externalize zxing lib, fix gradle build

1 files changed, 585 insertions, 0 deletions

diff --git a/libraries/zxing/src/com/google/zxing/qrcode/detector/FinderPatternFinder.java b/libraries/zxing/src/com/google/zxing/qrcode/detector/FinderPatternFinder.java
new file mode 100644
index 000000000..01b3bde2a
--- /dev/null
+++ b/libraries/zxing/src/com/google/zxing/qrcode/detector/FinderPatternFinder.java
@@ -0,0 +1,585 @@
+/*

+ * 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.qrcode.detector;

+

+import com.google.zxing.DecodeHintType;

+import com.google.zxing.NotFoundException;

+import com.google.zxing.ResultPoint;

+import com.google.zxing.ResultPointCallback;

+import com.google.zxing.common.BitMatrix;

+import com.google.zxing.common.Collections;

+import com.google.zxing.common.Comparator;

+

+import java.util.Hashtable;

+import java.util.Vector;

+

+/**

+ * <p>This class attempts to find finder patterns in a QR Code. Finder patterns are the square

+ * markers at three corners of a QR Code.</p>

+ *

+ * <p>This class is thread-safe but not reentrant. Each thread must allocate its own object.

+ *

+ * @author Sean Owen

+ */

+public class FinderPatternFinder {

+

+  private static final int CENTER_QUORUM = 2;

+  protected static final int MIN_SKIP = 3; // 1 pixel/module times 3 modules/center

+  protected static final int MAX_MODULES = 57; // support up to version 10 for mobile clients

+  private static final int INTEGER_MATH_SHIFT = 8;

+

+  private final BitMatrix image;

+  private final Vector possibleCenters;

+  private boolean hasSkipped;

+  private final int[] crossCheckStateCount;

+  private final ResultPointCallback resultPointCallback;

+

+  /**

+   * <p>Creates a finder that will search the image for three finder patterns.</p>

+   *

+   * @param image image to search

+   */

+  public FinderPatternFinder(BitMatrix image) {

+    this(image, null);

+  }

+

+  public FinderPatternFinder(BitMatrix image, ResultPointCallback resultPointCallback) {

+    this.image = image;

+    this.possibleCenters = new Vector();

+    this.crossCheckStateCount = new int[5];

+    this.resultPointCallback = resultPointCallback;

+  }

+

+  protected BitMatrix getImage() {

+    return image;

+  }

+

+  protected Vector getPossibleCenters() {

+    return possibleCenters;

+  }

+

+  FinderPatternInfo find(Hashtable hints) throws NotFoundException {

+    boolean tryHarder = hints != null && hints.containsKey(DecodeHintType.TRY_HARDER);

+    int maxI = image.getHeight();

+    int maxJ = image.getWidth();

+    // We are looking for black/white/black/white/black modules in

+    // 1:1:3:1:1 ratio; this tracks the number of such modules seen so far

+

+    // Let's assume that the maximum version QR Code we support takes up 1/4 the height of the

+    // image, and then account for the center being 3 modules in size. This gives the smallest

+    // number of pixels the center could be, so skip this often. When trying harder, look for all

+    // QR versions regardless of how dense they are.

+    int iSkip = (3 * maxI) / (4 * MAX_MODULES);

+    if (iSkip < MIN_SKIP || tryHarder) {

+      iSkip = MIN_SKIP;

+    }

+

+    boolean done = false;

+    int[] stateCount = new int[5];

+    for (int i = iSkip - 1; i < maxI && !done; i += iSkip) {

+      // Get a row of black/white values

+      stateCount[0] = 0;

+      stateCount[1] = 0;

+      stateCount[2] = 0;

+      stateCount[3] = 0;

+      stateCount[4] = 0;

+      int currentState = 0;

+      for (int j = 0; j < maxJ; j++) {

+        if (image.get(j, i)) {

+          // Black pixel

+          if ((currentState & 1) == 1) { // Counting white pixels

+            currentState++;

+          }

+          stateCount[currentState]++;

+        } else { // White pixel

+          if ((currentState & 1) == 0) { // Counting black pixels

+            if (currentState == 4) { // A winner?

+              if (foundPatternCross(stateCount)) { // Yes

+                boolean confirmed = handlePossibleCenter(stateCount, i, j);

+                if (confirmed) {

+                  // Start examining every other line. Checking each line turned out to be too

+                  // expensive and didn't improve performance.

