Support inverted QR codes (#67)

src/BitMatrix.ts

@@ -31,4 +31,8 @@ export class BitMatrix {
       }
     }
   }
+
+  public getInverted() {
+    return new BitMatrix(this.data.map(d => d === 0 ? 1 : 0), this.width);
+  }
 }

src/index.ts

@@ -23,13 +23,12 @@ export interface QRCode {
   };
 }
 
-function jsQR(data: Uint8ClampedArray, width: number, height: number): QRCode | null {
-  const binarized = binarize(data, width, height);
-  const location = locate(binarized);
+function scan(matrix: BitMatrix): QRCode | null {
+  const location = locate(matrix);
   if (!location) {
     return null;
   }
-  const extracted = extract(binarized, location);
+  const extracted = extract(matrix, location);
   const decoded = decode(extracted.matrix);
 
   if (!decoded) {
@@ -55,5 +54,14 @@ function jsQR(data: Uint8ClampedArray, width: number, height: number): QRCode |
   };
 }
 
+function jsQR(data: Uint8ClampedArray, width: number, height: number): QRCode | null {
+  const binarized = binarize(data, width, height);
+  let result = scan(binarized);
+  if (!result) {
+    result = scan(binarized.getInverted());
+  }
+  return result;
+}
+
 (jsQR as any).default = jsQR;
 export default jsQR;

tests/end-to-end/152/output.json

@@ -245,4 +245,4 @@
       "y": 307
     }
   }
-}
+}

tests/end-to-end/issue-59-inverted/output.json

@@ -0,0 +1,91 @@
+{
+  "binaryData": [
+    104,
+    116,
+    116,
+    112,
+    58,
+    47,
+    47,
+    119,
+    119,
+    119,
+    46,
+    113,
+    114,
+    115,
+    116,
+    117,
+    102,
+    102,
+    46,
+    99,
+    111,
+    109
+  ],
+  "data": "http://www.qrstuff.com",
+  "chunks": [
+    {
+      "type": "byte",
+      "bytes": [
+        104,
+        116,
+        116,
+        112,
+        58,
+        47,
+        47,
+        119,
+        119,
+        119,
+        46,
+        113,
+        114,
+        115,
+        116,
+        117,
+        102,
+        102,
+        46,
+        99,
+        111,
+        109
+      ],
+      "text": "http://www.qrstuff.com"
+    }
+  ],
+  "location": {
+    "topRightCorner": {
+      "x": 159.66666666666669,
+      "y": 20.333333333333332
+    },
+    "topLeftCorner": {
+      "x": 26.085501858736055,
+      "y": 20.08550185873606
+    },
+    "bottomRightCorner": {
+      "x": 158.18365235385414,
+      "y": 152.18365235385411
+    },
+    "bottomLeftCorner": {
+      "x": 26.333333333333332,
+      "y": 153.66666666666666
+    },
+    "topRightFinderPattern": {
+      "x": 141,
+      "y": 39
+    },
+    "topLeftFinderPattern": {
+      "x": 45,
+      "y": 39
+    },
+    "bottomLeftFinderPattern": {
+      "x": 45,
+      "y": 135
+    },
+    "bottomRightAlignmentPattern": {
+      "x": 124.5,
+      "y": 118.5
+    }
+  }
+}

tests/end-to-end/issue-59/output.json

@@ -0,0 +1,91 @@
+{
+  "binaryData": [
+    104,
+    116,
+    116,
+    112,
+    58,
+    47,
+    47,
+    119,
+    119,
+    119,
+    46,
+    113,
+    114,
+    115,
+    116,
+    117,
+    102,
+    102,
+    46,
+    99,
+    111,
+    109
+  ],
+  "data": "http://www.qrstuff.com",
+  "chunks": [
+    {
+      "type": "byte",
+      "bytes": [
+        104,
+        116,
+        116,
+        112,
+        58,
+        47,
+        47,
+        119,
+        119,
+        119,
+        46,
+        113,
+        114,
+        115,
+        116,
+        117,
+        102,
+        102,
+        46,
+        99,
+        111,
+        109
+      ],
+      "text": "http://www.qrstuff.com"
+    }
+  ],
+  "location": {
+    "topRightCorner": {
+      "x": 153.66666666666666,
+      "y": 20.333333333333332
+    },
+    "topLeftCorner": {
+      "x": 20.08550185873606,
+      "y": 20.08550185873606
+    },
+    "bottomRightCorner": {
+      "x": 152.18365235385411,
+      "y": 152.18365235385411
+    },
+    "bottomLeftCorner": {
+      "x": 20.333333333333332,
+      "y": 153.66666666666666
+    },
+    "topRightFinderPattern": {
+      "x": 135,
+      "y": 39
+    },
+    "topLeftFinderPattern": {
+      "x": 39,
+      "y": 39
+    },
+    "bottomLeftFinderPattern": {
+      "x": 39,
+      "y": 135
+    },
+    "bottomRightAlignmentPattern": {
+      "x": 118.5,
+      "y": 118.5
+    }
+  }
+}

tests/end-to-end/report.json

@@ -1,7 +1,7 @@
 {
   "counts": {
     "failed": 47,
-    "successful": 204
+    "successful": 206
   },
   "tests": {
     "0": true,
@@ -219,6 +219,8 @@
     "issue-34-regression": true,
     "issue-54-1": false,
     "issue-54-2": false,
+    "issue-59": true,
+    "issue-59-inverted": true,
     "japan-visa": false,
     "japanese-jean-ad": false,
     "kanji": true,