Why provide multiple drawables for various densities?

Question

My app supports various screen densities from ldpi to xhdpi. It contains some drawables (images) that need to be displayed properly on all densities. I\'m wondering how many

Answer 1

There are several reasons to used prescaled drawables:

1. Scaling down to lower resolutions takes resources (CPU time, memory and it drains your battery faster), especially if you have a lot of images this might be undesired.

2. Scaling down a large image might result in worse quality than using a 'pre-tuned' smaller image. Especially if your images are based on a vector original. Or they contain very fine lines or details, which will get lost when due to the scaling.
   For example:
   becomes
   See here for the source of these images and more information on scaling artifacts.

3. On lower resolutions the image pixels are larger (or the image gets smaller), so it might be required to remove certain aspects of the image to keep it clear/understandable.