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Initial commit of QR Code generator library, in Java and JavaScript.

This commit is contained in:
Nayuki Minase 2016-04-10 06:11:57 +00:00
commit 72921ece29
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/*
* QR Code generator library (Java)
*
* Copyright (c) 2016 Project Nayuki
* https://www.nayuki.io/page/qr-code-generator-library
*
* (MIT License)
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
* - The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* - The Software is provided "as is", without warranty of any kind, express or
* implied, including but not limited to the warranties of merchantability,
* fitness for a particular purpose and noninfringement. In no event shall the
* authors or copyright holders be liable for any claim, damages or other
* liability, whether in an action of contract, tort or otherwise, arising from,
* out of or in connection with the Software or the use or other dealings in the
* Software.
*/
package io.nayuki.qrcodegen;
import java.util.Arrays;
/**
* An appendable sequence of bits. Bits are packed in big endian within a byte.
*/
final class BitBuffer {
/*---- Fields ----*/
private byte[] data;
private int bitLength;
/*---- Constructor ----*/
// Creates an empty bit buffer (length 0).
public BitBuffer() {
data = new byte[16];
bitLength = 0;
}
/*---- Methods ----*/
// Returns the number of bits in the buffer, which is a non-negative value.
public int bitLength() {
return bitLength;
}
// Returns a copy of all bytes, padding up to the nearest byte.
public byte[] getBytes() {
return Arrays.copyOf(data, (bitLength + 7) / 8);
}
// Appends the given number of bits of the given value to this sequence.
// If 0 <= len <= 31, then this requires 0 <= val < 2^len.
public void appendBits(int val, int len) {
if (len < 0 || len > 32 || len < 32 && (val & ((1 << len) - 1)) != val)
throw new IllegalArgumentException("Value out of range");
ensureCapacity(bitLength + len);
for (int i = len - 1; i >= 0; i--, bitLength++) // Append bit by bit
data[bitLength >>> 3] |= ((val >>> i) & 1) << (7 - (bitLength & 7));
}
// Appends the data of the given segment to this bit buffer.
public void appendData(QrSegment seg) {
if (seg == null)
throw new NullPointerException();
ensureCapacity(bitLength + seg.bitLength);
for (int i = 0; i < seg.bitLength; i++, bitLength++) { // Append bit by bit
int bit = (seg.getByte(i >>> 3) >>> (7 - (i & 7))) & 1;
data[bitLength >>> 3] |= bit << (7 - (bitLength & 7));
}
}
// Expands the buffer if necessary, so that it can hold at least the given bit length.
private void ensureCapacity(int newBitLen) {
while (data.length < newBitLen)
data = Arrays.copyOf(data, data.length * 2);
}
}

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/*
* QR Code generator library (Java)
*
* Copyright (c) 2016 Project Nayuki
* https://www.nayuki.io/page/qr-code-generator-library
*
* (MIT License)
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
* - The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* - The Software is provided "as is", without warranty of any kind, express or
* implied, including but not limited to the warranties of merchantability,
* fitness for a particular purpose and noninfringement. In no event shall the
* authors or copyright holders be liable for any claim, damages or other
* liability, whether in an action of contract, tort or otherwise, arising from,
* out of or in connection with the Software or the use or other dealings in the
* Software.
*/
package io.nayuki.qrcodegen;
import java.awt.image.BufferedImage;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.List;
/**
* Represents an immutable square grid of black and white cells for a QR Code symbol, and
* provides static functions to create a QR Code from user-supplied textual or binary data.
* <p>This class covers the QR Code model 2 specification, supporting all versions (sizes)
* from 1 to 40, all 4 error correction levels, and only 3 character encoding modes.</p>
*/
public final class QrCode {
/*---- Public static factory functions ----*/
/**
* Returns a QR Code symbol representing the specified Unicode text string at the specified error correction level.
* As a conservative upper bound, this function is guaranteed to succeed for strings that have 738 or fewer Unicode
* code points (not UTF-16 code units). The smallest possible QR Code version is automatically chosen for the output.
* @param text the text to be encoded, which can be any Unicode string
* @param ecl the error correction level to use
* @return a QR Code representing the text
* @throws NullPointerException if the text or error correction level is {@code null}
* @throws IllegalArgumentException if the text fails to fit in the largest version QR Code, which means it is too long
*/
public static QrCode encodeText(String text, Ecc ecl) {
if (text == null || ecl == null)
throw new NullPointerException();
QrSegment seg; // Select the most efficient segment encoding automatically
if (QrSegment.NUMERIC_REGEX.matcher(text).matches())
seg = QrSegment.makeNumeric(text);
else if (QrSegment.ALPHANUMERIC_REGEX.matcher(text).matches())
seg = QrSegment.makeAlphanumeric(text);
else
seg = QrSegment.makeBytes(text.getBytes(StandardCharsets.UTF_8));
return encodeSegments(Arrays.asList(seg), ecl);
}
/**
* Returns a QR Code symbol representing the specified binary data string at the specified error correction level.
* This function always encodes using the binary segment mode, not any text mode. The maximum number of
* bytes allowed is 2953. The smallest possible QR Code version is automatically chosen for the output.
* @param data the binary data to encode
* @param ecl the error correction level to use
* @return a QR Code representing the binary data
* @throws NullPointerException if the data or error correction level is {@code null}
* @throws IllegalArgumentException if the data fails to fit in the largest version QR Code, which means it is too long
*/
public static QrCode encodeBinary(byte[] data, Ecc ecl) {
if (data == null || ecl == null)
throw new NullPointerException();
QrSegment seg = QrSegment.makeBytes(data);
return encodeSegments(Arrays.asList(seg), ecl);
}
/**
* Returns a QR Code symbol representing the specified data segments at the specified error
* correction level. The smallest possible QR Code version is automatically chosen for the output.
* <p>This function allows the user to create a custom sequence of segments that switches
* between modes (such as alphanumeric and binary) to encode text more efficiently. This
* function is considered to be lower level than simply encoding text or binary data.</p>
* @param segs the segments to encode
* @param ecl the error correction level to use
* @return a QR Code representing the segments
* @throws NullPointerException if the list of segments, a segment, or the error correction level is {@code null}
* @throws IllegalArgumentException if the data fails to fit in the largest version QR Code, which means it is too long
*/
public static QrCode encodeSegments(List<QrSegment> segs, Ecc ecl) {
if (segs == null || ecl == null)
throw new NullPointerException();
// Find the minimal version number to use
int version, dataCapacityBits;
outer:
for (version = 1; ; version++) { // Increment until the data fits in the QR Code
if (version > 40) // All versions could not fit the given data
throw new IllegalArgumentException("Data too long");
dataCapacityBits = getNumDataCodewords(version, ecl) * 8; // Number of data bits available
// Calculate the total number of bits needed at this version number
// to encode all the segments (i.e. segment metadata and payloads)
int dataUsedBits = 0;
for (QrSegment seg : segs) {
if (seg == null)
throw new NullPointerException();
if (seg.numChars < 0)
throw new AssertionError();
int ccbits = seg.mode.numCharCountBits(version);
if (seg.numChars >= (1 << ccbits)) {
// Segment length value doesn't fit in the length field's bit-width, so fail immediately
continue outer;
}
dataUsedBits += 4 + ccbits + seg.bitLength;
}
if (dataUsedBits <= dataCapacityBits)
break; // This version number is found to be suitable
}
// Create the data bit string by concatenating all segments
BitBuffer bb = new BitBuffer();
for (QrSegment seg : segs) {
bb.appendBits(seg.mode.modeBits, 4);
bb.appendBits(seg.numChars, seg.mode.numCharCountBits(version));
bb.appendData(seg);
}
// Add terminator and pad up to a byte if applicable
bb.appendBits(0, Math.min(4, dataCapacityBits - bb.bitLength()));
bb.appendBits(0, (8 - bb.bitLength() % 8) % 8);
// Pad with alternate bytes until data capacity is reached
for (int padByte = 0xEC; bb.bitLength() < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
bb.appendBits(padByte, 8);
if (bb.bitLength() % 8 != 0)
throw new AssertionError();
// Create the QR Code symbol
return new QrCode(version, ecl, bb.getBytes(), -1);
}
/*---- Instance fields ----*/
// Public immutable scalar parameters
/** This QR Code symbol's version number, which is always between 1 and 40 (inclusive). */
public final int version;
/** The width and height of this QR Code symbol, measured in modules.
* Always equal to version &times; 4 + 17, in the range 21 to 177. */
public final int size;
/** The error correction level used in this QR Code symbol. Never {@code null}. */
public final Ecc errorCorrectionLevel;
/** The mask pattern used in this QR Code symbol, in the range 0 to 7 (i.e. unsigned 3-bit integer).
* Note that even if a constructor was called with automatic masking requested
* (mask = -1), the resulting object will still have a mask value between 0 and 7. */
public final int mask;
// Private grids of modules/pixels (conceptually immutable)
private boolean[][] modules; // The modules of this QR Code symbol (false = white, true = black)
private boolean[][] isFunction; // Indicates function modules that are not subjected to masking
/*---- Constructors ----*/
/**
* Creates a new QR Code symbol with the specified version number, error correction level, binary data string, and mask number.
