This is a CodeLab port of @harold's NormalMapPlus plugin. It's functionally identical, except for some fixes, the slider controls having an extra decimal place (due to the way CodeLab works), and the addition of a brief Help menu. Though the code is functionally the same, it was somewhat rewritten. It's in the Stylize submenu.   The fixes are: 1) The ROI boundary pixels are handled correctly. 2) The normals are computed at the correct positions, rather than being