Pure-barcode mode can now deal with asymmetric borders instead of assuming it's pure generator output with equal borders

git-svn-id: https://zxing.googlecode.com/svn/trunk@1288 59b500cc-1b3d-0410-9834-0bbf25fbcc57

core/src/com/google/zxing/common/BitMatrix.java

@@ -145,6 +145,31 @@ public final class BitMatrix {
     return row;
   }
 
+  /**
+   * This is useful in detecting a corner of a 'pure' barcode.
+   * 
+   * @return {x,y} coordinate of top-left-most 1 bit, or null if it is all white
+   */
+  public int[] getTopLeftOnBit() {
+    int bitsOffset = 0;
+    while (bitsOffset < bits.length && bits[bitsOffset] == 0) {
+      bitsOffset++;
+    }
+    if (bitsOffset == bits.length) {
+      return null;
+    }
+    int y = bitsOffset / rowSize;
+    int x = (bitsOffset % rowSize) << 5;
+    
+    int theBits = bits[bitsOffset];
+    int bit = 0;
+    while ((theBits << (31-bit)) == 0) {
+      bit++;
+    }
+    x += bit;
+    return new int[] {x, y};
+  }
+
   /**
    * @return The width of the matrix
    */

core/src/com/google/zxing/datamatrix/DataMatrixReader.java

@@ -89,66 +89,67 @@ public final class DataMatrixReader implements Reader {
    * which contains only an unrotated, unskewed, image of a Data Matrix code, with some white border
    * around it. This is a specialized method that works exceptionally fast in this special
    * case.
+   *
+   * @see com.google.zxing.qrcode.QRCodeReader#extractPureBits(BitMatrix) 
    */
   private static BitMatrix extractPureBits(BitMatrix image) throws NotFoundException {
-    // Now need to determine module size in pixels
 
     int height = image.getHeight();
     int width = image.getWidth();
     int minDimension = Math.min(height, width);
 
-    // First, skip white border by tracking diagonally from the top left down and to the right:
-    int borderWidth = 0;
-    while (borderWidth < minDimension && !image.get(borderWidth, borderWidth)) {
-      borderWidth++;
-    }
-    if (borderWidth == minDimension) {
-      throw NotFoundException.getNotFoundInstance();
-    }
-
     // And then keep tracking across the top-left black module to determine module size
-    int moduleEnd = borderWidth + 1;
-    while (moduleEnd < width && image.get(moduleEnd, borderWidth)) {
-      moduleEnd++;
+    //int moduleEnd = borderWidth;
+    int[] leftTopBlack = image.getTopLeftOnBit();
+    if (leftTopBlack == null) {
+      throw NotFoundException.getNotFoundInstance();
     }
-    if (moduleEnd == width) {
+    int x = leftTopBlack[0];
+    int y = leftTopBlack[1];
+    while (x < minDimension && y < minDimension && image.get(x, y)) {
+      x++;
+    }
+    if (x == minDimension) {
       throw NotFoundException.getNotFoundInstance();
     }
 
-    int moduleSize = moduleEnd - borderWidth;
+    int moduleSize = x - leftTopBlack[0];
 
-    // And now find where the bottommost black module on the first column ends
-    int columnEndOfSymbol = height - 1;
-    while (columnEndOfSymbol >= 0 && !image.get(borderWidth, columnEndOfSymbol)) {
-    	columnEndOfSymbol--;
+    // And now find where the rightmost black module on the first row ends
+    int rowEndOfSymbol = width - 1;
+    while (rowEndOfSymbol >= 0 && !image.get(rowEndOfSymbol, y)) {
+      rowEndOfSymbol--;
     }
-    if (columnEndOfSymbol < 0) {
+    if (rowEndOfSymbol < 0) {
       throw NotFoundException.getNotFoundInstance();
     }
-    columnEndOfSymbol++;
+    rowEndOfSymbol++;
 
     // Make sure width of barcode is a multiple of module size
-    if ((columnEndOfSymbol - borderWidth) % moduleSize != 0) {
+    if ((rowEndOfSymbol - x) % moduleSize != 0) {
       throw NotFoundException.getNotFoundInstance();
     }
-    int dimension = (columnEndOfSymbol - borderWidth) / moduleSize;
+    int dimension = 2 + ((rowEndOfSymbol - x) / moduleSize);
 
