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- /*
- * 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.
- */
-
- using System;
-
- namespace ZXing.Common
- {
- /// <summary>
- /// <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>
- /// </summary>
- /// <author>Sean Owen</author>
- /// <author>dswitkin@google.com (Daniel Switkin)</author>
- public sealed partial class BitMatrix
- {
- private readonly int width;
- private readonly int height;
- private readonly int rowSize;
- private readonly int[] bits;
-
- /// <returns> The width of the matrix
- /// </returns>
- public int Width
- {
- get
- {
- return width;
- }
-
- }
- /// <returns> The height of the matrix
- /// </returns>
- public int Height
- {
- get
- {
- return height;
- }
-
- }
-
- // 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 System.ArgumentException("Both dimensions must be greater than 0");
- }
- this.width = width;
- this.height = height;
- this.rowSize = (width + 31) >> 5;
- bits = new int[rowSize * height];
- }
-
- private BitMatrix(int width, int height, int rowSize, int[] bits)
- {
- this.width = width;
- this.height = height;
- this.rowSize = rowSize;
- this.bits = bits;
- }
-
- /// <summary> <p>Gets the requested bit, where true means black.</p>
- ///
- /// </summary>
- /// <param name="x">The horizontal component (i.e. which column)
- /// </param>
- /// <param name="y">The vertical component (i.e. which row)
- /// </param>
- /// <returns> value of given bit in matrix
- /// </returns>
- public bool this[int x, int y]
- {
- get
- {
- int offset = y * rowSize + (x >> 5);
- return (((int)((uint)(bits[offset]) >> (x & 0x1f))) & 1) != 0;
- }
- set
- {
- if (value)
- {
- int offset = y * rowSize + (x >> 5);
- bits[offset] |= 1 << (x & 0x1f);
- }
- }
- }
-
- /// <summary> <p>Flips the given bit.</p>
- ///
- /// </summary>
- /// <param name="x">The horizontal component (i.e. which column)
- /// </param>
- /// <param name="y">The vertical component (i.e. which row)
- /// </param>
- public void flip(int x, int y)
- {
- int offset = y * rowSize + (x >> 5);
- bits[offset] ^= 1 << (x & 0x1f);
- }
-
-
- /// <summary> <p>Sets a square region of the bit matrix to true.</p>
- ///
- /// </summary>
- /// <param name="left">The horizontal position to begin at (inclusive)
- /// </param>
- /// <param name="top">The vertical position to begin at (inclusive)
- /// </param>
- /// <param name="width">The width of the region
- /// </param>
- /// <param name="height">The height of the region
- /// </param>
- public void setRegion(int left, int top, int width, int height)
- {
- if (top < 0 || left < 0)
- {
- throw new System.ArgumentException("Left and top must be nonnegative");
- }
- if (height < 1 || width < 1)
- {
- throw new System.ArgumentException("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 System.ArgumentException("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);
- }
- }
- }
-
- /// <summary> A fast method to retrieve one row of data from the matrix as a BitArray.
- ///
- /// </summary>
- /// <param name="y">The row to retrieve
- /// </param>
- /// <param name="row">An optional caller-allocated BitArray, will be allocated if null or too small
- /// </param>
- /// <returns> The resulting BitArray - this reference should always be used even when passing
- /// your own row
- /// </returns>
- public BitArray getRow(int y, BitArray row)
- {
- if (row == null || row.Size < width)
- {
- row = new BitArray(width);
- }
- else
- {
- row.clear();
- }
- int offset = y * rowSize;
- for (int x = 0; x < rowSize; x++)
- {
- row.setBulk(x << 5, bits[offset + x]);
- }
- return row;
- }
-
- /// <summary>
- /// Sets the row.
- /// </summary>
- /// <param name="y">row to set</param>
- /// <param name="row">{@link BitArray} to copy from</param>
- public void setRow(int y, BitArray row)
- {
- Array.Copy(row.Array, 0, bits, y * rowSize, rowSize);
- }
-
-
- /// <summary>
- /// This is useful in detecting a corner of a 'pure' barcode.
- /// </summary>
- /// <returns>{x,y} coordinate of top-left-most 1 bit, or null if it is all white</returns>
- 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[] { 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 (((int)((uint)theBits >> bit)) == 0) // (theBits >>> bit)
- {
- bit--;
- }
- x += bit;
-
- return new int[] { x, y };
- }
-
- }
- }
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