* <p>This cumbersome constructor can be invoked directly by the user, but is considered
* to be even lower level than {@link #encodeSegments(List,Ecc)}.</p>
* @param ver the version number to use, which must be in the range 1 to 40, inclusive
* @param ecl the error correction level to use
* @param dataCodewords the raw binary user data to encode
* @param mask the mask pattern to use, which is either -1 for automatic choice or from 0 to 7 for fixed choice
* @throws NullPointerException if the byte array or error correction level is {@code null}
* @throws IllegalArgumentException if the version or mask value is out of range
*/
public QrCode(int ver, Ecc ecl, byte[] dataCodewords, int mask) {
// Check arguments
if (ecl == null)
throw new NullPointerException();
if (ver < 1 || ver > 40 || mask < -1 || mask > 7)
throw new IllegalArgumentException("Value out of range");
if (dataCodewords == null)
throw new NullPointerException();
// Initialize fields
version = ver;
size = ver * 4 + 17;
errorCorrectionLevel = ecl;
modules = new boolean[size][size]; // Entirely white grid
isFunction = new boolean[size][size];
// Draw function patterns, draw all codewords, do masking
drawFunctionPatterns();
byte[] allCodewords = appendErrorCorrection(dataCodewords);
drawCodewords(allCodewords);
this.mask = handleConstructorMasking(mask);
}
/**
* Creates a new QR Code symbol based on the specified existing object, but with a potentially
* different mask pattern. The version, error correction level, codewords, etc. of the newly
* created object are all identical to the argument object; only the mask may differ.
* @param qr the existing QR Code to copy and modify
* @param mask the new mask pattern, 0 to 7 to force a fixed choice or -1 for an automatic choice
* @throws NullPointerException if the QR Code is {@code null}
* @throws IllegalArgumentException if the mask value is out of range
*/
public QrCode(QrCode qr, int mask) {
// Check arguments
if (qr == null)
throw new NullPointerException();
if (mask < -1 || mask > 7)
throw new IllegalArgumentException("Mask value out of range");
// Copy scalar fields
version = qr.version;
size = qr.size;
errorCorrectionLevel = qr.errorCorrectionLevel;
// Handle grid fields
isFunction = qr.isFunction; // Shallow copy because the data is read-only
modules = qr.modules.clone(); // Deep copy
for (int i = 0; i < modules.length; i++)
modules[i] = modules[i].clone();
// Handle masking
applyMask(qr.mask); // Undo old mask
this.mask = handleConstructorMasking(mask);
}
/*---- Public instance methods ----*/
/**
* Returns the color of the module (pixel) at the specified coordinates, which is either 0 for white or 1 for black. The top
* left corner has the coordinates (x=0, y=0). If the specified coordinates are out of bounds, then 0 (white) is returned.
* @param x the x coordinate, where 0 is the left edge and size&minus;1 is the right edge
* @param y the y coordinate, where 0 is the top edge and size&minus;1 is the bottom edge
* @return the module's color, which is either 0 (white) or 1 (black)
*/
public int getModule(int x, int y) {
if (x < 0 || x >= size || y < 0 || y >= size)
return 0; // Infinite white border
else
return modules[y][x] ? 1 : 0;
}
/**
* Returns a new image object representing this QR Code, with the specified module scale and number
* of border modules. For example, the arguments scale=10, border=4 means to pad the QR Code symbol
* with 4 white border modules on all four edges, then use 10*10 pixels to represent each module.
* The resulting image only contains the hex colors 000000 and FFFFFF.
* @param scale the module scale factor, which must be positive
* @param border the number of border modules to add, which must be non-negative
* @return an image representing this QR Code, with padding and scaling
* @throws IllegalArgumentException if the scale or border is out of range
*/
public BufferedImage toImage(int scale, int border) {
if (scale <= 0 || border < 0)
throw new IllegalArgumentException("Value out of range");
BufferedImage result = new BufferedImage((size + border * 2) * scale, (size + border * 2) * scale, BufferedImage.TYPE_INT_RGB);
for (int y = 0; y < result.getHeight(); y++) {
for (int x = 0; x < result.getWidth(); x++) {
int val = getModule(x / scale - border, y / scale - border); // 0 or 1
result.setRGB(x, y, val == 1 ? 0x000000 : 0xFFFFFF);
}
}
return result;
}
/**
* Based on the specified number of border modules to add as padding, this returns a
* string whose contents represents an SVG XML file that depicts this QR Code symbol.
* Note that Unix newlines (\n) are always used, regardless of the platform.
* @param border the number of border modules to add, which must be non-negative
* @return a string representing this QR Code as an SVG document
*/
public String toSvgString(int border) {
if (border < 0)
throw new IllegalArgumentException("Border must be non-negative");
StringBuilder sb = new StringBuilder();
sb.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
sb.append("<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\" \"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\">\n");
sb.append(String.format("<svg xmlns=\"http://www.w3.org/2000/svg\" version=\"1.1\" viewBox=\"0 0 %1$d %1$d\">\n", size + border * 2));
sb.append("\t<path d=\"");
boolean head = true;
for (int y = -border; y < size + border; y++) {
for (int x = -border; x < size + border; x++) {
if (getModule(x, y) == 1) {
if (head)
head = false;
else
sb.append(" ");
sb.append(String.format("M%d,%dh1v1h-1z", x + border, y + border));
}
}
}
sb.append("\" fill=\"#000000\" stroke-width=\"0\"/>\n");
sb.append("</svg>\n");
return sb.toString();
}
/*---- Private helper methods for constructor: Drawing function modules ----*/
private void drawFunctionPatterns() {
// Draw the horizontal and vertical timing patterns
for (int i = 0; i < size; i++) {
setFunctionModule(6, i, i % 2 == 0);
setFunctionModule(i, 6, i % 2 == 0);
}
// Draw 3 finder patterns (all corners except bottom right; overwrites some timing modules)
drawFinderPattern(3, 3);
drawFinderPattern(size - 4, 3);
drawFinderPattern(3, size - 4);
// Draw the numerous alignment patterns
int[] alignPatPos = getAlignmentPatternPositions(version);
int numAlign = alignPatPos.length;
for (int i = 0; i < numAlign; i++) {
for (int j = 0; j < numAlign; j++) {
if (i == 0 && j == 0 || i == 0 && j == numAlign - 1 || i == numAlign - 1 && j == 0)
continue; // Skip the three finder corners
else
drawAlignmentPattern(alignPatPos[i], alignPatPos[j]);
}
}
// Draw configuration data
drawFormatBits(0); // Dummy mask value; overwritten later in the constructor
drawVersion();
}
// Draws two copies of the format bits (with its own error correction code)
// based on this object's error correction level and mask fields.
private void drawFormatBits(int mask) {
// Calculate error correction code and pack bits
int data = errorCorrectionLevel.formatBits << 3 | mask; // errCorrLvl is uint2, mask is uint3
int rem = data;
for (int i = 0; i < 10; i++)
rem = (rem << 1) ^ ((rem >>> 9) * 0x537);
data = data << 10 | rem;
data ^= 0x5412; // uint15
if ((data & ((1 << 15) - 1)) != data)
throw new AssertionError();
// Draw first copy
for (int i = 0; i <= 5; i++)
setFunctionModule(8, i, ((data >>> i) & 1) != 0);
setFunctionModule(8, 7, ((data >>> 6) & 1) != 0);
setFunctionModule(8, 8, ((data >>> 7) & 1) != 0);
setFunctionModule(7, 8, ((data >>> 8) & 1) != 0);
for (int i = 9; i < 15; i++)
setFunctionModule(14 - i, 8, ((data >>> i) & 1) != 0);
// Draw second copy
for (int i = 0; i <= 7; i++)
setFunctionModule(size - 1 - i, 8, ((data >>> i) & 1) != 0);
for (int i = 8; i < 15; i++)
setFunctionModule(8, size - 15 + i, ((data >>> i) & 1) != 0);
setFunctionModule(8, size - 8, true);
}
// Draws two copies of the version bits (with its own error correction code),
// based on this object's version field (which only has an effect for 7 <= version <= 40).
private void drawVersion() {
if (version < 7)
return;
// Calculate error correction code and pack bits
int rem = version; // version is uint6, in the range [7, 40]
for (int i = 0; i < 12; i++)
rem = (rem << 1) ^ ((rem >>> 11) * 0x1F25);
int data = version << 12 | rem; // uint18
if ((data & ((1 << 18) - 1)) != data)
throw new AssertionError();
// Draw two copies
for (int i = 0; i < 18; i++) {
boolean bit = ((data >>> i) & 1) != 0;
setFunctionModule(size - 11 + i % 3, i / 3, bit);
setFunctionModule(i / 3, size - 11 + i % 3, bit);
}
}
// Draws a 9*9 finder pattern including the border separator, with the center module at (x, y).
private void drawFinderPattern(int x, int y) {
for (int i = -4; i <= 4; i++) {
for (int j = -4; j <= 4; j++) {
int dist = Math.max(Math.abs(i), Math.abs(j)); // Chebyshev/infinity norm
int xx = x + j;
int yy = y + i;
if (0 <= xx && xx < size && 0 <= yy && yy < size)
setFunctionModule(xx, yy, dist != 2 && dist != 4);
}
}
}
// Draws a 5*5 alignment pattern, with the center module at (x, y).
private void drawAlignmentPattern(int x, int y) {
for (int i = -2; i <= 2; i++) {
for (int j = -2; j <= 2; j++)
setFunctionModule(x + j, y + i, Math.max(Math.abs(i), Math.abs(j)) != 1);
}
}
// Sets the color of a module and marks it as a function module.
