12-08-2018, 08:04 AM
Just in case tolworthy comes back.
There is a way to do this in Gimp.
If you have a black circle on a white background there are anti-aliasing pixels between the black and white. These are shades of grey. It is important to preserve these anti-aliasing pixels.
Summary of method:
1) Use Fuzzy select to select the white inside the circle.
2) Grow the selection by 1 or 2 pixels
3) Create a new transparent layer below your image.
4) On this new layer, bucket fill the selection with red
5) Select the top layer again
6) Colours > Colour to Alpha and accept the default white
Colour to Alpha preserves the anti-aliasing pixels.
There is a way to do this in Gimp.
If you have a black circle on a white background there are anti-aliasing pixels between the black and white. These are shades of grey. It is important to preserve these anti-aliasing pixels.
Summary of method:
1) Use Fuzzy select to select the white inside the circle.
2) Grow the selection by 1 or 2 pixels
3) Create a new transparent layer below your image.
4) On this new layer, bucket fill the selection with red
5) Select the top layer again
6) Colours > Colour to Alpha and accept the default white
Colour to Alpha preserves the anti-aliasing pixels.