初始化fy

uni_modules/UniDevTools/node_modules/pngjs/lib/paeth-predictor.js

@@ -0,0 +1,17 @@
+'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;
+};