// Only used by the constructor. Coordinates must be in range.
private void setFunctionModule(int x, int y, boolean isBlack) {
modules[y][x] = isBlack;
isFunction[y][x] = true;
}
/*---- Private helper methods for constructor: Codewords and masking ----*/
// Returns a new byte string representing the given data with the appropriate error correction
// codewords appended to it, based on this object's version and error correction level.
private byte[] appendErrorCorrection(byte[] data) {
if (data.length != getNumDataCodewords(version, errorCorrectionLevel))
throw new IllegalArgumentException();
int numBlocks = NUM_ERROR_CORRECTION_BLOCKS[errorCorrectionLevel.ordinal()][version];
int numEcc = NUM_ERROR_CORRECTION_CODEWORDS[errorCorrectionLevel.ordinal()][version];
if (numEcc % numBlocks != 0)
throw new AssertionError();
int eccLen = numEcc / numBlocks;
int numShortBlocks = numBlocks - getNumRawDataModules(version) / 8 % numBlocks;
int shortBlockLen = getNumRawDataModules(version) / 8 / numBlocks;
byte[][] blocks = new byte[numBlocks][];
ReedSolomonGenerator rs = new ReedSolomonGenerator(eccLen);
for (int i = 0, k = 0; i < numBlocks; i++) {
byte[] dat = Arrays.copyOfRange(data, k, k + shortBlockLen - eccLen + (i < numShortBlocks ? 0 : 1));
byte[] block = Arrays.copyOf(dat, shortBlockLen + 1);
k += dat.length;
byte[] ecc = rs.getRemainder(dat);
System.arraycopy(ecc, 0, block, block.length - eccLen, ecc.length);
blocks[i] = block;
}
byte[] result = new byte[getNumRawDataModules(version) / 8];
for (int i = 0, k = 0; i < blocks[0].length; i++) {
for (int j = 0; j < blocks.length; j++) {
if (i != shortBlockLen - eccLen || j >= numShortBlocks) {
result[k] = blocks[j][i];
k++;
}
}
}
return result;
}
// Draws the given sequence of 8-bit codewords (data and error correction) onto the entire
// data area of this QR Code symbol. Function modules need to be marked off before this is called.
private void drawCodewords(byte[] data) {
if (data == null)
throw new NullPointerException();
if (data.length != getNumRawDataModules(version) / 8)
throw new IllegalArgumentException();
int i = 0; // Bit index into the data
// Do the funny zigzag scan
for (int right = size - 1; right >= 1; right -= 2) { // Index of right column in each column pair
if (right == 6)
right = 5;
for (int vert = 0; vert < size; vert++) { // Vertical counter
for (int j = 0; j < 2; j++) {
int x = right - j; // Actual x coordinate
boolean upwards = ((right & 2) == 0) ^ (x < 6);
int y = upwards ? size - 1 - vert : vert; // Actual y coordinate
if (!isFunction[y][x] && i < data.length * 8) {
modules[y][x] = (data[i >>> 3] >>> (7 - (i & 7)) & 1) != 0;
i++;
}
}
}
}
if (i != data.length * 8)
throw new AssertionError();
}
// XORs the data modules in this QR Code with the given mask pattern. Due to XOR's mathematical
// properties, calling applyMask(m) twice with the same value is equivalent to no change at all.
// This means it is possible to apply a mask, undo it, and try another mask. Note that a final
// well-formed QR Code symbol needs exactly one mask applied (not zero, not two, etc.).
private void applyMask(int mask) {
if (mask < 0 || mask > 7)
throw new IllegalArgumentException("Mask value out of range");
for (int y = 0; y < size; y++) {
for (int x = 0; x < size; x++) {
boolean invert;
switch (mask) {
case 0: invert = (x + y) % 2 == 0; break;
case 1: invert = y % 2 == 0; break;
case 2: invert = x % 3 == 0; break;
case 3: invert = (x + y) % 3 == 0; break;
case 4: invert = (x / 3 + y / 2) % 2 == 0; break;
case 5: invert = x * y % 2 + x * y % 3 == 0; break;
case 6: invert = (x * y % 2 + x * y % 3) % 2 == 0; break;
case 7: invert = ((x + y) % 2 + x * y % 3) % 2 == 0; break;
default: throw new AssertionError();
}
modules[y][x] ^= invert & !isFunction[y][x];
}
}
}
// A messy helper function for the constructors. This QR Code must be in an unmasked state when this
// method is called. The given argument is the requested mask, which is -1 for auto or 0 to 7 for fixed.
// This method applies and returns the actual mask chosen, from 0 to 7.
private int handleConstructorMasking(int mask) {
if (mask == -1) { // Automatically choose best mask
int minPenalty = Integer.MAX_VALUE;
for (int i = 0; i < 8; i++) {
drawFormatBits(i);
applyMask(i);
int penalty = getPenaltyScore();
if (penalty < minPenalty) {
mask = i;
minPenalty = penalty;
}
applyMask(i); // Undoes the mask due to XOR
}
}
if (mask < 0 || mask > 7)
throw new AssertionError();
drawFormatBits(mask); // Overwrite old format bits
applyMask(mask); // Apply the final choice of mask
return mask; // The caller shall assign this value to the final-declared field
}
// Calculates and returns the penalty score based on state of this QR Code's current modules.
// This is used by the automatic mask choice algorithm to find the mask pattern that yields the lowest score.
private int getPenaltyScore() {
int result = 0;
// Adjacent modules in row having same color
for (int y = 0; y < size; y++) {
boolean colorX = modules[y][0];
for (int x = 1, runX = 1; x < size; x++) {
if (modules[y][x] != colorX) {
colorX = modules[y][x];
runX = 1;
} else {
runX++;
if (runX == 5)
result += PENALTY_N1;
else if (runX > 5)
result++;
}
}
}
// Adjacent modules in column having same color
for (int x = 0; x < size; x++) {
boolean colorY = modules[0][x];
for (int y = 1, runY = 1; y < size; y++) {
if (modules[y][x] != colorY) {
colorY = modules[y][x];
runY = 1;
} else {
runY++;
if (runY == 5)
result += PENALTY_N1;
else if (runY > 5)
result++;
}
}
}
// 2*2 blocks of modules having same color
for (int y = 0; y < size - 1; y++) {
for (int x = 0; x < size - 1; x++) {
boolean color = modules[y][x];
if ( color == modules[y][x + 1] &&
color == modules[y + 1][x] &&
color == modules[y + 1][x + 1])
result += PENALTY_N2;
}
}
// Finder-like pattern in rows
for (int y = 0; y < size; y++) {
for (int x = 0, bits = 0; x < size; x++) {
bits = ((bits << 1) & 0x7FF) | (modules[y][x] ? 1 : 0);
if (x >= 10 && (bits == 0x05D || bits == 0x5D0)) // Needs 11 bits accumulated
result += PENALTY_N3;
}
}
// Finder-like pattern in columns
for (int x = 0; x < size; x++) {
for (int y = 0, bits = 0; y < size; y++) {
bits = ((bits << 1) & 0x7FF) | (modules[y][x] ? 1 : 0);
if (y >= 10 && (bits == 0x05D || bits == 0x5D0)) // Needs 11 bits accumulated
result += PENALTY_N3;
}
}
// Balance of black and white modules
int black = 0;
for (boolean[] row : modules) {
for (boolean color : row) {
if (color)
black++;
}
}
int total = size * size;
// Find smallest k such that (45-5k)% <= dark/total <= (55+5k)%
for (int k = 0; black*20 < (9-k)*total || black*20 > (11+k)*total; k++)
result += PENALTY_N4;
return result;
}
/*---- Static helper functions ----*/
// Returns a set of positions of the alignment patterns in ascending order. These positions are
// used on both the x and y axes. Each value in the resulting array is in the range [0, 177).
// This stateless pure function could be implemented as table of 40 variable-length lists of unsigned bytes.
private static int[] getAlignmentPatternPositions(int ver) {
if (ver < 1 || ver > 40)
throw new IllegalArgumentException("Version number out of range");
else if (ver == 1)
return new int[]{};
else {
int numAlign = ver / 7 + 2;
int step;
if (ver != 32)
step = (ver * 4 + numAlign * 2 + 1) / (2 * numAlign - 2) * 2; // ceil((size - 13) / (2*numAlign - 2)) * 2
else // C-C-C-Combo breaker!
step = 26;
int[] result = new int[numAlign];
int size = ver * 4 + 17;
result[0] = 6;
for (int i = result.length - 1, pos = size - 7; i >= 1; i--, pos -= step)
result[i] = pos;
return result;
}
}
// Returns the number of raw data modules (bits) available at the given version number.
// These data modules are used for both user data codewords and error correction codewords.
