This component contains general parameters for the GIF image(s) contained in the file. Stored as a series of 8-bit byte values, these parameters are outlined in the table below.
|
Bits 7 6 5 4 3 2 1 0 |
Byte # |
Description |
|
Screen Width |
1 |
Raster width in pixels (LSB first) |
|
|
2 |
|
|
Screen Height |
3 |
Raster height in pixels (LSB first) |
|
|
4 |
|
|
M | cr | 0 | pixel |
5 |
M=1, global color map follows descriptor |
|
|
|
cr+1 = number of bits of color resolution |
|
Background |
6 |
Background = color index of screen background (the color is defined from the global color map or default map if none is specified |
|
Reserved Byte |
7 |
Set to zero |