com.itextpdf.barcodes.qrcode.MatrixUtil Maven / Gradle / Ivy
/*
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Authors: Apryse Software.
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* The remainder is x^11 + x^10 + x^7 + x^4 + x^2
* Encode it in binary: 110010010100
* The return value is 0xc94 (1100 1001 0100)
*
* Since all coefficients in the polynomials are 1 or 0, we can do the calculation by bit
* operations. We don't care if cofficients are positive or negative.
* @param value the bitstring to calculate the BCH Code from
* @param poly the polynomial in GF[2^n] to use
*/
public static int calculateBCHCode(int value, int poly) {
// If poly is "1 1111 0010 0101" (version info poly), msbSetInPoly is 13. We'll subtract 1
// from 13 to make it 12.
int msbSetInPoly = findMSBSet(poly);
value <<= msbSetInPoly - 1;
// Do the division business using exclusive-or operations.
while (findMSBSet(value) >= msbSetInPoly) {
value ^= poly << (findMSBSet(value) - msbSetInPoly);
}
// Now the "value" is the remainder (i.e. the BCH code)
return value;
}
/**
* Make bit vector of type information. On success, store the result in "bits".
* Encode error correction level and mask pattern. See 8.9 of JISX0510:2004 (p.45) for details.
* @param ecLevel error correction level of the QR code
* @param maskPattern masking pattern to use
* @param bits Vactor of bits to contain the result
* @throws WriterException
*/
public static void makeTypeInfoBits(ErrorCorrectionLevel ecLevel, int maskPattern, BitVector bits)
throws WriterException {
if (!QRCode.isValidMaskPattern(maskPattern)) {
throw new WriterException("Invalid mask pattern");
}
int typeInfo = (ecLevel.getBits() << 3) | maskPattern;
bits.appendBits(typeInfo, 5);
int bchCode = calculateBCHCode(typeInfo, TYPE_INFO_POLY);
bits.appendBits(bchCode, 10);
BitVector maskBits = new BitVector();
maskBits.appendBits(TYPE_INFO_MASK_PATTERN, 15);
bits.xor(maskBits);
// Just in case.
if (bits.size() != 15) {
throw new WriterException("should not happen but we got: " + bits.size());
}
}
//
//
/**
* Make bit vector of version information. On success, store the result in "bits".
* See 8.10 of JISX0510:2004 (p.45) for details.
* @param version Version of the QR-code
* @param bits Vector of bits to contain the result
* @throws WriterException
*/
public static void makeVersionInfoBits(int version, BitVector bits) throws WriterException {
bits.appendBits(version, 6);
int bchCode = calculateBCHCode(version, VERSION_INFO_POLY);
bits.appendBits(bchCode, 12);
// Just in case.
if (bits.size() != 18) {
throw new WriterException("should not happen but we got: " + bits.size());
}
}
// Check if "value" is empty.
private static boolean isEmpty(byte value) {
return value == (byte) 0xff;
}
// Check if "value" is valid.
private static boolean isValidValue(byte value) {
// Empty.
return (value == (byte) 0xff ||
// Light (white).
value == 0 ||
// Dark (black).
value == 1);
}
private static void embedTimingPatterns(ByteMatrix matrix) throws WriterException {
// -8 is for skipping position detection patterns (size 7), and two horizontal/vertical
// separation patterns (size 1). Thus, 8 = 7 + 1.
for (int i = 8; i < matrix.getWidth() - 8; ++i) {
int bit = (i + 1) % 2;
// Horizontal line.
if (!isValidValue(matrix.get(i, 6))) {
throw new WriterException();
}
if (isEmpty(matrix.get(i, 6))) {
matrix.set(i, 6, bit);
}
// Vertical line.
if (!isValidValue(matrix.get(6, i))) {
throw new WriterException();
}
if (isEmpty(matrix.get(6, i))) {
matrix.set(6, i, bit);
}
}
}
// Embed the lonely dark dot at left bottom corner. JISX0510:2004 (p.46)
private static void embedDarkDotAtLeftBottomCorner(ByteMatrix matrix) throws WriterException {
if (matrix.get(8, matrix.getHeight() - 8) == 0) {
throw new WriterException();
}
matrix.set(8, matrix.getHeight() - 8, 1);
}
private static void embedHorizontalSeparationPattern(int xStart, int yStart,
ByteMatrix matrix) throws WriterException {
// We know the width and height.
if (HORIZONTAL_SEPARATION_PATTERN[0].length != 8 || HORIZONTAL_SEPARATION_PATTERN.length != 1) {
throw new WriterException("Bad horizontal separation pattern");
}
for (int x = 0; x < 8; ++x) {
if (!isEmpty(matrix.get(xStart + x, yStart))) {
throw new WriterException();
}
matrix.set(xStart + x, yStart, HORIZONTAL_SEPARATION_PATTERN[0][x]);
}
}
private static void embedVerticalSeparationPattern(int xStart, int yStart,
ByteMatrix matrix) throws WriterException {
// We know the width and height.