// This stateless pure function could be implemented as a 40-entry lookup table.
private static int getNumRawDataModules(int ver) {
if (ver < 1 || ver > 40)
throw new IllegalArgumentException("Version number out of range");
int size = ver * 4 + 17;
int result = size * size; // Number of modules in the whole QR symbol square
result -= 64 * 3; // Subtract the three finders with separators
result -= 15 * 2 + 1; // Subtract the format information and black module
result -= (size - 16) * 2; // Subtract the timing patterns
// The four lines above are equivalent to: int result = (16 * ver + 128) * ver + 64;
if (ver >= 2) {
int numAlign = ver / 7 + 2;
result -= (numAlign - 1) * (numAlign - 1) * 25; // Subtract alignment patterns not overlapping with timing patterns
result -= (numAlign - 2) * 2 * 20; // Subtract alignment patterns that overlap with timing patterns
// The two lines above are equivalent to: result -= (25 * numAlign - 10) * numAlign - 55;
if (ver >= 7)
result -= 18 * 2; // Subtract version information
}
return result;
}
// Returns the number of 8-bit data (i.e. not error correction) codewords contained in any
// QR Code of the given version number and error correction level, with remainder bits discarded.
// This stateless pure function could be implemented as a (40*4)-cell lookup table.
private static int getNumDataCodewords(int ver, Ecc ecl) {
return getNumRawDataModules(ver) / 8 - NUM_ERROR_CORRECTION_CODEWORDS[ecl.ordinal()][ver];
}
/*---- Tables of constants ----*/
// For use in getPenaltyScore(), when evaluating which mask is best.
private static final int PENALTY_N1 = 3;
private static final int PENALTY_N2 = 3;
private static final int PENALTY_N3 = 40;
private static final int PENALTY_N4 = 10;
private static final short[][] NUM_ERROR_CORRECTION_CODEWORDS = {
// Version: (note that index 0 is for padding, and is set to an illegal value)
//0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 Error correction level
{-1, 7, 10, 15, 20, 26, 36, 40, 48, 60, 72, 80, 96, 104, 120, 132, 144, 168, 180, 196, 224, 224, 252, 270, 300, 312, 336, 360, 390, 420, 450, 480, 510, 540, 570, 570, 600, 630, 660, 720, 750}, // Low
{-1, 10, 16, 26, 36, 48, 64, 72, 88, 110, 130, 150, 176, 198, 216, 240, 280, 308, 338, 364, 416, 442, 476, 504, 560, 588, 644, 700, 728, 784, 812, 868, 924, 980, 1036, 1064, 1120, 1204, 1260, 1316, 1372}, // Medium
{-1, 13, 22, 36, 52, 72, 96, 108, 132, 160, 192, 224, 260, 288, 320, 360, 408, 448, 504, 546, 600, 644, 690, 750, 810, 870, 952, 1020, 1050, 1140, 1200, 1290, 1350, 1440, 1530, 1590, 1680, 1770, 1860, 1950, 2040}, // Quartile
{-1, 17, 28, 44, 64, 88, 112, 130, 156, 192, 224, 264, 308, 352, 384, 432, 480, 532, 588, 650, 700, 750, 816, 900, 960, 1050, 1110, 1200, 1260, 1350, 1440, 1530, 1620, 1710, 1800, 1890, 1980, 2100, 2220, 2310, 2430}, // High
};
private static final byte[][] NUM_ERROR_CORRECTION_BLOCKS = {
// Version: (note that index 0 is for padding, and is set to an illegal value)
//0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 Error correction level
{-1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 4, 4, 4, 4, 4, 6, 6, 6, 6, 7, 8, 8, 9, 9, 10, 12, 12, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 21, 22, 24, 25}, // Low
{-1, 1, 1, 1, 2, 2, 4, 4, 4, 5, 5, 5, 8, 9, 9, 10, 10, 11, 13, 14, 16, 17, 17, 18, 20, 21, 23, 25, 26, 28, 29, 31, 33, 35, 37, 38, 40, 43, 45, 47, 49}, // Medium
{-1, 1, 1, 2, 2, 4, 4, 6, 6, 8, 8, 8, 10, 12, 16, 12, 17, 16, 18, 21, 20, 23, 23, 25, 27, 29, 34, 34, 35, 38, 40, 43, 45, 48, 51, 53, 56, 59, 62, 65, 68}, // Quartile
{-1, 1, 1, 2, 4, 4, 4, 5, 6, 8, 8, 11, 11, 16, 16, 18, 16, 19, 21, 25, 25, 25, 34, 30, 32, 35, 37, 40, 42, 45, 48, 51, 54, 57, 60, 63, 66, 70, 74, 77, 81}, // High
};
/*---- Public helper enumeration ----*/
/**
* Represents the error correction level used in a QR Code symbol.
*/
public enum Ecc {
// Constants declared in ascending order of error protection.
LOW(1), MEDIUM(0), QUARTILE(3), HIGH(2);
// In the range 0 to 3 (unsigned 2-bit integer).
public final int formatBits;
// Constructor.
private Ecc(int fb) {
formatBits = fb;
}
}
/*---- Private helper class ----*/
/**
* Computes the Reed-Solomon error correction codewords for a sequence of data codewords
* at a given degree. Objects are immutable, and the state only depends on the degree.
* This class exists because the divisor polynomial does not need to be recalculated for every input.
*/
private static final class ReedSolomonGenerator {
/*-- Immutable field --*/
// Coefficients of the divisor polynomial, stored from highest to lowest power, excluding the leading term which
// is always 1. For example the polynomial x^3 + 255x^2 + 8x + 93 is stored as the uint8 array {255, 8, 93}.
private final byte[] coefficients;
/*-- Constructor --*/
/**
* Creates a Reed-Solomon ECC generator for the specified degree. This could be implemented
* as a lookup table over all possible parameter values, instead of as an algorithm.
* @param degree the divisor polynomial degree, which must be between 1 and 255
* @throws IllegalArgumentException if degree &lt; 1 or degree > 255
*/
public ReedSolomonGenerator(int degree) {
if (degree < 1 || degree > 255)
throw new IllegalArgumentException("Degree out of range");
// Start with the monomial x^0
coefficients = new byte[degree];
coefficients[degree - 1] = 1;
// Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}),
// drop the highest term, and store the rest of the coefficients in order of descending powers.
// Note that r = 0x02, which is a generator element of this field GF(2^8/0x11D).
int root = 1;
for (int i = 0; i < degree; i++) {
// Multiply the current product by (x - r^i)
for (int j = 0; j < coefficients.length; j++) {
coefficients[j] = (byte)multiply(coefficients[j] & 0xFF, root);
if (j + 1 < coefficients.length)
coefficients[j] ^= coefficients[j + 1];
}
root = (root << 1) ^ ((root >>> 7) * 0x11D); // Multiply by 0x02 mod GF(2^8/0x11D)
}
}
/*-- Method --*/
/**
* Computes and returns the Reed-Solomon error correction codewords for the specified sequence of data codewords.
* The returned object is always a new byte array. This method does not alter this object's state (because it is immutable).
* @param data the sequence of data codewords
* @return the Reed-Solomon error correction codewords
* @throws NullPointerException if the data is {@code null}
*/
public byte[] getRemainder(byte[] data) {
if (data == null)
throw new NullPointerException();
// Compute the remainder by performing polynomial division
byte[] result = new byte[coefficients.length];
for (byte b : data) {
int factor = (b ^ result[0]) & 0xFF;
System.arraycopy(result, 1, result, 0, result.length - 1);
result[result.length - 1] = 0;
for (int j = 0; j < result.length; j++)
result[j] ^= multiply(coefficients[j] & 0xFF, factor);
}
return result;
}
/*-- Static function --*/
// Returns the product of the two given field elements modulo GF(2^8/0x11D). The arguments and result
// are unsigned 8-bit integers. This could be implemented as a lookup table of 256*256 entries of uint8.
private static int multiply(int x, int y) {
if ((x & 0xFF) != x || (y & 0xFF) != y)
throw new IllegalArgumentException("Byte out of range");
// Russian peasant multiplication
int z = 0;
for (int i = 7; i >= 0; i--) {
z = (z << 1) ^ ((z >>> 7) * 0x11D);
z ^= ((y >>> i) & 1) * x;
}
if ((z & 0xFF) != z)
throw new AssertionError();
return z;
}
}
}

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/*
* QR Code generator demo (Java)
*
* Run this command-line program with no arguments. The program creates/overwrites a bunch of
* PNG and SVG files in the current working directory to demonstrate the creation of QR Codes.
*
* Copyright (c) 2016 Project Nayuki
* https://www.nayuki.io/page/qr-code-generator-library
*
* (MIT License)
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
* - The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* - The Software is provided "as is", without warranty of any kind, express or
* implied, including but not limited to the warranties of merchantability,
* fitness for a particular purpose and noninfringement. In no event shall the
* authors or copyright holders be liable for any claim, damages or other
* liability, whether in an action of contract, tort or otherwise, arising from,
* out of or in connection with the Software or the use or other dealings in the
* Software.
