When it comes to applications that use many images, it is important to reduce their loading time, especially when they are requested from a remote server.
Note
One strategy to reduce the loading time is to use an Atlas (also known as sprite). An Atlas groups all the application images into one big image, so it reduces the number of necessary requests to the operating system, or online requests.
Here is the image of the Atlas we use for invaders revenge:
Instead of requesting five images for the invaders revenge, we will just request the Atlas image. We will also need an associated json file that tells us the exact coordinates of each unit in the image. The good news is that we don't need to do this manually. Kivy provides a simple command to create both the Atlas image and the json file. Assuming that all the images are in a directory called img, we just need to open a terminal, go to the img directory (that contains the individual images), and run the...