static int color_tree_has(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a)
{
  return color_tree_get(tree, r, g, b, a) >= 0;
}
static int color_tree_has(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a)
{
  return color_tree_get(tree, r, g, b, a) >= 0;
}