Exact Collision detection

Blitz3D Forums/Blitz3D Beginners Area/Exact Collision detection

Anyone know a quick way that I can determine if a rectangular area of the screen is EXACTLY the same as a test image? All of the Blitz collision detection routines check if ANY pixels collide - I want to know if all of them collide in, say a 32x32 rectangle.

As an example, in a painter-type game, I would like to determine if the outer edge of a rectangle is completely filled by comparing it against a previously filled block (maybe I just have to check the lines, somehow?)

Ta,