Skip calls to antialiased when it is included (#160)

Author: mongoose700

index.js

@@ -72,8 +72,8 @@ export default function pixelmatch(img1, img2, output, width, height, options =
             // the color difference is above the threshold
             if (Math.abs(delta) > maxDelta) {
                 // check it's a real rendering difference or just anti-aliasing
-                const isAA = antialiased(img1, x, y, width, height, a32, b32) || antialiased(img2, x, y, width, height, b32, a32);
-                if (!includeAA && isAA) {
+                const isExcludedAA = !includeAA && (antialiased(img1, x, y, width, height, a32, b32) || antialiased(img2, x, y, width, height, b32, a32));
+                if (isExcludedAA) {
                     // one of the pixels is anti-aliasing; draw as yellow and do not count as difference
                     // note that we do not include such pixels in a mask
                     if (output && !diffMask) drawPixel(output, pos, aaR, aaG, aaB);