+                  iSkip = 2;

+                  if (hasSkipped) {

+                    done = haveMultiplyConfirmedCenters();

+                  } else {

+                    int rowSkip = findRowSkip();

+                    if (rowSkip > stateCount[2]) {

+                      // Skip rows between row of lower confirmed center

+                      // and top of presumed third confirmed center

+                      // but back up a bit to get a full chance of detecting

+                      // it, entire width of center of finder pattern

+

+                      // Skip by rowSkip, but back off by stateCount[2] (size of last center

+                      // of pattern we saw) to be conservative, and also back off by iSkip which

+                      // is about to be re-added

+                      i += rowSkip - stateCount[2] - iSkip;

+                      j = maxJ - 1;

+                    }

+                  }

+                } else {

+                  stateCount[0] = stateCount[2];

+                  stateCount[1] = stateCount[3];

+                  stateCount[2] = stateCount[4];

+                  stateCount[3] = 1;

+                  stateCount[4] = 0;

+                  currentState = 3;

+                  continue;

+                }

+                // Clear state to start looking again

+                currentState = 0;

+                stateCount[0] = 0;

+                stateCount[1] = 0;

+                stateCount[2] = 0;

+                stateCount[3] = 0;

+                stateCount[4] = 0;

+              } else { // No, shift counts back by two

+                stateCount[0] = stateCount[2];

+                stateCount[1] = stateCount[3];

+                stateCount[2] = stateCount[4];

+                stateCount[3] = 1;

+                stateCount[4] = 0;

+                currentState = 3;

+              }

+            } else {

+              stateCount[++currentState]++;

+            }

+          } else { // Counting white pixels

+            stateCount[currentState]++;

+          }

+        }

+      }

+      if (foundPatternCross(stateCount)) {

+        boolean confirmed = handlePossibleCenter(stateCount, i, maxJ);

+        if (confirmed) {

+          iSkip = stateCount[0];

+          if (hasSkipped) {

+            // Found a third one

+            done = haveMultiplyConfirmedCenters();

+          }

+        }

+      }

+    }

+

+    FinderPattern[] patternInfo = selectBestPatterns();

+    ResultPoint.orderBestPatterns(patternInfo);

+

+    return new FinderPatternInfo(patternInfo);

+  }

+

+  /**

+   * Given a count of black/white/black/white/black pixels just seen and an end position,

+   * figures the location of the center of this run.

+   */

+  private static float centerFromEnd(int[] stateCount, int end) {

+    return (float) (end - stateCount[4] - stateCount[3]) - stateCount[2] / 2.0f;

+  }

+

+  /**

+   * @param stateCount count of black/white/black/white/black pixels just read

+   * @return true iff the proportions of the counts is close enough to the 1/1/3/1/1 ratios

+   *         used by finder patterns to be considered a match

+   */

+  protected static boolean foundPatternCross(int[] stateCount) {

+    int totalModuleSize = 0;

+    for (int i = 0; i < 5; i++) {

+      int count = stateCount[i];

+      if (count == 0) {

+        return false;

+      }

+      totalModuleSize += count;

+    }

+    if (totalModuleSize < 7) {

+      return false;

+    }

+    int moduleSize = (totalModuleSize << INTEGER_MATH_SHIFT) / 7;

+    int maxVariance = moduleSize / 2;

+    // Allow less than 50% variance from 1-1-3-1-1 proportions

+    return Math.abs(moduleSize - (stateCount[0] << INTEGER_MATH_SHIFT)) < maxVariance &&

+        Math.abs(moduleSize - (stateCount[1] << INTEGER_MATH_SHIFT)) < maxVariance &&

+        Math.abs(3 * moduleSize - (stateCount[2] << INTEGER_MATH_SHIFT)) < 3 * maxVariance &&

+        Math.abs(moduleSize - (stateCount[3] << INTEGER_MATH_SHIFT)) < maxVariance &&

+        Math.abs(moduleSize - (stateCount[4] << INTEGER_MATH_SHIFT)) < maxVariance;

+  }

+

+  private int[] getCrossCheckStateCount() {

+    crossCheckStateCount[0] = 0;

+    crossCheckStateCount[1] = 0;

+    crossCheckStateCount[2] = 0;

+    crossCheckStateCount[3] = 0;

+    crossCheckStateCount[4] = 0;

+    return crossCheckStateCount;

+  }

+

+  /**

+   * <p>After a horizontal scan finds a potential finder pattern, this method

+   * "cross-checks" by scanning down vertically through the center of the possible

+   * finder pattern to see if the same proportion is detected.</p>

+   *

+   * @param startI row where a finder pattern was detected

+   * @param centerJ center of the section that appears to cross a finder pattern

