You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
17 lines
388 B
17 lines
388 B
'use strict';
|
|
|
|
module.exports = function paethPredictor(left, above, upLeft) {
|
|
|
|
var paeth = left + above - upLeft;
|
|
var pLeft = Math.abs(paeth - left);
|
|
var pAbove = Math.abs(paeth - above);
|
|
var pUpLeft = Math.abs(paeth - upLeft);
|
|
|
|
if (pLeft <= pAbove && pLeft <= pUpLeft) {
|
|
return left;
|
|
}
|
|
if (pAbove <= pUpLeft) {
|
|
return above;
|
|
}
|
|
return upLeft;
|
|
}; |