1 files changed, 86 insertions, 0 deletions
diff --git a/libraries/zxing/src/com/google/zxing/common/DefaultGridSampler.java b/libraries/zxing/src/com/google/zxing/common/DefaultGridSampler.java
new file mode 100644
index 000000000..74c9e7c6b
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+++ b/libraries/zxing/src/com/google/zxing/common/DefaultGridSampler.java
@@ -0,0 +1,86 @@
+/*
+ * Copyright 2007 ZXing authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.zxing.common;
+
+import com.google.zxing.NotFoundException;
+
+/**
+ * @author Sean Owen
+ */
+public final class DefaultGridSampler extends GridSampler {
+
+  public BitMatrix sampleGrid(BitMatrix image,
+                              int dimensionX,
+                              int dimensionY,
+                              float p1ToX, float p1ToY,
+                              float p2ToX, float p2ToY,
+                              float p3ToX, float p3ToY,
+                              float p4ToX, float p4ToY,
+                              float p1FromX, float p1FromY,
+                              float p2FromX, float p2FromY,
+                              float p3FromX, float p3FromY,
+                              float p4FromX, float p4FromY) throws NotFoundException {
+
+    PerspectiveTransform transform = PerspectiveTransform.quadrilateralToQuadrilateral(
+        p1ToX, p1ToY, p2ToX, p2ToY, p3ToX, p3ToY, p4ToX, p4ToY,
+        p1FromX, p1FromY, p2FromX, p2FromY, p3FromX, p3FromY, p4FromX, p4FromY);
+
+    return sampleGrid(image, dimensionX, dimensionY, transform);
+  }
+
+  public BitMatrix sampleGrid(BitMatrix image,
+                              int dimensionX,
+                              int dimensionY,
+                              PerspectiveTransform transform) throws NotFoundException {
+    if (dimensionX <= 0 || dimensionY <= 0) {
+      throw NotFoundException.getNotFoundInstance();      
+    }
+    BitMatrix bits = new BitMatrix(dimensionX, dimensionY);
+    float[] points = new float[dimensionX << 1];
+    for (int y = 0; y < dimensionY; y++) {
+      int max = points.length;
+      float iValue = (float) y + 0.5f;
+      for (int x = 0; x < max; x += 2) {
+        points[x] = (float) (x >> 1) + 0.5f;
+        points[x + 1] = iValue;
+      }
+      transform.transformPoints(points);
+      // Quick check to see if points transformed to something inside the image;
+      // sufficient to check the endpoints
+      checkAndNudgePoints(image, points);
+      try {
+        for (int x = 0; x < max; x += 2) {
+          if (image.get((int) points[x], (int) points[x + 1])) {
+            // Black(-ish) pixel
+            bits.set(x >> 1, y);
+          }
+        }
+      } catch (ArrayIndexOutOfBoundsException aioobe) {
+        // This feels wrong, but, sometimes if the finder patterns are misidentified, the resulting
+        // transform gets "twisted" such that it maps a straight line of points to a set of points
+        // whose endpoints are in bounds, but others are not. There is probably some mathematical
+        // way to detect this about the transformation that I don't know yet.
+        // This results in an ugly runtime exception despite our clever checks above -- can't have
+        // that. We could check each point's coordinates but that feels duplicative. We settle for
+        // catching and wrapping ArrayIndexOutOfBoundsException.
+        throw NotFoundException.getNotFoundInstance();
+      }
+    }
+    return bits;
+  }
+
+}