+   * @param maxCount maximum reasonable number of modules that should be

+   * observed in any reading state, based on the results of the horizontal scan

+   * @return vertical center of finder pattern, or {@link Float#NaN} if not found

+   */

+  private float crossCheckVertical(int startI, int centerJ, int maxCount,

+      int originalStateCountTotal) {

+    BitMatrix image = this.image;

+

+    int maxI = image.getHeight();

+    int[] stateCount = getCrossCheckStateCount();

+

+    // Start counting up from center

+    int i = startI;

+    while (i >= 0 && image.get(centerJ, i)) {

+      stateCount[2]++;

+      i--;

+    }

+    if (i < 0) {

+      return Float.NaN;

+    }

+    while (i >= 0 && !image.get(centerJ, i) && stateCount[1] <= maxCount) {

+      stateCount[1]++;

+      i--;

+    }

+    // If already too many modules in this state or ran off the edge:

+    if (i < 0 || stateCount[1] > maxCount) {

+      return Float.NaN;

+    }

+    while (i >= 0 && image.get(centerJ, i) && stateCount[0] <= maxCount) {

+      stateCount[0]++;

+      i--;

+    }

+    if (stateCount[0] > maxCount) {

+      return Float.NaN;

+    }

+

+    // Now also count down from center

+    i = startI + 1;

+    while (i < maxI && image.get(centerJ, i)) {

+      stateCount[2]++;

+      i++;

+    }

+    if (i == maxI) {

+      return Float.NaN;

+    }

+    while (i < maxI && !image.get(centerJ, i) && stateCount[3] < maxCount) {

+      stateCount[3]++;

+      i++;

+    }

+    if (i == maxI || stateCount[3] >= maxCount) {

+      return Float.NaN;

+    }

+    while (i < maxI && image.get(centerJ, i) && stateCount[4] < maxCount) {

+      stateCount[4]++;

+      i++;

+    }

+    if (stateCount[4] >= maxCount) {

+      return Float.NaN;

+    }

+

+    // If we found a finder-pattern-like section, but its size is more than 40% different than

+    // the original, assume it's a false positive

+    int stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2] + stateCount[3] +

+        stateCount[4];

+    if (5 * Math.abs(stateCountTotal - originalStateCountTotal) >= 2 * originalStateCountTotal) {

+      return Float.NaN;

+    }

+

+    return foundPatternCross(stateCount) ? centerFromEnd(stateCount, i) : Float.NaN;

+  }

+

+  /**

+   * <p>Like {@link #crossCheckVertical(int, int, int, int)}, and in fact is basically identical,

+   * except it reads horizontally instead of vertically. This is used to cross-cross

+   * check a vertical cross check and locate the real center of the alignment pattern.</p>

+   */

+  private float crossCheckHorizontal(int startJ, int centerI, int maxCount,

+      int originalStateCountTotal) {

+    BitMatrix image = this.image;

+

+    int maxJ = image.getWidth();

+    int[] stateCount = getCrossCheckStateCount();

+

+    int j = startJ;

+    while (j >= 0 && image.get(j, centerI)) {

+      stateCount[2]++;

+      j--;

+    }

+    if (j < 0) {

+      return Float.NaN;

+    }

+    while (j >= 0 && !image.get(j, centerI) && stateCount[1] <= maxCount) {

+      stateCount[1]++;

+      j--;

+    }

+    if (j < 0 || stateCount[1] > maxCount) {

+      return Float.NaN;

+    }

+    while (j >= 0 && image.get(j, centerI) && stateCount[0] <= maxCount) {

+      stateCount[0]++;

+      j--;

+    }

+    if (stateCount[0] > maxCount) {

+      return Float.NaN;

+    }

+

+    j = startJ + 1;

+    while (j < maxJ && image.get(j, centerI)) {

+      stateCount[2]++;

+      j++;

+    }

+    if (j == maxJ) {

+      return Float.NaN;

+    }

+    while (j < maxJ && !image.get(j, centerI) && stateCount[3] < maxCount) {

+      stateCount[3]++;

+      j++;

+    }

+    if (j == maxJ || stateCount[3] >= maxCount) {

+      return Float.NaN;

+    }

+    while (j < maxJ && image.get(j, centerI) && stateCount[4] < maxCount) {

+      stateCount[4]++;

+      j++;

+    }

+    if (stateCount[4] >= maxCount) {

+      return Float.NaN;

+    }

+

+    // If we found a finder-pattern-like section, but its size is significantly different than

