Document spritesheet specification requirements

[elisechant]

It would be great if you could document information about spritesheet characteristics and specifications that this library requires.

I am looking at the mummy.png file and comparing it to my own spritesheet to find clues. But I am struggling to understand scaling and positioning of the spritesheet itself.

There are a number of configurations options for spritesheet generation that we have available to us, for example in Adobe Animate:

Currently I think it would be more intuitive if the input API was refactored to consume a spritesheet .png in addition to a coordinate mapping file which is usually .json instead of the rows, columns, width props.

In the interim, some basic documentation would be welcomed.

[mileung]

I made this library with Piskel in mind. I don't maintain the library anymore, but I accept PRs.

[elisechant]

@MiLeung ok. I found that Adobe Animate created sprite sheet images that were not cropped exactly to rows and columns. I created a PR to spell that requirement out to others that might come across the same issue in the future.