*/
package io.nayuki.qrcodegen;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.List;
import javax.imageio.ImageIO;
public final class QrCodeGeneratorDemo {
// The main application program.
public static void main(String[] args) throws IOException {
doBasicDemo();
doVarietyDemo();
doSegmentDemo();
}
// Creates a single QR Code, then writes it to a PNG file and an SVG file.
private static void doBasicDemo() throws IOException {
String text = "Hello, world!"; // User-supplied Unicode text
QrCode.Ecc errCorLvl = QrCode.Ecc.LOW; // Error correction level
QrCode qr = QrCode.encodeText(text, errCorLvl); // Make the QR Code symbol
BufferedImage img = qr.toImage(10, 4); // Convert to bitmap image
File imgFile = new File("hello-world-QR.png"); // File path for output
ImageIO.write(img, "png", imgFile); // Write image to file
String svg = qr.toSvgString(4); // Convert to SVG XML code
try (Writer out = new OutputStreamWriter(
new FileOutputStream("hello-world-QR.svg"),
StandardCharsets.UTF_8)) {
out.write(svg); // Create/overwrite file and write SVG data
}
}
// Creates a variety of QR Codes that exercise different features of the library, and writes each one to file.
private static void doVarietyDemo() throws IOException {
QrCode qr;
// Project Nayuki URL
qr = QrCode.encodeText("https://www.nayuki.io/", QrCode.Ecc.HIGH);
qr = new QrCode(qr, 3); // Change mask, forcing to mask #3
writePng(qr.toImage(8, 6), "project-nayuki-QR.png");
// Numeric mode encoding (3.33 bits per digit)
qr = QrCode.encodeText("314159265358979323846264338327950288419716939937510", QrCode.Ecc.MEDIUM);
writePng(qr.toImage(13, 1), "pi-digits-QR.png");
// Alphanumeric mode encoding (5.5 bits per character)
qr = QrCode.encodeText("DOLLAR-AMOUNT:$39.87 PERCENTAGE:100.00% OPERATIONS:+-*/", QrCode.Ecc.HIGH);
writePng(qr.toImage(10, 2), "alphanumeric-QR.png");
// Unicode text as UTF-8, and different masks
qr = QrCode.encodeText("こんにちwa、世界！ αβγδ", QrCode.Ecc.QUARTILE);
writePng(new QrCode(qr, 0).toImage(10, 3), "unicode-mask0-QR.png");
writePng(new QrCode(qr, 1).toImage(10, 3), "unicode-mask1-QR.png");
writePng(new QrCode(qr, 5).toImage(10, 3), "unicode-mask5-QR.png");
writePng(new QrCode(qr, 7).toImage(10, 3), "unicode-mask7-QR.png");
// Moderately large QR Code using longer text (from Lewis Carroll's Alice in Wonderland)
qr = QrCode.encodeText("Alice was beginning to get very tired of sitting by her sister on the bank, "
+ "and of having nothing to do: once or twice she had peeped into the book her sister was reading, "
+ "but it had no pictures or conversations in it, 'and what is the use of a book,' thought Alice "
+ "'without pictures or conversations?' So she was considering in her own mind (as well as she could, "
+ "for the hot day made her feel very sleepy and stupid), whether the pleasure of making a "
+ "daisy-chain would be worth the trouble of getting up and picking the daisies, when suddenly "
+ "a White Rabbit with pink eyes ran close by her.",
QrCode.Ecc.HIGH);
writePng(qr.toImage(6, 10), "alice-wonderland-QR.png");
}
// Creates QR Codes with manually specified segments for better compactness.
private static void doSegmentDemo() throws IOException {
QrCode qr;
List<QrSegment> segs;
// Illustration "silver"
String silver0 = "THE SQUARE ROOT OF 2 IS 1.";
String silver1 = "41421356237309504880168872420969807856967187537694807317667973799";
qr = QrCode.encodeText(silver0 + silver1, QrCode.Ecc.LOW);
writePng(qr.toImage(10, 3), "sqrt2-monolithic-QR.png");
segs = Arrays.asList(
QrSegment.makeAlphanumeric(silver0),
QrSegment.makeNumeric(silver1));
qr = QrCode.encodeSegments(segs, QrCode.Ecc.LOW);
writePng(qr.toImage(10, 3), "sqrt2-segmented-QR.png");
// Illustration "golden"
String golden0 = "Golden ratio φ = 1.";
String golden1 = "6180339887498948482045868343656381177203091798057628621354486227052604628189024497072072041893911374";
String golden2 = "......";
qr = QrCode.encodeText(golden0 + golden1 + golden2, QrCode.Ecc.LOW);
writePng(qr.toImage(8, 5), "phi-monolithic-QR.png");
segs = Arrays.asList(
QrSegment.makeBytes(golden0.getBytes(StandardCharsets.UTF_8)),
QrSegment.makeNumeric(golden1),
QrSegment.makeAlphanumeric(golden2));
qr = QrCode.encodeSegments(segs, QrCode.Ecc.LOW);
writePng(qr.toImage(8, 5), "phi-segmented-QR.png");
}
// Helper function to reduce code duplication.
private static void writePng(BufferedImage img, String filepath) throws IOException {
ImageIO.write(img, "png", new File(filepath));
}
}

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/*
* QR Code generator library (Java)
*
* Copyright (c) 2016 Project Nayuki
* https://www.nayuki.io/page/qr-code-generator-library
*
* (MIT License)
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
* - The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* - The Software is provided "as is", without warranty of any kind, express or
* implied, including but not limited to the warranties of merchantability,
* fitness for a particular purpose and noninfringement. In no event shall the
* authors or copyright holders be liable for any claim, damages or other
* liability, whether in an action of contract, tort or otherwise, arising from,
* out of or in connection with the Software or the use or other dealings in the
* Software.
*/
package io.nayuki.qrcodegen;
import java.util.Arrays;
import java.util.regex.Pattern;
/**
* Represents a character string to be encoded in a QR Code symbol. Each segment has
* a mode, and a sequence of characters that is already encoded as a sequence of bits.
* Instances of this class are immutable.
* <p>This segment class imposes no length restrictions, but QR Codes have restrictions.
* Even in the most favorable conditions, a QR Code can only hold 7089 characters of data.
* Any segment longer than this is meaningless for the purpose of generating QR Codes.</p>
*/
public final class QrSegment {
/*---- Static factory functions ----*/
/**
* Returns a segment representing the specified binary data encoded in byte mode.
* @param data the binary data
* @return a segment containing the data
* @throws NullPointerException if the array is {@code null}
*/
public static QrSegment makeBytes(byte[] data) {
if (data == null)
throw new NullPointerException();
return new QrSegment(Mode.BYTE, data.length, data, data.length * 8);
}
/**
* Returns a segment representing the specified string of decimal digits encoded in numeric mode.
* @param digits a string consisting of digits from 0 to 9
* @return a segment containing the data
* @throws NullPointerException if the string is {@code null}
* @throws IllegalArgumentException if the string contains non-digit characters
*/
public static QrSegment makeNumeric(String digits) {
if (digits == null)
throw new NullPointerException();
if (!NUMERIC_REGEX.matcher(digits).matches())
throw new IllegalArgumentException("String contains non-numeric characters");
BitBuffer bb = new BitBuffer();
int i;
for (i = 0; i + 3 <= digits.length(); i += 3) // Process groups of 3
bb.appendBits(Integer.parseInt(digits.substring(i, i + 3)), 10);
int rem = digits.length() - i;
if (rem > 0) // 1 or 2 digits remaining
bb.appendBits(Integer.parseInt(digits.substring(i)), rem * 3 + 1);
return new QrSegment(Mode.NUMERIC, digits.length(), bb.getBytes(), bb.bitLength());
}
/**
* Returns a segment representing the specified text string encoded in alphanumeric mode. The characters allowed are:
* 0 to 9, A to Z (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
* @param text a string of text, with only certain characters allowed
* @return a segment containing the data
* @throws NullPointerException if the string is {@code null}
* @throws IllegalArgumentException if the string contains non-encodable characters
*/
public static QrSegment makeAlphanumeric(String text) {
if (text == null)
throw new NullPointerException();
if (!ALPHANUMERIC_REGEX.matcher(text).matches())
throw new IllegalArgumentException("String contains unencodable characters in alphanumeric mode");
BitBuffer bb = new BitBuffer();
int i;
for (i = 0; i + 2 <= text.length(); i += 2) { // Process groups of 2
int temp = ALPHANUMERIC_ENCODING_TABLE[text.charAt(i) - ' '] * 45;
temp += ALPHANUMERIC_ENCODING_TABLE[text.charAt(i + 1) - ' '];
bb.appendBits(temp, 11);
}
if (i < text.length()) // 1 character remaining
bb.appendBits(ALPHANUMERIC_ENCODING_TABLE[text.charAt(i) - ' '], 6);
return new QrSegment(Mode.ALPHANUMERIC, text.length(), bb.getBytes(), bb.bitLength());
}
/*---- Instance fields ----*/
/** The mode indicator for this segment. Never {@code null}. */
public final Mode mode;
/** The length of this segment's unencoded data, measured in characters. Always zero or positive. */
public final int numChars;
/** The bits of this segment packed into a byte array in big endian. Accessed through {@link getByte(int)}. Not {@code null}. */
private final byte[] data;
/** The length of this segment's encoded data, measured in bits. Satisfies 0 &le; {@code bitLength} &le; {@code data.length} &times; 8. */
public final int bitLength;
/*---- Constructor ----*/
/**
* Creates a new QR Code data segment with the specified parameters and data.
