07-21-2020, 09:01 AM
If it is a one-off then use the quick mask to make the selection. 0ne pixel pencil for hard edges - go round the edge to make the selection you want.
Otherwise, and no guarentee for other shapes
Make the initial selection
Shrink the selection by 2 pixels
Grow the selection by 1 pixel
Then up to you how you change to a border, this example, use the alpha-lock, invert the selection.
https://i.imgur.com/y3iXPNY.mp4
notes:
The anti-alias toggle is in the tool-options. If you have closed the tool-options dock, then don't, reinstate it.
Don't know version of Gimp you are using? In the Help menu -> About It will tell you in big letters.
Otherwise, and no guarentee for other shapes
Make the initial selection
Shrink the selection by 2 pixels
Grow the selection by 1 pixel
Then up to you how you change to a border, this example, use the alpha-lock, invert the selection.
https://i.imgur.com/y3iXPNY.mp4
notes:
The anti-alias toggle is in the tool-options. If you have closed the tool-options dock, then don't, reinstate it.
Don't know version of Gimp you are using? In the Help menu -> About It will tell you in big letters.