PDF417 detector: try 90 and 270 rotations also (#1333)

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

@@ -35,10 +35,10 @@ import java.util.Arrays;
  */
 public final class BitMatrix implements Cloneable {
 
-  private final int width;
-  private final int height;
-  private final int rowSize;
-  private final int[] bits;
+  private int width;
+  private int height;
+  private int rowSize;
+  private int[] bits;
 
   /**
    * Creates an empty square {@code BitMatrix}.
@@ -294,6 +294,32 @@ public final class BitMatrix implements Cloneable {
     }
   }
 
+  /**
+   * Modifies this {@code BitMatrix} to represent the same but rotated 90 degrees counterclockwise
+   */
+  public void rotate90() {
+    int newWidth = height;
+    int newHeight = width;
+    int newRowSize = (newWidth + 31) / 32;
+    int[] newBits = new int[newRowSize * newHeight];
+
+    for (int y = 0; y < height; y++) {
+      for (int x = 0; x < width; x++) {
+        int offset = y * rowSize + (x / 32);
+        if (((bits[offset] >>> (x & 0x1f)) & 1) != 0) {
+          int newY = newHeight - 1 - x;
+          int newX = y;
+          int newOffset = newY * newRowSize + (newX / 32);
+          newBits[newOffset] |= 1 << (newX & 0x1f);
+        }
+      }
+    }
+    width = newWidth;
+    height = newHeight;
+    rowSize = newRowSize;
+    bits = newBits;
+  }
+
   /**
    * This is useful in detecting the enclosing rectangle of a 'pure' barcode.
    *

core/src/main/java/com/google/zxing/pdf417/detector/Detector.java

@@ -61,7 +61,7 @@ public final class Detector {
   }
 
   /**
-   * <p>Detects a PDF417 Code in an image. Only checks 0 and 180 degree rotations.</p>
+   * <p>Detects a PDF417 Code in an image. Checks 0, 90, 180, and 270 degree rotations.</p>
    *
    * @param image barcode image to decode
    * @param hints optional hints to detector
@@ -79,9 +79,14 @@ public final class Detector {
     BitMatrix bitMatrix = image.getBlackMatrix();
 
     List<ResultPoint[]> barcodeCoordinates = detect(multiple, bitMatrix);
-    if (barcodeCoordinates.isEmpty()) {
+    // Try 180, 270, 90 degree rotations, in that order
+    for (int rotate = 0; barcodeCoordinates.isEmpty() && rotate < 3; rotate++) {
       bitMatrix = bitMatrix.clone();
-      bitMatrix.rotate180();
+      if (rotate != 1) {
+        bitMatrix.rotate180();
+      } else {
+        bitMatrix.rotate90();
+      }
       barcodeCoordinates = detect(multiple, bitMatrix);
     }
     return new PDF417DetectorResult(bitMatrix, barcodeCoordinates);

core/src/test/java/com/google/zxing/common/BitMatrixTestCase.java

@@ -157,6 +157,22 @@ public final class BitMatrixTestCase extends Assert {
     }
   }
 
+  @Test
+  public void testRotate90Simple() {
+    BitMatrix matrix = new BitMatrix(3, 3);
+    matrix.set(0, 0);
+    matrix.set(0, 1);
+    matrix.set(1, 2);
+    matrix.set(2, 1);
+
+    matrix.rotate90();
+
+    assertTrue(matrix.get(0, 2));
+    assertTrue(matrix.get(1, 2));
+    assertTrue(matrix.get(2, 1));
+    assertTrue(matrix.get(1, 0));
+  }
+
   @Test
   public void testRotate180Simple() {
     BitMatrix matrix = new BitMatrix(3, 3);

core/src/test/java/com/google/zxing/pdf417/PDF417BlackBox1TestCase.java

@@ -30,7 +30,9 @@ public final class PDF417BlackBox1TestCase extends AbstractBlackBoxTestCase {
   public PDF417BlackBox1TestCase() {
     super("src/test/resources/blackbox/pdf417-1", new MultiFormatReader(), BarcodeFormat.PDF_417);
     addTest(10, 10, 0.0f);
+    addTest(10, 10, 90.0f);
     addTest(10, 10, 180.0f);
+    addTest(10, 10, 270.0f);
   }
 
 }