What do the different variables mean in an .atlas file?

Question

Here is an example of a packed image in an .atlas file.

img5
  rotate: false
  xy: 1, 3
  size: 200,200
  orig: 200, 200
  offset: 0, 0
  index: -1

Answer 1

.atlas or .pack file is text file that describes all the images packed on the pages.

Binding the texture is relatively expensive, so it is ideal to store many smaller images on a larger image, bind the larger texture once, then draw portions of it many times.

When Packer keep smaller image into larger image, it keep some required information of smaller image into .atlas file. like name,is rotated for packing and more.

img5 - is the name of your small image
rotate: false - When you checked Allow Rotation in Texture Packer tool then image can be rotate for dense packing. This is the information about image rotation.

xy: 1, 3 - This is the position in large file from where image(img5) kept.
size: 200,200 - This is size of your small image(img5)
orig: 200, 200 - Origin of image
offset: 0, 0 The offset is whitespace that is removed for packing.
index: -1 If an image file name ends with underscore and then a number (eg xyz_3.png), the number is considered the "index" and is stored separately. -1 tell no indexing.