96 CHAPTER 3: An Introduction to the Android Application Development Platform
It is important to make sure that you scale down, or downsample, from the 200-pixel image each
time you scale. So do a 200 pixels scale down to 96 pixels, a 200 pixels scale down to 72 pixels,
and a 200 pixels scale down to 48 pixels. The reason for this is because the resulting quality will be
significantly higher this way than if you utilized a work process where you scale from 200 to 144, and
then 144 to 96, and then 96 to 72, and then 72 to 48.
This is because the more data you give the original Image Scaling Algorithm, the better job it will do;
the algorithm will have more source image data to work with to create a good downsample quality.
Theoretically, to get the absolute highest-quality result, you would want to design your source
image assets for your launcher icons to be 864 pixels! This is the resolution that Google actually
recommends in their graphic design guidelines, because each of the Android launcher icon
resolutions is an even downsample mathematically of that number. If you want to create an icon for
the Sony SmartWatch or SmartWatch 2, you will also want to create a 36-pixel LDPI
launcher_ic.png file, and put that into the /res/drawable-ldpi asset folder.
Saving Your GIMP Composite: Native .XCF Format
The next logical thing to do before you spend a lot of time creating all of these resolution density
icons is to save your work using GIMP’s native .XCF file format. This file format will not only save
your image data, but it will also save the structure of your image compositing “stack” or “pipeline”
shown on the left side of GIMP in Figures 3-10 and 3-14 (and which is obscured by menus in all of
the other GIMP screenshots, unfortunately).
Use the File ➤ Save As menu sequence shown in Figure 3-20 and save your GIMP project file on
your hard disk drive in your content production assets folder. Mine is called C:\Clients, and it has
sub-folders for each client.