https://en.wikipedia.org/wiki/Affine_transformation
Affine transformation - Wikipedia
affine transformationwikipedia
https://www.bejson.com/php_manual/function.imageaffinematrixconcat.html
Concatenate two affine transformation matrices-BeJSON.com
An affine transformation matrix (an array with keys 0 to 5 and float values).
affine transformationconcatenatetwomatrices