* @param md the mode, which is not {@code null}
* @param numCh the data length in characters, which is non-negative
* @param bitLen the data length in bits, which is non-negative
* @param b the bits packed into bytes, which is not {@code null}
* @throws NullPointerException if the mode or array is {@code null}
* @throws IllegalArgumentException if the character count or bit length are negative or invalid
*/
public QrSegment(Mode md, int numCh, byte[] b, int bitLen) {
if (md == null || b == null)
throw new NullPointerException();
if (numCh < 0 || bitLen < 0 || bitLen > b.length * 8L)
throw new IllegalArgumentException("Invalid value");
mode = md;
numChars = numCh;
data = Arrays.copyOf(b, (bitLen + 7) / 8); // Trim to precise length and also make defensive copy
bitLength = bitLen;
}
/*---- Method ----*/
/**
* Returns the data byte at the specified index.
* @param index the index to retrieve from, satisfying 0 &le; {@code index} &lt; ceil({@code bitLength} &divide; 8)
* @return the data byte at the specified index
* @throws IndexOutOfBoundsException if the index is out of bounds
*/
public byte getByte(int index) {
if (index < 0 || index > data.length)
throw new IndexOutOfBoundsException();
return data[index];
}
/*---- Constants ----*/
/** Can test whether a string is encodable in numeric mode (such as by using {@link #makeNumeric(String)}). */
public static final Pattern NUMERIC_REGEX = Pattern.compile("[0-9]*");
/** Can test whether a string is encodable in alphanumeric mode (such as by using {@link #makeAlphanumeric(String)}). */
public static final Pattern ALPHANUMERIC_REGEX = Pattern.compile("[A-Z0-9 $%*+./:-]*");
private static final byte[] ALPHANUMERIC_ENCODING_TABLE = {
// SP, !, ", #, $, %, &, ', (, ), *, +, ,, -, ., /, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, :, ;, <, =, >, ?, @, // ASCII codes 32 to 64
36, -1, -1, -1, 37, 38, -1, -1, -1, -1, 39, 40, -1, 41, 42, 43, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 44, -1, -1, -1, -1, -1, -1, // Array indices 0 to 32
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, // Array indices 33 to 58
// A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, // ASCII codes 65 to 90
};
/*---- Public helper enumeration ----*/
/**
* The mode field of a segment. Immutable. Provides methods to retrieve closely related values.
*/
public enum Mode {
// Constants.
NUMERIC (0x1, 10, 12, 14),
ALPHANUMERIC(0x2, 9, 11, 13),
BYTE (0x4, 8, 16, 16),
KANJI (0x8, 8, 10, 12);
/*-- Fields --*/
/** An unsigned 4-bit integer value (range 0 to 15) representing the mode indicator bits for this mode object. */
public final int modeBits;
private final int[] numBitsCharCount;
// Constructor.
private Mode(int mode, int... ccbits) {
this.modeBits = mode;
numBitsCharCount = ccbits;
}
/*-- Method --*/
/**
* Returns the bit width of the segment character count field for this mode object at the specified version number.
* @param ver the version number, which is between 1 to 40, inclusive
* @return the number of bits for the character count, which is between 8 to 16, inclusive
* @throws IllegalArgumentException if the version number is out of range
*/
public int numCharCountBits(int ver) {
if ( 1 <= ver && ver <= 9) return numBitsCharCount[0];
else if (10 <= ver && ver <= 26) return numBitsCharCount[1];
else if (27 <= ver && ver <= 40) return numBitsCharCount[2];
else throw new IllegalArgumentException("Version number out of range");
}
}
}

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/*
* QR Code generator demo (JavaScript)
*
* Copyright (c) 2016 Project Nayuki
* https://www.nayuki.io/page/qr-code-generator-library
*
* (MIT License)
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
* - The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* - The Software is provided "as is", without warranty of any kind, express or
* implied, including but not limited to the warranties of merchantability,
* fitness for a particular purpose and noninfringement. In no event shall the
* authors or copyright holders be liable for any claim, damages or other
* liability, whether in an action of contract, tort or otherwise, arising from,
* out of or in connection with the Software or the use or other dealings in the
* Software.
*/
"use strict";
function redrawQrCode() {
// Get error correction level
var ecl;
if (document.getElementById("errcorlvl-medium").checked)
ecl = qrcodegen.QrCode.Ecc.MEDIUM;
else if (document.getElementById("errcorlvl-quartile").checked)
ecl = qrcodegen.QrCode.Ecc.QUARTILE;
else if (document.getElementById("errcorlvl-high").checked)
ecl = qrcodegen.QrCode.Ecc.HIGH;
else // In case no radio button is depressed
ecl = qrcodegen.QrCode.Ecc.LOW;
// Get text and compute QR Code
var text = document.getElementById("text-input").value;
var qr = qrcodegen.encodeText(text, ecl);
// Get scale and border
var scale = parseInt(document.getElementById("scale-input").value, 10);
var border = parseInt(document.getElementById("border-input").value, 10);
if (scale <= 0 || border < 0 || scale > 30 || border > 100)
return;
// Draw QR Code onto canvas
var canvas = document.getElementById("qrcode-canvas");
var width = (qr.getSize() + border * 2) * scale;
if (canvas.width != width) {
canvas.width = width;
canvas.height = width;
}
var ctx = canvas.getContext("2d");
for (var y = -border; y < qr.getSize() + border; y++) {
for (var x = -border; x < qr.getSize() + border; x++) {
ctx.fillStyle = qr.getModule(x, y) == 1 ? "#000000" : "#FFFFFF";
ctx.fillRect((x + border) * scale, (y + border) * scale, scale, scale);
}
}
// Show statistics
var stats = "QR Code version = " + qr.getVersion() + ", ";
stats += "mask pattern = " + qr.getMask() + ", ";
stats += "character count = " + countUnicodeChars(text) + ",\n";
stats += "encoding mode = ";
var seg = qrcodegen.encodeTextToSegment(text);
if (seg.getMode() == qrcodegen.QrSegment.Mode.NUMERIC)
stats += "numeric";
else if (seg.getMode() == qrcodegen.QrSegment.Mode.ALPHANUMERIC)
stats += "alphanumeric";
else if (seg.getMode() == qrcodegen.QrSegment.Mode.BYTE)
stats += "byte";
else if (seg.getMode() == qrcodegen.QrSegment.Mode.BYTE)
stats += "kanji";
else
stats += "unknown";
stats += ", data bits = " + (4 + seg.getMode().numCharCountBits(qr.getVersion()) + seg.getBits().length) + ".";
var elem = document.getElementById("statistics-output");
while (elem.firstChild != null)
elem.removeChild(elem.firstChild);
elem.appendChild(document.createTextNode(stats));
}
function countUnicodeChars(str) {
var result = 0;
for (var i = 0; i < str.length; i++, result++) {
var c = str.charCodeAt(i);
if (c < 0xD800 || c >= 0xE000)
continue;
else if (0xD800 <= c && c < 0xDC00) { // High surrogate
i++;
var d = str.charCodeAt(i);
if (0xDC00 <= d && d < 0xE000) // Low surrogate
continue;
}
throw "Invalid UTF-16 string";
}
return result;
}
redrawQrCode();

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<!--
- QR Code generator library (C++)
-
- Copyright (c) 2016 Project Nayuki
- https://www.nayuki.io/page/qr-code-generator-library
-
- (MIT License)
- Permission is hereby granted, free of charge, to any person obtaining a copy of
- this software and associated documentation files (the "Software"), to deal in
- the Software without restriction, including without limitation the rights to
- use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
- the Software, and to permit persons to whom the Software is furnished to do so,
- subject to the following conditions:
- * The above copyright notice and this permission notice shall be included in
- all copies or substantial portions of the Software.
- * The Software is provided "as is", without warranty of any kind, express or
- implied, including but not limited to the warranties of merchantability,
- fitness for a particular purpose and noninfringement. In no event shall the
- authors or copyright holders be liable for any claim, damages or other
- liability, whether in an action of contract, tort or otherwise, arising from,
- out of or in connection with the Software or the use or other dealings in the
- Software.
-->
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>QR Code generator library demo (JavaScript)</title>
<style type="text/css">
td {
vertical-align: top;
}
</style>
</head>
<body>
<h1>QR Code generator demo library (JavaScript)</h1>
<form action="#" method="get" onsubmit="return false;">
<table class="noborder" style="width:100%">
<tbody>
<tr>
<td>Text string:</td>
<td style="width:100%"><textarea placeholder="Enter your text to be put into the QR Code" id="text-input" style="width:100%; max-width:30em; height:5em; font-family:inherit" oninput="redrawQrCode();"></textarea></td>
</tr>
<tr>
<td>Error&#xA0;correction:</td>
<td>
<input type="radio" name="errcorlvl" id="errcorlvl-low" onchange="redrawQrCode();" checked="checked"><label for="errcorlvl-low">Low</label>
<input type="radio" name="errcorlvl" id="errcorlvl-medium" onchange="redrawQrCode();"><label for="errcorlvl-medium">Medium</label>
<input type="radio" name="errcorlvl" id="errcorlvl-quartile" onchange="redrawQrCode();"><label for="errcorlvl-quartile">Quartile</label>
<input type="radio" name="errcorlvl" id="errcorlvl-high" onchange="redrawQrCode();"><label for="errcorlvl-high">High</label>
</td>
</tr>
<tr>
<td>Scale:</td>
<td><input type="number" value="8" min="1" max="30" step="1" id="scale-input" style="width:4em" oninput="redrawQrCode();"> pixels per module</td>
</tr>
<tr>
<td>Border:</td>
<td><input type="number" value="4" min="0" max="100" step="1" id="border-input" style="width:4em" oninput="redrawQrCode();"> modules</td>
</tr>
<tr>
<td>Statistics:</td>
<td id="statistics-output" style="white-space:pre"></td>
</tr>
<tr>
<td>QR&#xA0;Code:</td>
<td>
<canvas id="qrcode-canvas" style="padding:1em; background-color:#E8E8E8"></canvas>
</td>
</tr>
</tbody>
</table>
</form>
<script type="application/javascript" src="qrcodegen.js"></script>
<script type="application/javascript" src="qrcodegen-demo.js"></script>
<hr>
<p>Copyright © 2016 Project Nayuki – <a href="https://www.nayuki.io/page/qr-code-generator-library">https://www.nayuki.io/page/qr-code-generator-library</a></p>
</body>
</html>

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/*
* QR Code generator library (JavaScript)
*
* Copyright (c) 2016 Project Nayuki
* https://www.nayuki.io/page/qr-code-generator-library
*
* (MIT License)
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
* - The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* - The Software is provided "as is", without warranty of any kind, express or
* implied, including but not limited to the warranties of merchantability,
* fitness for a particular purpose and noninfringement. In no event shall the
* authors or copyright holders be liable for any claim, damages or other
* liability, whether in an action of contract, tort or otherwise, arising from,
* out of or in connection with the Software or the use or other dealings in the
* Software.