+    y += moduleSize;
+    
     // Push in the "border" by half the module width so that we start
     // sampling in the middle of the module. Just in case the image is a
     // little off, this will help recover.
-    borderWidth += moduleSize >> 1;
+    x -= moduleSize >> 1;
+    y -= moduleSize >> 1;
 
-    int sampleDimension = borderWidth + (dimension - 1) * moduleSize;
-    if (sampleDimension >= width || sampleDimension >= height) {
+    if ((x + (dimension - 1) * moduleSize) >= width ||
+        (y + (dimension - 1) * moduleSize) >= height) {
       throw NotFoundException.getNotFoundInstance();
     }
 
     // Now just read off the bits
     BitMatrix bits = new BitMatrix(dimension);
     for (int i = 0; i < dimension; i++) {
-      int iOffset = borderWidth + i * moduleSize;
+      int iOffset = y + i * moduleSize;
       for (int j = 0; j < dimension; j++) {
-        if (image.get(borderWidth + j * moduleSize, iOffset)) {
+        if (image.get(x + j * moduleSize, iOffset)) {
           bits.set(j, i);
         }
       }

core/src/com/google/zxing/pdf417/PDF417Reader.java

@@ -29,6 +29,7 @@ import com.google.zxing.common.DecoderResult;
 import com.google.zxing.common.DetectorResult;
 import com.google.zxing.pdf417.decoder.Decoder;
 import com.google.zxing.pdf417.detector.Detector;
+import com.google.zxing.qrcode.QRCodeReader;
 
 import java.util.Hashtable;
 
@@ -59,7 +60,7 @@ public final class PDF417Reader implements Reader {
     DecoderResult decoderResult;
     ResultPoint[] points;
     if (hints != null && hints.containsKey(DecodeHintType.PURE_BARCODE)) {
-      BitMatrix bits = extractPureBits(image);
+      BitMatrix bits = QRCodeReader.extractPureBits(image.getBlackMatrix());
       decoderResult = decoder.decode(bits);
       points = NO_POINTS;
     } else {
@@ -75,75 +76,4 @@ public final class PDF417Reader implements Reader {
     // do nothing
   }
 
-  /**
-   * This method detects a barcode in a "pure" image -- that is, pure monochrome image
-   * which contains only an unrotated, unskewed, image of a barcode, with some white border
-   * around it. This is a specialized method that works exceptionally fast in this special
-   * case.
-   */
-  private static BitMatrix extractPureBits(BinaryBitmap image) throws NotFoundException {
-    // Now need to determine module size in pixels
-    BitMatrix matrix = image.getBlackMatrix();
-    int height = matrix.getHeight();
-    int width = matrix.getWidth();
-    int minDimension = Math.min(height, width);
-
-    // First, skip white border by tracking diagonally from the top left down and to the right:
-    int borderWidth = 0;
-    while (borderWidth < minDimension && !matrix.get(borderWidth, borderWidth)) {
-      borderWidth++;
-    }
-    if (borderWidth == minDimension) {
-      throw NotFoundException.getNotFoundInstance();
-    }
-
-    // And then keep tracking across the top-left black module to determine module size
-    int moduleEnd = borderWidth;
-    while (moduleEnd < minDimension && matrix.get(moduleEnd, moduleEnd)) {
-      moduleEnd++;
-    }
-    if (moduleEnd == minDimension) {
-      throw NotFoundException.getNotFoundInstance();
-    }
-
-    int moduleSize = moduleEnd - borderWidth;
-
-    // And now find where the rightmost black module on the first row ends
-    int rowEndOfSymbol = width - 1;
-    while (rowEndOfSymbol >= 0 && !matrix.get(rowEndOfSymbol, borderWidth)) {
-      rowEndOfSymbol--;
-    }
-    if (rowEndOfSymbol < 0) {
-      throw NotFoundException.getNotFoundInstance();
-    }
-    rowEndOfSymbol++;
-
-    // Make sure width of barcode is a multiple of module size
-    if ((rowEndOfSymbol - borderWidth) % moduleSize != 0) {
-      throw NotFoundException.getNotFoundInstance();
-    }
-    int dimension = (rowEndOfSymbol - borderWidth) / moduleSize;
-
-    // Push in the "border" by half the module width so that we start
-    // sampling in the middle of the module. Just in case the image is a
-    // little off, this will help recover.
-    borderWidth += moduleSize >> 1;
-
-    int sampleDimension = borderWidth + (dimension - 1) * moduleSize;
-    if (sampleDimension >= width || sampleDimension >= height) {
-      throw NotFoundException.getNotFoundInstance();
-    }
-
-    // Now just read off the bits
-    BitMatrix bits = new BitMatrix(dimension);
-    for (int y = 0; y < dimension; y++) {
-      int iOffset = borderWidth + y * moduleSize;
-      for (int x = 0; x < dimension; x++) {
-        if (matrix.get(borderWidth + x * moduleSize, iOffset)) {
-          bits.set(x, y);
-        }
-      }
-    }
-    return bits;
-  }
 }

