atari_ST Atari ST]. | ||
__TOC__ | __TOC__ | ||
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==Hardware Palette== | ==Hardware Palette== | ||
The Atari ST has 16 16-bits hardware palette registers. All 16 colors are always stored, even if the resolution does not use them all. | The [http://en.wikipedia.org/wiki/Atari_ST Atari ST] has 16 16-bits hardware palette registers. All 16 colors are always stored, even if the resolution does not use them all. | ||
Each color is specified as: | Each color is specified as: | ||
0000 0rrr 0ggg 0bbb | 0000 0rrr 0ggg 0bbb | ||
A standard Atari ST has a 9-bit DAC, which results in 512 colours. | A standard [http://en.wikipedia.org/wiki/Atari_ST Atari ST] has a 9-bit DAC, which results in 512 colours. | ||
[[Category:Image Formats]] | [[Category:Image Formats]] | ||
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Revision as of 18:24, 26 April 2008
- Company: Integral Solutions
- Extensions: .pi1, .pi2, .pi3, .pc1, .pc2, .pc3
DEGAS (short for Design & Entertainment Graphic Arts System) and DEGAS Elite were image drawing programs for the Atari ST.
DEGAS
- Extensions: .pi1, .pi2, .pi3
typedef DEGASFile { uint16_t resolution; /* 0 = low res (320x200x16), 1 = medium res (640x200x4), 2 = high res (640x400x2) */ uint16_t hardware_palette[16]; uint16_t data[16000]; } DEGASFile; sizeof(DEGASFile) = 32034
DEGAS Elite (Uncompressed)
- Extensions: .pi1, .pi2, .pi3
typedef DEGASEliteFile { uint16_t resolution; /* see above */ uint16_t hardware_palette[16]; uint16_t data[16000]; uint16_t left_color_animation[4]; uint16_t right_color_animation[4]; uint16_t channel_direction[4]; /* 0 = left, 1 = none, 2 = right */ uint16_t channel_delay[4]; /* 128 - channel delay, timebase 1/60 s */ } DEGASEliteFile; sizeof(DEGASEliteFile) = 32066
DEGAS Elite (Compressed)
- Extensions: .pc1, .pc2, .pc3
typedef DEGASEliteFileCompressed { uint16_t resolution; /* see above */ uint16_t hardware_palette[16]; uint16_t data[]; /* size depends on compression ratio */ uint16_t left_color_animation[4]; uint16_t right_color_animation[4]; uint16_t channel_direction[4]; /* see above */ uint16_t channel_delay[4]; /* see above */ } DEGASEliteFileCompressed;
Compression scheme: PackBits RLE
- The image is compressed from top to bottom
- Each scanline is compressed separately
- For every scanline, each bit plane is compressed separately, starting with the least significant bits
Hardware Palette
The Atari ST has 16 16-bits hardware palette registers. All 16 colors are always stored, even if the resolution does not use them all. Each color is specified as:
0000 0rrr 0ggg 0bbb
A standard Atari ST has a 9-bit DAC, which results in 512 colours.