*/
"use strict";
/*
* Module "qrcodegen". Public members inside this namespace:
* - Function encodeText(str text, Ecc ecl) -> QrCode
* - Function encodeTextToSegment(str text) -> QrSegment
* - Function encodeBinary(list<int> data, Ecc ecl) -> QrCode
* - Function encodeSegments(list<QrSegment> segs, Ecc ecl) -> QrCode
* - Class QrCode:
* - Constructor QrCode(QrCode qr, int mask)
* - Constructor QrCode(list<int> bytes, int mask, int version, Ecc ecl)
* - Method getVersion() -> int
* - Method getSize() -> int
* - Method getErrorCorrectionLevel() -> Ecc
* - Method getMask() -> int
* - Method getModule(int x, int y) -> int
* - Method isFunctionModule(int x, int y) -> bool
* - Method toSvgString(int border) -> str
* - Enum Ecc:
* - Constants LOW, MEDIUM, QUARTILE, HIGH
* - Fields int ordinal, formatBits
* - Class QrSegment:
* - Function makeBytes(list<int> data) -> QrSegment
* - Function makeNumeric(str data) -> QrSegment
* - Function makeAlphanumeric(str data) -> QrSegment
* - Constructor QrSegment(Mode mode, int numChars, list<int> bitData)
* - Method getMode() -> Mode
* - Method getNumChars() -> int
* - Method getBits() -> list<int>
* - Enum Mode:
* - Constants NUMERIC, ALPHANUMERIC, BYTE, KANJI
* - Method getModeBits() -> int
* - Method numCharCountBits(int ver) -> int
*/
var qrcodegen = new function() {
/*---- Public static factory functions for QrCode ----*/
/*
* Returns a QR Code symbol representing the given Unicode text string at the given error correction level.
* As a conservative upper bound, this function is guaranteed to succeed for strings that have 738 or fewer Unicode
* code points (not UTF-16 code units). The smallest possible QR Code version is automatically chosen for the output.
*/
this.encodeText = function(text, ecl) {
var seg = this.encodeTextToSegment(text);
return this.encodeSegments([seg], ecl);
};
/*
* Returns a single QR segment representing the given Unicode text string.
*/
this.encodeTextToSegment = function(text) {
// Select the most efficient segment encoding automatically
if (QrSegment.NUMERIC_REGEX.test(text))
return this.QrSegment.makeNumeric(text);
else if (QrSegment.ALPHANUMERIC_REGEX.test(text))
return this.QrSegment.makeAlphanumeric(text);
else
return this.QrSegment.makeBytes(toUtf8ByteArray(text));
};
/*
* Returns a QR Code symbol representing the given binary data string at the given error correction level.
* This function always encodes using the binary segment mode, not any text mode. The maximum number of
* bytes allowed is 2953. The smallest possible QR Code version is automatically chosen for the output.
*/
this.encodeBinary = function(data, ecl) {
var seg = this.QrSegment.makeBytes(data);
return this.encodeSegments([seg], ecl);
};
/*
* Returns a QR Code symbol representing the given data segments at the given error
* correction level. The smallest possible QR Code version is automatically chosen for the output.
* This function allows the user to create a custom sequence of segments that switches
* between modes (such as alphanumeric and binary) to encode text more efficiently. This
* function is considered to be lower level than simply encoding text or binary data.
*/
this.encodeSegments = function(segs, ecl) {
// Find the minimal version number to use
var version, dataCapacityBits;
outer:
for (version = 1; ; version++) { // Increment until the data fits in the QR Code
if (version > 40) // All versions could not fit the given data
throw "Data too long";
dataCapacityBits = QrCode.getNumDataCodewords(version, ecl) * 8; // Number of data bits available
// Calculate the total number of bits needed at this version number
// to encode all the segments (i.e. segment metadata and payloads)
var dataUsedBits = 0;
for (var i = 0; i < segs.length; i++) {
var seg = segs[i];
if (seg.numChars < 0)
throw "Assertion error";
var ccbits = seg.getMode().numCharCountBits(version);
if (seg.getNumChars() >= (1 << ccbits)) {
// Segment length value doesn't fit in the length field's bit-width, so fail immediately
continue outer;
}
dataUsedBits += 4 + ccbits + seg.getBits().length;
}
if (dataUsedBits <= dataCapacityBits)
break; // This version number is found to be suitable
}
// Create the data bit string by concatenating all segments
var bb = new BitBuffer();
segs.forEach(function(seg) {
bb.appendBits(seg.getMode().getModeBits(), 4);
bb.appendBits(seg.getNumChars(), seg.getMode().numCharCountBits(version));
bb.appendData(seg);
});
// Add terminator and pad up to a byte if applicable
bb.appendBits(0, Math.min(4, dataCapacityBits - bb.bitLength()));
bb.appendBits(0, (8 - bb.bitLength() % 8) % 8);
// Pad with alternate bytes until data capacity is reached
for (var padByte = 0xEC; bb.bitLength() < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
bb.appendBits(padByte, 8);
if (bb.bitLength() % 8 != 0)
throw "Assertion error";
// Create the QR Code symbol
return new this.QrCode(bb.getBytes(), -1, version, ecl);
};
/*
* A class that represents an immutable square grid of black and white cells for a QR Code symbol,
* with associated static functions to create a QR Code from user-supplied textual or binary data.
* This class covers the QR Code model 2 specification, supporting all versions (sizes)
* from 1 to 40, all 4 error correction levels, and only 3 character encoding modes.
*
* This constructor can be called in one of two ways:
* - new QrCode(bytes, mask, version, errCorLvl):
* Creates a new QR Code symbol with the given version number, error correction level, binary data array,
* and mask number. This cumbersome constructor can be invoked directly by the user, but is considered
* to be even lower level than qrcodegen.encodeSegments().
* - new QrCode(qr, mask):
* Creates a new QR Code symbol based on the given existing object, but with a potentially different
* mask pattern. The version, error correction level, codewords, etc. of the newly created object are
* all identical to the argument object; only the mask may differ.
* In both cases, mask = -1 is for automatic choice or 0 to 7 for fixed choice.
*/
this.QrCode = function(initData, mask, version, errCorLvl) {
/*-- Constructor --*/
// Handle simple scalar fields
if (mask < -1 || mask > 7)
throw "Mask value out of range";
var size;
if (initData instanceof Array) {
if (version < 1 || version > 40)
throw "Version value out of range";
size = version * 4 + 17;
} else if (initData instanceof qrcodegen.QrCode) {
version = initData.getVersion();
size = initData.getSize();
errCorLvl = initData.getErrorCorrectionLevel();
} else
throw "Invalid initial data";
// Initialize both grids to be size*size arrays of Boolean false
var row = [];
for (var i = 0; i < size; i++)
row.push(false);
var modules = [];
var isFunction = [];
for (var i = 0; i < size; i++) {
modules.push(row.slice());
isFunction.push(row.slice());
}
// Handle grid fields
if (initData instanceof Array) {
// Draw function patterns, draw all codewords, do masking
drawFunctionPatterns();
var allCodewords = appendErrorCorrection(initData);
drawCodewords(allCodewords);
} else if (initData instanceof qrcodegen.QrCode) {
for (var y = 0; y < size; y++) {
for (var x = 0; x < size; x++) {
modules[y][x] = initData.getModule(x, y) == 1;
isFunction[y][x] = initData.isFunctionModule(x, y);
}
}
applyMask(initData.getMask()); // Undo old mask
} else
throw "Invalid initial data";
// Handle masking
if (mask == -1) { // Automatically choose best mask
var minPenalty = Infinity;
for (var i = 0; i < 8; i++) {
drawFormatBits(i);
applyMask(i);
var penalty = getPenaltyScore();
if (penalty < minPenalty) {
mask = i;
minPenalty = penalty;
}
applyMask(i); // Undoes the mask due to XOR
}
}
if (mask < 0 || mask > 7)
throw "Assertion error";
drawFormatBits(mask); // Overwrite old format bits
applyMask(mask); // Apply the final choice of mask
/*-- Accessor methods --*/
// Returns this QR Code symbol's version number, which is always between 1 and 40 (inclusive).
this.getVersion = function() {
return version;
};
// Returns the width and height of this QR Code symbol, measured in modules.
