Projective transform

Here is projective transform.
x'= (A1*x+B1*y+C1)/(A*x+B*y+C)
y'= (A2*x+B2*y+C2)/(A*x+B*y+C)

It's rather similar to simple linear.

Some properties:
1)If three points lie on the straight line before transformation, than they will be lie on the straight line after.

2)Each convex quadrilateral can be transformed to arbitrary convex quadrilateral with the help of one and only one projective transform. (It's very useful for transform parameters determination)

You can download c-file, dll-file, sample flames and Excel file with example of finding parameters for Projective-1 flame.

You can see some examples of this transform usage
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