02-27-2022, 01:41 PM
The lasso/freehand defines a shape. When a pixel straddles the shape boundary, It is possible to determine how much of that pixel lies in the shape , and this is used to set a selection level and this partial selection translates into partial color blends which translate into smooth edges.
The Fuzzy selection (and the color selection) check if a pixel is selected or not depending on likeness (threshold slider) with the initial pixel. There is no notion of partial selection, so you get full color painting or no paint at all, and jagged edges. Very often what you want to do instead is working with color layers, replacing a color by transparency (Colors > Colors to alpha). See this for more details.
The Fuzzy selection (and the color selection) check if a pixel is selected or not depending on likeness (threshold slider) with the initial pixel. There is no notion of partial selection, so you get full color painting or no paint at all, and jagged edges. Very often what you want to do instead is working with color layers, replacing a color by transparency (Colors > Colors to alpha). See this for more details.