This application uses very simple algorithm to process image. Every pixel in selected area is converted into grayscale then its brightness level and coordinates are
stored in a list. In case of colour selection, all selected pixels are filled with selected RGB color with their original brightness (For example see wall in image). In case
of texture selection a new image is created with fill type tile of selected texture. Now every pixel's brightness in this new image is adjusted based on original pixel's brightness
(For example see floor in image). In both cases user gets a real effect on image.