fix: "index out of bounds" on antialiasing check

src/Antialiasing.re

@@ -1,34 +1,38 @@
 open ImageIO;
 
 module MakeAntialiasing = (IO1: ImageIO.ImageIO, IO2: ImageIO.ImageIO) => {
-  let hasManySiblingsWithSameColor = (~x, ~y, ~width, ~height, ~readColor) => {
-    let x0 = max(x - 1, 0);
-    let y0 = max(y - 1, 0);
+  let hasManySiblingsWithSameColor = (~x, ~y, ~width, ~height, ~readColor) =>
+    if (x <= width - 1 && y <= height - 1) {
+      let x0 = max(x - 1, 0);
+      let y0 = max(y - 1, 0);
 
-    let x1 = min(x + 1, width - 1);
-    let y1 = min(y + 1, height - 1);
+      let x1 = min(x + 1, width - 1);
+      let y1 = min(y + 1, height - 1);
 
-    let zeroes = x == x0 || x == x1 || y == y0 || y == y1 ? ref(1) : ref(0);
+      let zeroes =
+        x == x0 || x == x1 || y == y0 || y == y1 ? ref(1) : ref(0);
 
-    let baseColor = readColor(~x, ~y);
+      let baseColor = readColor(~x, ~y);
 
-    // go through 8 adjacent pixels
-    for (adj_y in y0 to y1) {
-      for (adj_x in x0 to x1) {
-        /* This is the current pixel or we already have our result, do nothing */
-        if (x == adj_x && y == adj_y || zeroes^ >= 3) {
-          ();
-        } else {
-          let adjacentColor = readColor(~x=adj_x, ~y=adj_y);
-          if (Helpers.isSameColor(baseColor, adjacentColor)) {
-            zeroes := zeroes^ + 1;
+      // go through 8 adjacent pixels
+      for (adj_y in y0 to y1) {
+        for (adj_x in x0 to x1) {
+          /* This is the current pixel or we already have our result, do nothing */
+          if (x == adj_x && y == adj_y || zeroes^ >= 3) {
+            ();
+          } else {
+            let adjacentColor = readColor(~x=adj_x, ~y=adj_y);
+            if (Helpers.isSameColor(baseColor, adjacentColor)) {
+              zeroes := zeroes^ + 1;
+            };
           };
         };
       };
-    };
 
-    zeroes^ >= 3;
-  };
+      zeroes^ >= 3;
+    } else {
+      false;
+    };
 
   let detect = (~x, ~y, ~baseImg, ~compImg) => {
     let x0 = max(x - 1, 0);

test/PngTests.re

@@ -113,4 +113,25 @@ describe("Png comparing", ({test, _}) => {
     expect.int(diffPixels).toBe(diffPixelsMask);
     expect.float(diffPercentage).toBeCloseTo(diffPercentageMask);
   });
+
+  test("tests diffrent sized AA images", ({expect, _}) => {
+    let img1 =
+      PureC_IO_Bigarray.IO.loadImage("test/test-images/antialiasing-on.png");
+    let img2 =
+      PureC_IO_Bigarray.IO.loadImage(
+        "test/test-images/antialiasing-off-small.png",
+      );
+
+    let (_, diffPixels, diffPercentage) =
+      AADiff.compare(
+        img1,
+        img2,
+        ~outputDiffMask=true,
+        ~antialiasing=true,
+        (),
+      );
+
+    expect.int(diffPixels).toBe(417);
+    expect.float(diffPercentage).toBeCloseTo(1.04);
+  });
 });