TruePaint/Prism Paint file format
TruePaint *.TPI Prism Paint *.PNT 1 long $504e5400 'PNT\0' TruePaint Magic 1 word $0100 ???? file version 1 word palette_size Might be there in true color 1 word x_size 1 word y_size 1 word bits_per_pixel 1 word compression, $0000 uncompressed, $0001 packbits compressed 1 long picture_data_size = ((x_size+15)&0xffff0)*y_size*bits_per_pixel/8 (uncompressed) 108 bytes $0 --------- 128 bytes total for header 3*palette_size words Palette data, RGB, values 0..1000. The colors are in VDI order picture_data_size bytes The line length is a multiple of 16 pixels for all bit depths Interleaved bitplanes for bits_per_pixel<16 16 bit word per pixel for 16-bit pictures, RRRRrGGGGGgBBBBBb 24 bit is stored R, G, B in that order The prism paint compressed format uses the Packbits compression algorithm. For every scanline the bitplanes are compressed separately. The falcon high-color resolution (16 bit) is compressed as if there were 16 bitplanes, which there are not. The same rule applies to 24 bits per pixel. Additional information: The TruePaint manual describes the format as designed for high speed and only writes uncompressed files. Prism Paint on the other hand offers compression every time a file is saved with an alert box (yes/no).
See also PackBits Compression Algorithm
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