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Stretching Polygon to other Polygon with Java

My problem is that I have a rectangle presented with a small perspective, and I would like to stretch it back to be presented as a rectangle again.

To represent it visually, I currently have within my image something like the red shape, and I have 4 Points (each corner of this shape). As result I would like to have something like the blue shape, and I already have the Rectangle object for it.

enter image description here

I was wondering if there is a method to copy a polygon and draw it as another polygon stretched. I found something for Android (setPolyToPoly), but I couldn't find something like this for java.

Is there some reference or code sample that performs this operation, or maybe some idea how can I solve this problem?

Solution

  • I think I understand what you need: a so-called perspective transformation that can be applied to an image. Java has the built-in AffineTransform, but an affine transform always preserves the "parallelness" of lines, so you cannot use that.

    Now if you search the web for "java perspective transformation", you will find lots of options like the JavaFX PerspectiveTransform, the JAI PerspectiveTransform. If you only need to stretch images, you can also use the JHLabs PerspectiveFilter and there are other options as well.