When images are exported at a different color depth there are
different ways of choosing the colors that should be used for the
image. We provide the following options for the palette
- "Adaptive" - the default
The Adaptive palette may use fewer than the number of colors
specified if there are a limited number of colors in the image.
ImageGlue uses an optimised Octree algorithm for fast, high quality
The WebSafe, Windows and Macintosh palettes all have a fixed
numbers of colors. The depth parameter is ignored if you choose one
of these options.
The Uniform palette specifies a set of colors uniformly
distributed throughout color space. This palette only exists for 8,
27, 64, 125 and 216 colors and so the number you specify in the
depth parameter may be reduced to accomodate this.
The Grayscale palette will use exactly the number of gray values
specified in the depth - minimum two.
Black and White is always two colors - black and white.
The Exact palette is a kind of Adaptive palette optimized to
ensure an exact color match wherever possible.
You can append colors to Exact or Adaptive palettes separated by
colons or semicolons. These colors are fixed colors which will
always be added to the palette. For example the following code
would use a 32 color exact palette ensuring the colors black,
white, red and green were present.
c.ReduceColors "exact:255,255,255;0,0,0:#FF0000:#00FF00", 32,