+    // the original, assume it's a false positive

+    int stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2] + stateCount[3] +

+        stateCount[4];

+    if (5 * Math.abs(stateCountTotal - originalStateCountTotal) >= originalStateCountTotal) {

+      return Float.NaN;

+    }

+

+    return foundPatternCross(stateCount) ? centerFromEnd(stateCount, j) : Float.NaN;

+  }

+

+  /**

+   * <p>This is called when a horizontal scan finds a possible alignment pattern. It will

+   * cross check with a vertical scan, and if successful, will, ah, cross-cross-check

+   * with another horizontal scan. This is needed primarily to locate the real horizontal

+   * center of the pattern in cases of extreme skew.</p>

+   *

+   * <p>If that succeeds the finder pattern location is added to a list that tracks

+   * the number of times each location has been nearly-matched as a finder pattern.

+   * Each additional find is more evidence that the location is in fact a finder

+   * pattern center

+   *

+   * @param stateCount reading state module counts from horizontal scan

+   * @param i row where finder pattern may be found

+   * @param j end of possible finder pattern in row

+   * @return true if a finder pattern candidate was found this time

+   */

+  protected boolean handlePossibleCenter(int[] stateCount, int i, int j) {

+    int stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2] + stateCount[3] +

+        stateCount[4];

+    float centerJ = centerFromEnd(stateCount, j);

+    float centerI = crossCheckVertical(i, (int) centerJ, stateCount[2], stateCountTotal);

+    if (!Float.isNaN(centerI)) {

+      // Re-cross check

+      centerJ = crossCheckHorizontal((int) centerJ, (int) centerI, stateCount[2], stateCountTotal);

+      if (!Float.isNaN(centerJ)) {

+        float estimatedModuleSize = (float) stateCountTotal / 7.0f;

+        boolean found = false;

+        int max = possibleCenters.size();

+        for (int index = 0; index < max; index++) {

+          FinderPattern center = (FinderPattern) possibleCenters.elementAt(index);

+          // Look for about the same center and module size:

+          if (center.aboutEquals(estimatedModuleSize, centerI, centerJ)) {

+            center.incrementCount();

+            found = true;

+            break;

+          }

+        }

+        if (!found) {

+          ResultPoint point = new FinderPattern(centerJ, centerI, estimatedModuleSize);

+          possibleCenters.addElement(point);

+          if (resultPointCallback != null) {

+            resultPointCallback.foundPossibleResultPoint(point);

+          }

+        }

+        return true;

+      }

+    }

+    return false;

+  }

+

+  /**

+   * @return number of rows we could safely skip during scanning, based on the first

+   *         two finder patterns that have been located. In some cases their position will

+   *         allow us to infer that the third pattern must lie below a certain point farther

+   *         down in the image.

+   */

+  private int findRowSkip() {

+    int max = possibleCenters.size();

+    if (max <= 1) {

+      return 0;

+    }

+    FinderPattern firstConfirmedCenter = null;

+    for (int i = 0; i < max; i++) {

+      FinderPattern center = (FinderPattern) possibleCenters.elementAt(i);

+      if (center.getCount() >= CENTER_QUORUM) {

+        if (firstConfirmedCenter == null) {

+          firstConfirmedCenter = center;

+        } else {

+          // We have two confirmed centers

+          // How far down can we skip before resuming looking for the next

+          // pattern? In the worst case, only the difference between the

+          // difference in the x / y coordinates of the two centers.

+          // This is the case where you find top left last.

+          hasSkipped = true;

+          return (int) (Math.abs(firstConfirmedCenter.getX() - center.getX()) -

+              Math.abs(firstConfirmedCenter.getY() - center.getY())) / 2;

+        }

+      }

+    }

+    return 0;

+  }

+

+  /**

+   * @return true iff we have found at least 3 finder patterns that have been detected

+   *         at least {@link #CENTER_QUORUM} times each, and, the estimated module size of the

+   *         candidates is "pretty similar"

+   */

+  private boolean haveMultiplyConfirmedCenters() {

+    int confirmedCount = 0;

+    float totalModuleSize = 0.0f;

+    int max = possibleCenters.size();

+    for (int i = 0; i < max; i++) {

+      FinderPattern pattern = (FinderPattern) possibleCenters.elementAt(i);

+      if (pattern.getCount() >= CENTER_QUORUM) {

+        confirmedCount++;

+        totalModuleSize += pattern.getEstimatedModuleSize();

+      }

+    }

+    if (confirmedCount < 3) {

+      return false;

+    }

+    // OK, we have at least 3 confirmed centers, but, it's possible that one is a "false positive"

+    // and that we need to keep looking. We detect this by asking if the estimated module sizes

+    // vary too much. We arbitrarily say that when the total deviation from average exceeds

+    // 5% of the total module size estimates, it's too much.

