Based on UX discussions, we want to support a colorize mode which can modulate (be blended against) the ordinary transfer function, rather than always replacing it.
So this code change adds a color palette RGBA LUT in addition to the main transfer function LUT, and an alpha parameter to control the blend amount. The color palette and regular LUT are always blended together. An alpha of 1 will use entirely the color palette, and an alpha of 0 will entirely use the regular LUT.
Based on UX discussions, we want to support a colorize mode which can modulate (be blended against) the ordinary transfer function, rather than always replacing it.
So this code change adds a color palette RGBA LUT in addition to the main transfer function LUT, and an alpha parameter to control the blend amount. The color palette and regular LUT are always blended together. An alpha of 1 will use entirely the color palette, and an alpha of 0 will entirely use the regular LUT.