The holes in a polygon selection can be used for
- polygon shape(polygon selection + rectangle)
- filters
- image stamp copy
- partial image saving (transparent holes)
Creating the hollow star in the example
- tap
- tap ☆
- drag to adjust the size/position
- Tap the rectangle icon to fill the star with a color. The color is editable.
- tap
- tap ☆
- drag to adjust the size/position to make the smaller ☆ inside the first ☆
- While the smaller ☆ is selected, tap 'selected polygon → Hole' of the second menu.
To create the hole of a filter, the steps are similar. Tapping 'grey level' filter instead of 'rectangle'.
How to revert a polygon hole selection to a non-hole polygon.
- Tap the large object.
- tap to switch to controlling-points(vertex) editing.
- Tap a controlling-point(vertex) of the hole.
- Tap again and the whole polygon of the hole is selected.
- Tap 'selected polygon → Hole' to revert to a normal polygon selection.