330 CHAPTER 9: Android Graphic Design: Making Your UI Designs Visual
Figure 9-16. Using the File ➤ Open as Layers menu sequence to add the ImageButton ring decoration as a new layer
Notice the primary functional areas in GIMP: the layers and channels palettes at the top-left, the tool
icons palette to the right of that, the tool options palette underneath that, and the brushes palette
to the left of that. Note that these are floating tool palettes, so you can arrange GIMP 2.8 in any way
that might be best for the comfort of your particular work process.
The source image, which is the 500-pixel version of the Milky Way galaxy that I got from the NASA
web site, is shown on the right in the image editing area, and the layer it is on is shown selected in
blue on the left under the Layers palette, with its visibility (denoted using an eye icon) turned on.
Later, we will be using this eye icon to toggle layer visibility on and off, once we add some more
layers to your image composite, which we’ll do next.
Using GIMP for Compositing: Importing a Layer
The easiest way to add a new compositing layer in GIMP is to import an image which already has an
alpha channel in it, such as the ImageButtonRing.png PNG32 file shown at the top of Figure 9-14,
which is going to be the next layer up in your image composite, is to use the Open as Layers menu
sequence, which is shown in Figure 9-16.