* color depth = SUM(var->{color}.length)
*
* Pseudocolor:
- * var->{color}.offset is 0
- * var->{color}.length contains width of DAC or the number of unique
- * colors available (color depth)
+ * var->{color}.offset is 0 unless the palette index takes less than
+ * bits_per_pixel bits and is stored in the upper
+ * bits of the pixel value
+ * var->{color}.length is set so that 1 << length is the number of
+ * available palette entries
* pseudo_palette is not used
* RAMDAC[X] is programmed to (red, green, blue)
* color depth = var->{color}.length