It really is a useful tool, and I agree that adding custom color selection for each value zone would make it even better. Being able to assign specific colors could help users quickly understand different ranges and improve visual clarity when analyzing data or patterns. Small UI improvements like that can make a big difference in usability. If you enjoy visual and color-based puzzle experiences, you might also like Block Blast, where arranging colorful blocks to clear rows and columns becomes surprisingly strategic and addictive. You can try a simple browser version here: https://blockblastonline.com

I'm assuming you mean the color would be assigned to the output? What would be the use case for this? Is this something you do already with other tools? Would It only be useful for subjects where there is just one local color like a sculpture? In a landscape where the blue sky and green grass are the same value, you would have to assign that value either blue or green. How would you pick?

It should be possible to select any color for each value zone, to produce what some call a "heatmap".