I've got a bit of a weird use case here; I'm trying to color a posterized heightmap I created with cloud effects and gradients, and to 'simulate' water flowing downwards (into darker colors) I was wondering if there was a way to have the paint bucket fill only into colors that are equal to or darker to the current pixel, does anyone know of a plugin to do this or a method to achieve the same effect? Or, in other words, I want to be able to select all contiguous pixels that are as dark or darker than the currently selected pixel.
