The Add to Selection command creates a selection in the image from the pixels of the active layer according to their transparency. Opaque areas are fully selected, transparent areas are unselected, and translucent areas are partially selected. This selection is added to an existing selection. The alpha channel itself is not changed.

The other commands in this group of operations are similar, except that instead of adding to the existing selection with the selection produced from the active layer, they either completely replace the selection with a selection produced from the alpha selection, subtract the alpha selection from the existing selection, or create a selection that is the intersection of the two.

10.45.2.  Example

Figure 10.113.  Applying “Add to Selection”

Non-transparent pixels of the active layer have been added to the existing selection.