Improve Foreground Selection Tool

by Jenny for GNU Image Manipulation Program

SIOX is the algorithm underlying GIMP's foreground selection. In current version, a pixel is either foreground or background. A Detail Refinement Brush will be offered to the user as a simple interactive drawing tool, with which the foreground selection could implement a soft segmentation. It would improve the performance of the tool for areas where background and foregound overlap, such as in fine-grained, highly-textured, or semi-transparent objects like hair, clouds, or iced objects.