if (VERTICAL_SEPARATION_PATTERN[0].length != 1 || VERTICAL_SEPARATION_PATTERN.length != 7) {
throw new WriterException("Bad vertical separation pattern");
}
for (int y = 0; y < 7; ++y) {
if (!isEmpty(matrix.get(xStart, yStart + y))) {
throw new WriterException();
}
matrix.set(xStart, yStart + y, VERTICAL_SEPARATION_PATTERN[y][0]);
}
}
// Note that we cannot unify the function with embedPositionDetectionPattern() despite they are
// almost identical, since we cannot write a function that takes 2D arrays in different sizes in
// C/C++. We should live with the fact.
private static void embedPositionAdjustmentPattern(int xStart, int yStart,
ByteMatrix matrix) throws WriterException {
// We know the width and height.
if (POSITION_ADJUSTMENT_PATTERN[0].length != 5 || POSITION_ADJUSTMENT_PATTERN.length != 5) {
throw new WriterException("Bad position adjustment");
}
for (int y = 0; y < 5; ++y) {
for (int x = 0; x < 5; ++x) {
if (!isEmpty(matrix.get(xStart + x, yStart + y))) {
throw new WriterException();
}
matrix.set(xStart + x, yStart + y, POSITION_ADJUSTMENT_PATTERN[y][x]);
}
}
}
private static void embedPositionDetectionPattern(int xStart, int yStart,
ByteMatrix matrix) throws WriterException {
// We know the width and height.
if (POSITION_DETECTION_PATTERN[0].length != 7 || POSITION_DETECTION_PATTERN.length != 7) {
throw new WriterException("Bad position detection pattern");
}
for (int y = 0; y < 7; ++y) {
for (int x = 0; x < 7; ++x) {
if (!isEmpty(matrix.get(xStart + x, yStart + y))) {
throw new WriterException();
}
matrix.set(xStart + x, yStart + y, POSITION_DETECTION_PATTERN[y][x]);
}
}
}
// Embed position detection patterns and surrounding vertical/horizontal separators.
private static void embedPositionDetectionPatternsAndSeparators(ByteMatrix matrix) throws WriterException {
// Embed three big squares at corners.
int pdpWidth = POSITION_DETECTION_PATTERN[0].length;
// Left top corner.
embedPositionDetectionPattern(0, 0, matrix);
// Right top corner.
embedPositionDetectionPattern(matrix.getWidth() - pdpWidth, 0, matrix);
// Left bottom corner.
embedPositionDetectionPattern(0, matrix.getWidth() - pdpWidth, matrix);
// Embed horizontal separation patterns around the squares.
int hspWidth = HORIZONTAL_SEPARATION_PATTERN[0].length;
// Left top corner.
embedHorizontalSeparationPattern(0, hspWidth - 1, matrix);
// Right top corner.
embedHorizontalSeparationPattern(matrix.getWidth() - hspWidth,
hspWidth - 1, matrix);
// Left bottom corner.
embedHorizontalSeparationPattern(0, matrix.getWidth() - hspWidth, matrix);
// Embed vertical separation patterns around the squares.
int vspSize = VERTICAL_SEPARATION_PATTERN.length;
// Left top corner.
embedVerticalSeparationPattern(vspSize, 0, matrix);
// Right top corner.
embedVerticalSeparationPattern(matrix.getHeight() - vspSize - 1, 0, matrix);
// Left bottom corner.
embedVerticalSeparationPattern(vspSize, matrix.getHeight() - vspSize,
matrix);
}
// Embed position adjustment patterns if need be.
private static void maybeEmbedPositionAdjustmentPatterns(int version, ByteMatrix matrix)
throws WriterException {
// The patterns appear if version >= 2
if (version < 2) {
return;
}
int index = version - 1;
int[] coordinates = POSITION_ADJUSTMENT_PATTERN_COORDINATE_TABLE[index];
int numCoordinates = POSITION_ADJUSTMENT_PATTERN_COORDINATE_TABLE[index].length;
for (int i = 0; i < numCoordinates; ++i) {
for (int j = 0; j < numCoordinates; ++j) {
int y = coordinates[i];
int x = coordinates[j];
if (x == -1 || y == -1) {
continue;
}
// If the cell is unset, we embed the position adjustment pattern here.
if (isEmpty(matrix.get(x, y))) {
// -2 is necessary since the x/y coordinates point to the center of the pattern, not the
// left top corner.
embedPositionAdjustmentPattern(x - 2, y - 2, matrix);
}
}
}
}
}