core/src/com/google/zxing/qrcode/QRCodeReader.java

@@ -95,36 +95,33 @@ public class QRCodeReader implements Reader {
    * around it. This is a specialized method that works exceptionally fast in this special
    * case.
    */
-  private static BitMatrix extractPureBits(BitMatrix image) throws NotFoundException {
-    // Now need to determine module size in pixels
+  public static BitMatrix extractPureBits(BitMatrix image) throws NotFoundException {
 
     int height = image.getHeight();
     int width = image.getWidth();
     int minDimension = Math.min(height, width);
 
-    // First, skip white border by tracking diagonally from the top left down and to the right:
-    int borderWidth = 0;
-    while (borderWidth < minDimension && !image.get(borderWidth, borderWidth)) {
-      borderWidth++;
-    }
-    if (borderWidth == minDimension) {
-      throw NotFoundException.getNotFoundInstance();
-    }
-
     // And then keep tracking across the top-left black module to determine module size
-    int moduleEnd = borderWidth;
-    while (moduleEnd < minDimension && image.get(moduleEnd, moduleEnd)) {
-      moduleEnd++;
+    //int moduleEnd = borderWidth;
+    int[] leftTopBlack = image.getTopLeftOnBit();
+    if (leftTopBlack == null) {
+      throw NotFoundException.getNotFoundInstance();
     }
-    if (moduleEnd == minDimension) {
+    int x = leftTopBlack[0];
+    int y = leftTopBlack[1];
+    while (x < minDimension && y < minDimension && image.get(x, y)) {
+      x++;
+      y++;
+    }
+    if (x == minDimension || y == minDimension) {
       throw NotFoundException.getNotFoundInstance();
     }
 
-    int moduleSize = moduleEnd - borderWidth;
+    int moduleSize = x - leftTopBlack[0];
 
     // And now find where the rightmost black module on the first row ends
     int rowEndOfSymbol = width - 1;
-    while (rowEndOfSymbol >= 0 && !image.get(rowEndOfSymbol, borderWidth)) {
+    while (rowEndOfSymbol >= 0 && !image.get(rowEndOfSymbol, y)) {
       rowEndOfSymbol--;
     }
     if (rowEndOfSymbol < 0) {
@@ -133,27 +130,28 @@ public class QRCodeReader implements Reader {
     rowEndOfSymbol++;
 
     // Make sure width of barcode is a multiple of module size
-    if ((rowEndOfSymbol - borderWidth) % moduleSize != 0) {
+    if ((rowEndOfSymbol - x) % moduleSize != 0) {
       throw NotFoundException.getNotFoundInstance();
     }
-    int dimension = (rowEndOfSymbol - borderWidth) / moduleSize;
+    int dimension = 1 + ((rowEndOfSymbol - x) / moduleSize);
 
     // Push in the "border" by half the module width so that we start
     // sampling in the middle of the module. Just in case the image is a
     // little off, this will help recover.
-    borderWidth += moduleSize >> 1;
+    x -= moduleSize >> 1;
+    y -= moduleSize >> 1;
 
-    int sampleDimension = borderWidth + (dimension - 1) * moduleSize;
-    if (sampleDimension >= width || sampleDimension >= height) {
+    if ((x + (dimension - 1) * moduleSize) >= width ||
+        (y + (dimension - 1) * moduleSize) >= height) {
       throw NotFoundException.getNotFoundInstance();
     }
 
     // Now just read off the bits
     BitMatrix bits = new BitMatrix(dimension);
     for (int i = 0; i < dimension; i++) {
-      int iOffset = borderWidth + i * moduleSize;
+      int iOffset = y + i * moduleSize;
       for (int j = 0; j < dimension; j++) {
-        if (image.get(borderWidth + j * moduleSize, iOffset)) {
+        if (image.get(x + j * moduleSize, iOffset)) {
           bits.set(j, i);
         }
       }