Merge pull request #42 from cozmo/fix-#41-crash-when-fewer-than-3-fin…

…der-patterns

Fix #41 crash when fewer than 3 finder patterns

dist/jsQR.js

@@ -9905,6 +9905,9 @@ function locate(matrix) {
             .filter(function (p, ii) { return i !== ii; })
             .map(function (p) { return ({ x: p.x, y: p.y, score: p.score + (Math.pow((p.size - point.size), 2)) / point.size, size: p.size }); })
             .sort(function (a, b) { return a.score - b.score; });
+        if (otherPoints.length < 2) {
+            return null;
+        }
         var score = point.score + otherPoints[0].score + otherPoints[1].score;
         return { points: [point].concat(otherPoints.slice(0, 2)), score: score };
     })

docs/jsQR.js

@@ -9905,6 +9905,9 @@ function locate(matrix) {
             .filter(function (p, ii) { return i !== ii; })
             .map(function (p) { return ({ x: p.x, y: p.y, score: p.score + (Math.pow((p.size - point.size), 2)) / point.size, size: p.size }); })
             .sort(function (a, b) { return a.score - b.score; });
+        if (otherPoints.length < 2) {
+            return null;
+        }
         var score = point.score + otherPoints[0].score + otherPoints[1].score;
         return { points: [point].concat(otherPoints.slice(0, 2)), score: score };
     })

src/locator/index.ts

@@ -341,6 +341,9 @@ export function locate(matrix: BitMatrix): QRLocation {
         .filter((p, ii) => i !== ii)
         .map(p => ({ x: p.x, y: p.y, score: p.score + ((p.size - point.size) ** 2) / point.size, size: p.size }))
         .sort((a, b) => a.score - b.score);
+      if (otherPoints.length < 2) {
+        return null;
+      }
       const score = point.score + otherPoints[0].score + otherPoints[1].score;
       return {points: [point].concat(otherPoints.slice(0, 2)), score};
     })

src/locator/test.ts

@@ -10,4 +10,9 @@ describe("locate", () => {
       expect(output).toEqual(t.location);
     });
   });
+
+  it("handles images with missing finder patterns", async () => {
+    const binarized = await loadBinarized("./src/locator/test-data/missing-finder-patterns.png");
+    expect(() => locate(binarized)).not.toThrow();
+  });
 });