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/*
 * Copyright 2004-2014 ICEsoft Technologies Canada Corp.
 *
 * 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.
 */

/*
 * 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 org.icefaces.ace.util.zxing.common;

/**
 * 

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.

* *

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.

* *

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.

* * @author Sean Owen * @author [email protected] (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]; } /** *

Gets the requested bit, where true means black.

* * @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; } /** *

Sets the given bit to true.

* * @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); } /** *

Flips the given bit.

* * @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; } } /** *

Sets a square region of the bit matrix to true.

* * @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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