com.itextpdf.barcodes.qrcode.MaskUtil Maven / Gradle / Ivy
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package com.itextpdf.barcodes.qrcode;
/**
* @author [email protected] (Satoru Takabayashi) - creator
* @author [email protected] (Daniel Switkin) - ported from C++
*/
final class MaskUtil {
private MaskUtil() {
}
/**
* 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.
* @param matrix ByteMatrix to apply the penalty rule to
* @return the rule 1 penalty
*/
public static int applyMaskPenaltyRule1(ByteMatrix matrix) {
return applyMaskPenaltyRule1Internal(matrix, true) + applyMaskPenaltyRule1Internal(matrix, false);
}
/**
* Apply mask penalty rule 2 and return the penalty. Find 2x2 blocks with the same color and give
* penalty to them.
* @param matrix ByteMatrix to apply the penalty rule to
* @return the rule 2 penalty
*/
public static int applyMaskPenaltyRule2(ByteMatrix matrix) {
int penalty = 0;
byte[][] array = matrix.getArray();
int width = matrix.getWidth();
int height = matrix.getHeight();
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 += 3;
}
}
}
return penalty;
}
/**
* 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).
* @param matrix ByteMatrix to apply the penalty rule to
* @return the rule 3 penalty
*/
public static int applyMaskPenaltyRule3(ByteMatrix matrix) {
int penalty = 0;
byte[][] array = matrix.getArray();
int width = matrix.getWidth();
int height = matrix.getHeight();
for (int y = 0; y < height; ++y) {
for (int x = 0; x < width; ++x) {
// Tried to simplify following conditions but failed.
if (x + 6 < width &&
array[y][x] == 1 &&
array[y][x + 1] == 0 &&
array[y][x + 2] == 1 &&
array[y][x + 3] == 1 &&
array[y][x + 4] == 1 &&
array[y][x + 5] == 0 &&
array[y][x + 6] == 1 &&
((x + 10 < width &&
array[y][x + 7] == 0 &&
array[y][x + 8] == 0 &&
array[y][x + 9] == 0 &&
array[y][x + 10] == 0) ||
(x - 4 >= 0 &&
array[y][x - 1] == 0 &&
array[y][x - 2] == 0 &&
array[y][x - 3] == 0 &&
array[y][x - 4] == 0))) {
penalty += 40;
}
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 &&
((y + 10 < height &&
array[y + 7][x] == 0 &&
array[y + 8][x] == 0 &&
array[y + 9][x] == 0 &&
array[y + 10][x] == 0) ||
(y - 4 >= 0 &&
array[y - 1][x] == 0 &&
array[y - 2][x] == 0 &&
array[y - 3][x] == 0 &&
array[y - 4][x] == 0))) {
penalty += 40;
}
}
}
return penalty;
}
/**
* 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. Examples:
* - 0% => 100
* - 40% => 20
* - 45% => 10
* - 50% => 0
* - 55% => 10
* - 55% => 20
* - 100% => 100
* @param matrix Bytematrix to apply the rule to
* @return the rule 4 penalty
*/
public static int applyMaskPenaltyRule4(ByteMatrix matrix) {
int numDarkCells = 0;
byte[][] array = matrix.getArray();
int width = matrix.getWidth();
int height = matrix.getHeight();
for (int y = 0; y < height; ++y) {
for (int x = 0; x < width; ++x) {
if (array[y][x] == 1) {
numDarkCells += 1;
}
}
}
int numTotalCells = matrix.getHeight() * matrix.getWidth();
double darkRatio = (double) numDarkCells / numTotalCells;
return Math.abs((int) (darkRatio * 100 - 50)) / 5 * 10;
}
/**
* Return the mask bit for "getMaskPattern" at "x" and "y". See 8.8 of JISX0510:2004 for mask
* pattern conditions.
* @param maskPattern masking pattern to use
* @param x width coordiante
* @param y height-coordinate
* @return the mask bit at that position
*/
public static boolean getDataMaskBit(int maskPattern, int x, int y) {
if (!QRCode.isValidMaskPattern(maskPattern)) {
throw new IllegalArgumentException("Invalid mask pattern");
}
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 = ((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 IllegalArgumentException("Invalid mask pattern: " + maskPattern);
}
return intermediate == 0;
}
// Helper function for applyMaskPenaltyRule1. We need this for doing this calculation in both
// vertical and horizontal orders respectively.
private static int applyMaskPenaltyRule1Internal(ByteMatrix matrix, boolean isHorizontal) {
int penalty = 0;
int numSameBitCells = 0;
int prevBit = -1;
// Horizontal mode:
// for (int i = 0; i < matrix.height(); ++i) {
// for (int j = 0; j < matrix.width(); ++j) {
// int bit = matrix.get(i, j);
// Vertical mode:
// for (int i = 0; i < matrix.width(); ++i) {
// for (int j = 0; j < matrix.height(); ++j) {
// int bit = matrix.get(j, i);
int iLimit = isHorizontal ? matrix.getHeight() : matrix.getWidth();
int jLimit = isHorizontal ? matrix.getWidth() : matrix.getHeight();
byte[][] array = matrix.getArray();
for (int i = 0; i < iLimit; ++i) {
for (int j = 0; j < jLimit; ++j) {
int bit = isHorizontal ? array[i][j] : array[j][i];
if (bit == prevBit) {
numSameBitCells += 1;
// Found five repetitive cells with the same color (bit).
// We'll give penalty of 3.
if (numSameBitCells == 5) {
penalty += 3;
} else if (numSameBitCells > 5) {
// After five repetitive cells, we'll add the penalty one
// by one.
penalty += 1;
}
} else {
// Include the cell itself.
numSameBitCells = 1;
prevBit = bit;
}
}
// Clear at each row/column.
numSameBitCells = 0;
}
return penalty;
}
}