Filling the regions according to RGB values

Hello, I want to fill the regions according to their RGB values.In other words, i have a colored mesh structure obtained from Karamba. And i obtained the boundaries of the colored mesh which can be seen in the below figure.

I want to fill the region starts from yellow region placed on left side and ends at the other yellow region placed at right side by using linear lines. Also i want to do this action for the orange color region and for the others. You can see what i want to do in below figure. (Below figure belongs to another trial. So the colored regions are different from the above figure. But below figure defines what i want to do.)

I think this can be easily done by using Python but i have no idea how i can do. I know the RGB values of the colors. Actually, i obtained the region boundaries by using the RGB values of the mesh points.

Could u please help me about it?