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- /*
- * Copyright 2008 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.QrCode.Internal
- {
- /// <summary>
- ///
- /// </summary>
- /// <author>Satoru Takabayashi</author>
- /// <author>Daniel Switkin</author>
- /// <author>Sean Owen</author>
- public static class MaskUtil
- {
- // Penalty weights from section 6.8.2.1
- private const int N1 = 3;
- private const int N2 = 3;
- private const int N3 = 40;
- private const int N4 = 10;
-
- /// <summary>
- /// Apply mask penalty rule 1 and return the penalty. Find repetitive cells with the same color and
- /// give penalty to them. Example: 00000 or 11111.
- /// </summary>
- /// <param name="matrix">The matrix.</param>
- /// <returns></returns>
- public static int applyMaskPenaltyRule1(ByteMatrix matrix)
- {
- return applyMaskPenaltyRule1Internal(matrix, true) + applyMaskPenaltyRule1Internal(matrix, false);
- }
-
- /// <summary>
- /// Apply mask penalty rule 2 and return the penalty. Find 2x2 blocks with the same color and give
- /// penalty to them. This is actually equivalent to the spec's rule, which is to find MxN blocks and give a
- /// penalty proportional to (M-1)x(N-1), because this is the number of 2x2 blocks inside such a block.
- /// </summary>
- /// <param name="matrix">The matrix.</param>
- /// <returns></returns>
- public static int applyMaskPenaltyRule2(ByteMatrix matrix)
- {
- int penalty = 0;
- var array = matrix.Array;
- int width = matrix.Width;
- int height = matrix.Height;
- for (int y = 0; y < height - 1; y++)
- {
- for (int x = 0; x < width - 1; x++)
- {
- int value = array[y][x];
- if (value == array[y][x + 1] && value == array[y + 1][x] && value == array[y + 1][x + 1])
- {
- penalty++;
- }
- }
- }
- return N2 * penalty;
- }
-
- /// <summary>
- /// Apply mask penalty rule 3 and return the penalty. Find consecutive cells of 00001011101 or
- /// 10111010000, and give penalty to them. If we find patterns like 000010111010000, we give
- /// penalties twice (i.e. 40 * 2).
- /// </summary>
- /// <param name="matrix">The matrix.</param>
- /// <returns></returns>
- public static int applyMaskPenaltyRule3(ByteMatrix matrix)
- {
- int numPenalties = 0;
- byte[][] array = matrix.Array;
- int width = matrix.Width;
- int height = matrix.Height;
- for (int y = 0; y < height; y++)
- {
- for (int x = 0; x < width; x++)
- {
- byte[] arrayY = array[y]; // We can at least optimize this access
- if (x + 6 < width &&
- arrayY[x] == 1 &&
- arrayY[x + 1] == 0 &&
- arrayY[x + 2] == 1 &&
- arrayY[x + 3] == 1 &&
- arrayY[x + 4] == 1 &&
- arrayY[x + 5] == 0 &&
- arrayY[x + 6] == 1 &&
- (isWhiteHorizontal(arrayY, x - 4, x) || isWhiteHorizontal(arrayY, x + 7, x + 11)))
- {
- numPenalties++;
- }
- if (y + 6 < height &&
- array[y][x] == 1 &&
- array[y + 1][x] == 0 &&
- array[y + 2][x] == 1 &&
- array[y + 3][x] == 1 &&
- array[y + 4][x] == 1 &&
- array[y + 5][x] == 0 &&
- array[y + 6][x] == 1 &&
- (isWhiteVertical(array, x, y - 4, y) || isWhiteVertical(array, x, y + 7, y + 11)))
- {
- numPenalties++;
- }
- }
- }
- return numPenalties * N3;
- }
-
- private static bool isWhiteHorizontal(byte[] rowArray, int from, int to)
- {
- for (int i = from; i < to; i++)
- {
- if (i >= 0 && i < rowArray.Length && rowArray[i] == 1)
- {
- return false;
- }
- }
- return true;
- }
-
- private static bool isWhiteVertical(byte[][] array, int col, int from, int to)
- {
- for (int i = from; i < to; i++)
- {
- if (i >= 0 && i < array.Length && array[i][col] == 1)
- {
- return false;
- }
- }
- return true;
- }
-
- /// <summary>
- /// Apply mask penalty rule 4 and return the penalty. Calculate the ratio of dark cells and give
- /// penalty if the ratio is far from 50%. It gives 10 penalty for 5% distance.