+    float average = totalModuleSize / (float) max;

+    float totalDeviation = 0.0f;

+    for (int i = 0; i < max; i++) {

+      FinderPattern pattern = (FinderPattern) possibleCenters.elementAt(i);

+      totalDeviation += Math.abs(pattern.getEstimatedModuleSize() - average);

+    }

+    return totalDeviation <= 0.05f * totalModuleSize;

+  }

+

+  /**

+   * @return the 3 best {@link FinderPattern}s from our list of candidates. The "best" are

+   *         those that have been detected at least {@link #CENTER_QUORUM} times, and whose module

+   *         size differs from the average among those patterns the least

+   * @throws NotFoundException if 3 such finder patterns do not exist

+   */

+  private FinderPattern[] selectBestPatterns() throws NotFoundException {

+

+    int startSize = possibleCenters.size();

+    if (startSize < 3) {

+      // Couldn't find enough finder patterns

+      throw NotFoundException.getNotFoundInstance();

+    }

+

+    // Filter outlier possibilities whose module size is too different

+    if (startSize > 3) {

+      // But we can only afford to do so if we have at least 4 possibilities to choose from

+      float totalModuleSize = 0.0f;

+      float square = 0.0f;

+      for (int i = 0; i < startSize; i++) {

+        float size = ((FinderPattern) possibleCenters.elementAt(i)).getEstimatedModuleSize();

+        totalModuleSize += size;

+        square += size * size;

+      }

+      float average = totalModuleSize / (float) startSize;

+      float stdDev = (float) Math.sqrt(square / startSize - average * average);

+

+      Collections.insertionSort(possibleCenters, new FurthestFromAverageComparator(average));

+

+      float limit = Math.max(0.2f * average, stdDev);

+

+      for (int i = 0; i < possibleCenters.size() && possibleCenters.size() > 3; i++) {

+        FinderPattern pattern = (FinderPattern) possibleCenters.elementAt(i);

+        if (Math.abs(pattern.getEstimatedModuleSize() - average) > limit) {

+          possibleCenters.removeElementAt(i);

+          i--;

+        }

+      }

+    }

+

+    if (possibleCenters.size() > 3) {

+      // Throw away all but those first size candidate points we found.

+

+      float totalModuleSize = 0.0f;

+      for (int i = 0; i < possibleCenters.size(); i++) {

+        totalModuleSize += ((FinderPattern) possibleCenters.elementAt(i)).getEstimatedModuleSize();

+      }

+

+      float average = totalModuleSize / (float) possibleCenters.size();

+

+      Collections.insertionSort(possibleCenters, new CenterComparator(average));

+

+      possibleCenters.setSize(3);

+    }

+

+    return new FinderPattern[]{

+        (FinderPattern) possibleCenters.elementAt(0),

+        (FinderPattern) possibleCenters.elementAt(1),

+        (FinderPattern) possibleCenters.elementAt(2)

+    };

+  }

+

+  /**

+   * <p>Orders by furthest from average</p>

+   */

+  private static class FurthestFromAverageComparator implements Comparator {

+    private final float average;

+    private FurthestFromAverageComparator(float f) {

+      average = f;

+    }

+    public int compare(Object center1, Object center2) {

+      float dA = Math.abs(((FinderPattern) center2).getEstimatedModuleSize() - average);

+      float dB = Math.abs(((FinderPattern) center1).getEstimatedModuleSize() - average);

+      return dA < dB ? -1 : dA == dB ? 0 : 1;

+    }

+  }

+

+  /**

+   * <p>Orders by {@link FinderPattern#getCount()}, descending.</p>

+   */

+  private static class CenterComparator implements Comparator {

+    private final float average;

+    private CenterComparator(float f) {

+      average = f;

+    }

+    public int compare(Object center1, Object center2) {

+      if (((FinderPattern) center2).getCount() == ((FinderPattern) center1).getCount()) {

+        float dA = Math.abs(((FinderPattern) center2).getEstimatedModuleSize() - average);

+        float dB = Math.abs(((FinderPattern) center1).getEstimatedModuleSize() - average);

+        return dA < dB ? 1 : dA == dB ? 0 : -1;

+      } else {

+        return ((FinderPattern) center2).getCount() - ((FinderPattern) center1).getCount();

+      }

+    }

+  }

+

+}