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Diffstat (limited to 'libraries/zxing/src/com/google/zxing/common/BitMatrix.java')
| -rw-r--r-- | libraries/zxing/src/com/google/zxing/common/BitMatrix.java | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/libraries/zxing/src/com/google/zxing/common/BitMatrix.java b/libraries/zxing/src/com/google/zxing/common/BitMatrix.java new file mode 100644 index 000000000..8bf75b289 --- /dev/null +++ b/libraries/zxing/src/com/google/zxing/common/BitMatrix.java @@ -0,0 +1,247 @@ +/*
+ * 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;
+
+/**
+ * <p>Represents a 2D matrix of bits. In function arguments below, and throughout the common
+ * module, x is the column position, and y is the row position. The ordering is always x, y.
+ * The origin is at the top-left.</p>
+ *
+ * <p>Internally the bits are represented in a 1-D array of 32-bit ints. However, each row begins
+ * with a new int. This is done intentionally so that we can copy out a row into a BitArray very
+ * efficiently.</p>
+ *
+ * <p>The ordering of bits is row-major. Within each int, the least significant bits are used first,
+ * meaning they represent lower x values. This is compatible with BitArray's implementation.</p>
+ *
+ * @author Sean Owen
+ * @author dswitkin@google.com (Daniel Switkin)
+ */
+public final class BitMatrix {
+ // Just like BitArray, these need to be public so ProGuard can inline them.
+ public final int width;
+ public final int height;
+ public final int rowSize;
+ public final int[] bits;
+
+ // A helper to construct a square matrix.
+ public BitMatrix(int dimension) {
+ this(dimension, dimension);
+ }
+
+ public BitMatrix(int width, int height) {
+ if (width < 1 || height < 1) {
+ throw new IllegalArgumentException("Both dimensions must be greater than 0");
+ }
+ this.width = width;
+ this.height = height;
+ this.rowSize = (width + 31) >> 5;
+ bits = new int[rowSize * height];
+ }
+
+ /**
+ * <p>Gets the requested bit, where true means black.</p>
+ *
+ * @param x The horizontal component (i.e. which column)
+ * @param y The vertical component (i.e. which row)
+ * @return value of given bit in matrix
+ */
+ public boolean get(int x, int y) {
+ int offset = y * rowSize + (x >> 5);
+ return ((bits[offset] >>> (x & 0x1f)) & 1) != 0;
+ }
+
+ /**
+ * <p>Sets the given bit to true.</p>
+ *
+ * @param x The horizontal component (i.e. which column)
+ * @param y The vertical component (i.e. which row)
+ */
+ public void set(int x, int y) {
+ int offset = y * rowSize + (x >> 5);
+ bits[offset] |= 1 << (x & 0x1f);
+ }
+
+ /**
+ * <p>Flips the given bit.</p>
+ *
+ * @param x The horizontal component (i.e. which column)
+ * @param y The vertical component (i.e. which row)
+ */
+ public void flip(int x, int y) {
+ int offset = y * rowSize + (x >> 5);
+ bits[offset] ^= 1 << (x & 0x1f);
+ }
+
+ /**
+ * Clears all bits (sets to false).
+ */
+ public void clear() {
+ int max = bits.length;
+ for (int i = 0; i < max; i++) {
+ bits[i] = 0;
+ }
+ }
+
+ /**
+ * <p>Sets a square region of the bit matrix to true.</p>
+ *
+ * @param left The horizontal position to begin at (inclusive)
+ * @param top The vertical position to begin at (inclusive)
+ * @param width The width of the region
+ * @param height The height of the region
+ */
+ public void setRegion(int left, int top, int width, int height) {
+ if (top < 0 || left < 0) {
+ throw new IllegalArgumentException("Left and top must be nonnegative");
+ }
+ if (height < 1 || width < 1) {
+ throw new IllegalArgumentException("Height and width must be at least 1");
+ }
+ int right = left + width;
+ int bottom = top + height;
+ if (bottom > this.height || right > this.width) {
+ throw new IllegalArgumentException("The region must fit inside the matrix");
+ }
+ for (int y = top; y < bottom; y++) {
+ int offset = y * rowSize;
+ for (int x = left; x < right; x++) {
+ bits[offset + (x >> 5)] |= 1 << (x & 0x1f);
+ }
+ }
+ }
+
+ /**
+ * A fast method to retrieve one row of data from the matrix as a BitArray.
+ *
+ * @param y The row to retrieve
+ * @param row An optional caller-allocated BitArray, will be allocated if null or too small
+ * @return The resulting BitArray - this reference should always be used even when passing
+ * your own row
+ */
+ public BitArray getRow(int y, BitArray row) {
+ if (row == null || row.getSize() < width) {
+ row = new BitArray(width);
+ }
+ int offset = y * rowSize;
+ for (int x = 0; x < rowSize; x++) {
+ row.setBulk(x << 5, bits[offset + x]);
+ }
+ 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};
+ }
+
+ public int[] getBottomRightOnBit() {
+ int bitsOffset = bits.length - 1;
+ while (bitsOffset >= 0 && bits[bitsOffset] == 0) {
+ bitsOffset--;
+ }
+ if (bitsOffset < 0) {
+ return null;
+ }
+
+ int y = bitsOffset / rowSize;
+ int x = (bitsOffset % rowSize) << 5;
+
+ int theBits = bits[bitsOffset];
+ int bit = 31;
+ while ((theBits >>> bit) == 0) {
+ bit--;
+ }
+ x += bit;
+
+ return new int[] {x, y};
+ }
+
+ /**
+ * @return The width of the matrix
+ */
+ public int getWidth() {
+ return width;
+ }
+
+ /**
+ * @return The height of the matrix
+ */
+ public int getHeight() {
+ return height;
+ }
+
+ public boolean equals(Object o) {
+ if (!(o instanceof BitMatrix)) {
+ return false;
+ }
+ BitMatrix other = (BitMatrix) o;
+ if (width != other.width || height != other.height ||
+ rowSize != other.rowSize || bits.length != other.bits.length) {
+ return false;
+ }
+ for (int i = 0; i < bits.length; i++) {
+ if (bits[i] != other.bits[i]) {
+ return false;
+ }
+ }
+ return true;
+ }
+
+ public int hashCode() {
+ int hash = width;
+ hash = 31 * hash + width;
+ hash = 31 * hash + height;
+ hash = 31 * hash + rowSize;
+ for (int i = 0; i < bits.length; i++) {
+ hash = 31 * hash + bits[i];
+ }
+ return hash;
+ }
+
+ public String toString() {
+ StringBuffer result = new StringBuffer(height * (width + 1));
+ for (int y = 0; y < height; y++) {
+ for (int x = 0; x < width; x++) {
+ result.append(get(x, y) ? "X " : " ");
+ }
+ result.append('\n');
+ }
+ return result.toString();
+ }
+
+}
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