transform2d 
written by Nobuyuki Umetani

build:
use CMake (https://cmake.org/) to build
it needs Eigen (http://eigen.tuxfamily.org/) to be compiled.


+move four corner points of image to see how the 2D transformation is defined by four points.

+changing translation matrix
++select matrix element: left botton click in matrix window
++increase matrix element: up key
++decrease matrix element: down key

+hit space key to change images

Enjoy!