- /// </summary>
- /// <param name="matrix">The matrix.</param>
- /// <returns></returns>
- public static int applyMaskPenaltyRule4(ByteMatrix matrix)
- {
- int numDarkCells = 0;
- var array = matrix.Array;
- int width = matrix.Width;
- int height = matrix.Height;
- for (int y = 0; y < height; y++)
- {
- var arrayY = array[y];
- for (int x = 0; x < width; x++)
- {
- if (arrayY[x] == 1)
- {
- numDarkCells++;
- }
- }
- }
- var numTotalCells = matrix.Height * matrix.Width;
- var darkRatio = (double)numDarkCells / numTotalCells;
- var fivePercentVariances = (int)(Math.Abs(darkRatio - 0.5) * 20.0); // * 100.0 / 5.0
- return fivePercentVariances * N4;
- }
-
- /// <summary>
- /// Return the mask bit for "getMaskPattern" at "x" and "y". See 8.8 of JISX0510:2004 for mask
- /// pattern conditions.
- /// </summary>
- /// <param name="maskPattern">The mask pattern.</param>
- /// <param name="x">The x.</param>
- /// <param name="y">The y.</param>
- /// <returns></returns>
- public static bool getDataMaskBit(int maskPattern, int x, int y)
- {
- int intermediate, temp;
- switch (maskPattern)
- {
-
- case 0:
- intermediate = (y + x) & 0x1;
- break;
-
- case 1:
- intermediate = y & 0x1;
- break;
-
- case 2:
- intermediate = x % 3;
- break;
-
- case 3:
- intermediate = (y + x) % 3;
- break;
-
- case 4:
- intermediate = (((int)((uint)y >> 1)) + (x / 3)) & 0x1;
- break;
-
- case 5:
- temp = y * x;
- intermediate = (temp & 0x1) + (temp % 3);
- break;
-
- case 6:
- temp = y * x;
- intermediate = (((temp & 0x1) + (temp % 3)) & 0x1);
- break;
-
- case 7:
- temp = y * x;
- intermediate = (((temp % 3) + ((y + x) & 0x1)) & 0x1);
- break;
-
- default:
- throw new ArgumentException("Invalid mask pattern: " + maskPattern);
-
- }
- return intermediate == 0;
- }
-
- /// <summary>
- /// Helper function for applyMaskPenaltyRule1. We need this for doing this calculation in both
- /// vertical and horizontal orders respectively.
- /// </summary>
- /// <param name="matrix">The matrix.</param>
- /// <param name="isHorizontal">if set to <c>true</c> [is horizontal].</param>
- /// <returns></returns>
- private static int applyMaskPenaltyRule1Internal(ByteMatrix matrix, bool isHorizontal)
- {
- int penalty = 0;
- int iLimit = isHorizontal ? matrix.Height : matrix.Width;
- int jLimit = isHorizontal ? matrix.Width : matrix.Height;
- var array = matrix.Array;
- for (int i = 0; i < iLimit; i++)
- {
- int numSameBitCells = 0;
- int prevBit = -1;
- for (int j = 0; j < jLimit; j++)
- {
- int bit = isHorizontal ? array[i][j] : array[j][i];
- if (bit == prevBit)
- {
- numSameBitCells++;
- }
- else
- {
- if (numSameBitCells >= 5)
- {
- penalty += N1 + (numSameBitCells - 5);
- }
- numSameBitCells = 1; // Include the cell itself.
- prevBit = bit;
- }
- }
- if (numSameBitCells >= 5)
- {
- penalty += N1 + (numSameBitCells - 5);
- }
- }
- return penalty;
- }
- }
- }
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