Question

I have a concave polygon stored as an Area. How would I flip/invert/mirror the polygon about the y-axis?

Answer 1

You can use the Area’s transform method. This takes an AffineTransform object which specifies a single affine transformation. For the case of flip you can define the following transform

AffineTransform at = new AffineTransform(new double[] {-1.0,0.0,0.0,1.0});