I have an image of a data center (like a building diagram). I want to color certain blocks in this image with a specific color code which is obtained based on certain computations for each block.

What is the most effective way to do that ? Any examples or code snippets would be of great help.

 I initially thought of manually replicating the diagram using functions like rect() but it seems tedious to manually enter (x,y) co-ordinates for all blocks of the detailed diagram.