Having realized that the encoding I proposed yesterday was quite naive,
I now propose a new encoding based on bzip2 compression, tentatively
called bz2tile.
The uncompressed representation starts with the tile size:
U16 tileSize;
As with Hextile and ZRLE, if the dimensions of the rectangle aren't
exact multiples of the tile size, the last row and/or column of tiles
are smaller.
Each tile starts with a subencoding field:
U8 subencoding;
There are three subencodings:
0 - Raw:
The subencoding field is followed by the raw pixel data for the tile:
CPIXEL data[tileSize * tileSize];
1 - Solid:
The subencoding field is followed by the solid color of this tile:
CPIXEL solidColor;
2 - Palette:
The subencoding field is followed by the maximum palette index:
U8 maxIndex;
Since palette indices are zero-based, this is the size of the palette
minus one. This subencoding therefore allows a palette of up to 256
colors. This subencoding never packs multiple pixels into a single
byte; bit-packing is the job of the Huffman coder used by bzip2.
The maxIndex field is followed by the palette:
CPIXEL palette[maxIndex + 1];
The palette is followed by the indices for this tile:
U8 indices[tileSize * tileSize];
Any questions or concerns regarding this new encoding? I'm about to
implement it.
Matt
_______________________________________________
VNC-List mailing list
[email protected]
To remove yourself from the list visit:
http://www.realvnc.com/mailman/listinfo/vnc-list
