First version of the iphone client that actually works, for at least a subset

[zxing.git] / cpp / core / src / common / GridSampler.cpp

diff --git a/cpp/core/src/common/GridSampler.cpp b/cpp/core/src/common/GridSampler.cpp
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+/*
+ *  GridSampler.cpp
+ *  zxing
+ *
+ *  Created by Christian Brunschen on 18/05/2008.
+ *  Copyright 2008 Google Inc. All rights reserved.
+ *
+ * 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.
+ */
+
+#include "GridSampler.h"
+#include "PerspectiveTransform.h"
+#include "ReaderException.h"
+#include <iostream>
+#include <sstream>
+
+namespace common {
+  GridSampler GridSampler::gridSampler;
+  
+  GridSampler::GridSampler() { }
+  
+  Ref<BitMatrix> GridSampler::sampleGrid(Ref<MonochromeBitmapSource> image,
+                                         int dimension,
+                                         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) {
+    Ref<PerspectiveTransform> transform
+    (PerspectiveTransform::quadrilateralToQuadrilateral
+     (p1ToX, p1ToY, p2ToX, p2ToY, p3ToX, p3ToY, p4ToX, p4ToY,
+      p1FromX, p1FromY, p2FromX, p2FromY, p3FromX, p3FromY, p4FromX, p4FromY));
+    
+    Ref<BitMatrix> bits(new BitMatrix(dimension));
+    valarray<float> points(dimension << 1);
+    for (int i = 0; i < dimension; i++) {
+      int max = points.size();
+      float iValue = (float) i + 0.5f;
+      for (int j = 0; j < max; j+= 2) {
+        points[j] = (float) (j >> 1) + 0.5f;
+        points[j + 1] = iValue;
+      }
+      transform->transformPoints(points);
+      checkAndNudgePoints(image, points);
+      for (int j = 0; j < max; j += 2) {
+        if (image->isBlack((int) points[j], (int) points[j + 1])) {
+          bits->set(i, j >> 1);
+        }
+      }
+    }
+    
+    return bits;
+  }
+  
+  void GridSampler::checkAndNudgePoints(Ref<MonochromeBitmapSource> image,
+                                        valarray<float> &points) {
+    int width = image->getWidth();
+    int height = image->getHeight();
+    // Check and nudge points from start until we see some that are OK:
+    bool nudged = true;
+    for (size_t offset = 0; offset < points.size() && nudged; offset += 2) {
+      int x = (int) points[offset];
+      int y = (int) points[offset + 1];
+      if (x < -1 || x > width || y < -1 || y > height) {
+        ostringstream s;
+        s << "Transformed point out of bounds at " << x << "," << y;
+        throw new ReaderException(s.str().c_str());
+      }
+      nudged = false;
+      if (x == -1) {
+        points[offset] = 0.0f;
+        nudged = true;
+      } else if (x == width) {
+        points[offset] = width - 1;
+        nudged = true;
+      }
+      if (y == -1) {
+        points[offset + 1] = 0.0f;
+        nudged = true;
+      } else if (y == height) {
+        points[offset + 1] = height - 1;
+        nudged = true;
+      }
+    }
+    // Check and nudge points from end:
+    nudged = true;
+    for (size_t offset = points.size() - 2; offset >= 0 && nudged; offset -= 2) {
+      int x = (int) points[offset];
+      int y = (int) points[offset + 1];
+      if (x < -1 || x > width || y < -1 || y > height) {
+        ostringstream s;
+        s << "Transformed point out of bounds at " << x << "," << y;
+        throw new ReaderException(s.str().c_str());
+      }
+      nudged = false;
+      if (x == -1) {
+        points[offset] = 0.0f;
+        nudged = true;
+      } else if (x == width) {
+        points[offset] = width - 1;
+        nudged = true;
+      }
+      if (y == -1) {
+        points[offset + 1] = 0.0f;
+        nudged = true;
+      } else if (y == height) {
+        points[offset + 1] = height - 1;
+        nudged = true;
+      }
+    }
+  }
+  
+  GridSampler &GridSampler::getInstance() {
+    return gridSampler;
+  }
+}