private ColorPalette palette(Octree tree, ColorPalette old, int maxColors)
{
ArrayList palette = tree.palette(maxColors - 1);
for (int i = 0; i < palette.Count; ++i)
old.Entries[i] = (Color)palette[i];
old.Entries[maxColors] = Color.FromArgb(0, 0, 0, 0);
return old;
}