334 CHAPTER 9: Android Graphic Design: Making Your UI Designs Visual
Figure 9-19 also shows the ImageButton1source.png layer being selected for the delete operation,
and that the selection is still “active” (that is, the ants are still marching). We need to get the
remaining (circular) galaxy part of the image onto its own layer with transparency, so I am going to
show you the work process to achieve that end result as well.
We are going to apply another clever technique as well as an often-used operation in digital image
editing called “inverting” the selection set. The principle behind this, which we have already seen
once in this book, way back in Chapter 3, is that it can often be easier to select what we don’t want
in the selection set, and then “invert” that selection to select what we do want in the selection (or as
the selection set).
What’s interesting in this case is that four different (separate) triangular selection areas are tuned
into one single circular selection area by using the Select ➤ Invert menu sequence, which is shown
in Figure 9-20. Notice that I have clicked on the eye icon next to the ImageButtonRing.png layer
to turn that layer visibility off, so that I can see more clearly what I am getting as a result in the
ImageButton1source.png layer. I have encircled the eye icon area in the Layers palette, showing that
the eye icon is no longer visible next to the ImageButtonRing.png layer.
Figure 9-19. Select source image layer and use the Delete key to remove the corners revealing the layer background