How to draw a Perspective-Correct Grid in 2D

Question

I have an application that defines a real world rectangle on top of an image/photograph, of course in 2D it may not be a rectangle because you are looking at it from an angl

Answer 1

The most elegant and fastest solution would be to find the homography matrix, which maps rectangle coordinates to photo coordinates.

With a decent matrix library it should not be a difficult task, as long as you know your math.

Keywords: Collineation, Homography, Direct Linear Transformation

However, the recursive algorithm above should work, but probably if your resources are limited, projective geometry is the only way to go.