I need to extract a custom shape from a given image. That custom shape can be, for example, a triangle.
For example, if source picture is 100px width and 100px heigth, I need to define a triangle with points:
(x=0 y=0) , (x = 50, y = 50), (x = 0, y = 50)
I have found many examples for extracting a rectangle and also a circle, but I need to define, by declaring manually its points, a custom shape.
Thanks in advance