// Always equal to version * 4 + 17, in the range 21 to 177.
this.getSize = function() {
return size;
};
// Returns the error correction level used in this QR Code symbol.
this.getErrorCorrectionLevel = function() {
return errCorLvl;
};
// Returns the mask pattern used in this QR Code symbol, in the range 0 to 7 (i.e. unsigned 3-bit integer).
// Note that even if a constructor was called with automatic masking requested
// (mask = -1), the resulting object will still have a mask value between 0 and 7.
this.getMask = function() {
return mask;
};
// Returns the color of the module (pixel) at the given coordinates, which is either 0 for white or 1 for black. The top
// left corner has the coordinates (x=0, y=0). If the given coordinates are out of bounds, then 0 (white) is returned.
this.getModule = function(x, y) {
if (x < 0 || x >= size || y < 0 || y >= size)
return 0; // Infinite white border
else
return modules[y][x] ? 1 : 0;
};
// Tests whether the module at the given coordinates is a function module (true) or not (false). The top left
// corner has the coordinates (x=0, y=0). If the given coordinates are out of bounds, then false is returned.
this.isFunctionModule = function(x, y) {
if (x < 0 || x >= size || y < 0 || y >= size)
return false; // Infinite border
else
return isFunction[y][x];
};
/*-- Public instance methods --*/
// Based on the given number of border modules to add as padding, this returns a
// string whose contents represents an SVG XML file that depicts this QR Code symbol.
this.toSvgString = function(border) {
if (border < 0)
throw "Border must be non-negative";
var result = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
result += "<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\" \"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\">\n";
result += "<svg xmlns=\"http://www.w3.org/2000/svg\" version=\"1.1\" viewBox=\"0 0 " + (size + border * 2) + " " + (size + border * 2) + "\">\n";
result += "\t<path d=\"";
var head = true;
for (var y = -border; y < size + border; y++) {
for (var x = -border; x < size + border; x++) {
if (this.getModule(x, y) == 1) {
if (head)
head = false;
else
result += " ";
result += "M" + (x + border) + "," + (y + border) + "h1v1h-1z";
}
}
}
result += "\" fill=\"#000000\" stroke-width=\"0\"/>\n";
result += "</svg>\n";
return result;
};
/*-- Private helper methods for constructor: Drawing function modules --*/
function drawFunctionPatterns() {
// Draw the horizontal and vertical timing patterns
for (var i = 0; i < size; i++) {
setFunctionModule(6, i, i % 2 == 0);
setFunctionModule(i, 6, i % 2 == 0);
}
// Draw 3 finder patterns (all corners except bottom right; overwrites some timing modules)
drawFinderPattern(3, 3);
drawFinderPattern(size - 4, 3);
drawFinderPattern(3, size - 4);
// Draw the numerous alignment patterns
var alignPatPos = QrCode.getAlignmentPatternPositions(version);
var numAlign = alignPatPos.length;
for (var i = 0; i < numAlign; i++) {
for (var j = 0; j < numAlign; j++) {
if (i == 0 && j == 0 || i == 0 && j == numAlign - 1 || i == numAlign - 1 && j == 0)
continue; // Skip the three finder corners
else
drawAlignmentPattern(alignPatPos[i], alignPatPos[j]);
}
}
// Draw configuration data
drawFormatBits(0); // Dummy mask value; overwritten later in the constructor
drawVersion();
}
// Draws two copies of the format bits (with its own error correction code)
// based on this object's error correction level and mask fields.
function drawFormatBits(mask) {
// Calculate error correction code and pack bits
var data = errCorLvl.formatBits << 3 | mask; // errCorrLvl is uint2, mask is uint3
var rem = data;
for (var i = 0; i < 10; i++)
rem = (rem << 1) ^ ((rem >>> 9) * 0x537);
data = data << 10 | rem;
data ^= 0x5412; // uint15
if ((data & ((1 << 15) - 1)) != data)
throw "Assertion error";
// Draw first copy
for (var i = 0; i <= 5; i++)
setFunctionModule(8, i, ((data >>> i) & 1) != 0);
setFunctionModule(8, 7, ((data >>> 6) & 1) != 0);
setFunctionModule(8, 8, ((data >>> 7) & 1) != 0);
setFunctionModule(7, 8, ((data >>> 8) & 1) != 0);
for (var i = 9; i < 15; i++)
setFunctionModule(14 - i, 8, ((data >>> i) & 1) != 0);
// Draw second copy
for (var i = 0; i <= 7; i++)
setFunctionModule(size - 1 - i, 8, ((data >>> i) & 1) != 0);
for (var i = 8; i < 15; i++)
setFunctionModule(8, size - 15 + i, ((data >>> i) & 1) != 0);
setFunctionModule(8, size - 8, true);
}
// Draws two copies of the version bits (with its own error correction code),
// based on this object's version field (which only has an effect for 7 <= version <= 40).
function drawVersion() {
if (version < 7)
return;
// Calculate error correction code and pack bits
var rem = version; // version is uint6, in the range [7, 40]
for (var i = 0; i < 12; i++)
rem = (rem << 1) ^ ((rem >>> 11) * 0x1F25);
var data = version << 12 | rem; // uint18
if ((data & ((1 << 18) - 1)) != data)
throw "Assertion error";
// Draw two copies
for (var i = 0; i < 18; i++) {
var bit = ((data >>> i) & 1) != 0;
var a = size - 11 + i % 3;
var b = Math.floor(i / 3);
setFunctionModule(a, b, bit);
setFunctionModule(b, a, bit);
}
}
// Draws a 9*9 finder pattern including the border separator, with the center module at (x, y).
function drawFinderPattern(x, y) {
for (var i = -4; i <= 4; i++) {
for (var j = -4; j <= 4; j++) {
var dist = Math.max(Math.abs(i), Math.abs(j)); // Chebyshev/infinity norm
var xx = x + j;
var yy = y + i;
if (0 <= xx && xx < size && 0 <= yy && yy < size)
setFunctionModule(xx, yy, dist != 2 && dist != 4);
}
}
}
// Draws a 5*5 alignment pattern, with the center module at (x, y).
function drawAlignmentPattern(x, y) {
for (var i = -2; i <= 2; i++) {
for (var j = -2; j <= 2; j++)
setFunctionModule(x + j, y + i, Math.max(Math.abs(i), Math.abs(j)) != 1);
}
}
// Sets the color of a module and marks it as a function module.
// Only used by the constructor. Coordinates must be in range.
function setFunctionModule(x, y, isBlack) {
modules[y][x] = isBlack;
isFunction[y][x] = true;
}
/*---- Private helper methods for constructor: Codewords and masking ----*/
// Returns a new byte string representing the given data with the appropriate error correction
// codewords appended to it, based on this object's version and error correction level.
function appendErrorCorrection(data) {
if (data.length != QrCode.getNumDataCodewords(version, errCorLvl))
throw "Invalid argument";
var numBlocks = QrCode.NUM_ERROR_CORRECTION_BLOCKS[errCorLvl.ordinal][version];
var numEcc = QrCode.NUM_ERROR_CORRECTION_CODEWORDS[errCorLvl.ordinal][version];
if (numEcc % numBlocks != 0)
throw "Assertion error";
var eccLen = Math.floor(numEcc / numBlocks);
var numShortBlocks = numBlocks - Math.floor(QrCode.getNumRawDataModules(version) / 8) % numBlocks;
var shortBlockLen = Math.floor(QrCode.getNumRawDataModules(version) / (numBlocks * 8));
var blocks = [];
var rs = new ReedSolomonGenerator(eccLen);
for (var i = 0, k = 0; i < numBlocks; i++) {
var dat = data.slice(k, k + shortBlockLen - eccLen + (i < numShortBlocks ? 0 : 1));
k += dat.length;
var ecc = rs.getRemainder(dat);
if (i < numShortBlocks)
dat.push(0);
ecc.forEach(function(b) {
dat.push(b);
});
blocks.push(dat);
}
var result = [];
for (var i = 0; i < blocks[0].length; i++) {
for (var j = 0; j < blocks.length; j++) {
if (i != shortBlockLen - eccLen || j >= numShortBlocks)
result.push(blocks[j][i]);
}
}
if (result.length != Math.floor(QrCode.getNumRawDataModules(version) / 8))
throw "Assertion error";
return result;
}
// Draws the given sequence of 8-bit codewords (data and error correction) onto the entire
// data area of this QR Code symbol. Function modules need to be marked off before this is called.
function drawCodewords(data) {
if (data.length != Math.floor(QrCode.getNumRawDataModules(version) / 8))
throw "Invalid argument";
var i = 0; // Bit index into the data
// Do the funny zigzag scan
for (var right = size - 1; right >= 1; right -= 2) { // Index of right column in each column pair
if (right == 6)
right = 5;
for (var vert = 0; vert < size; vert++) { // Vertical counter
for (var j = 0; j < 2; j++) {
var x = right - j; // Actual x coordinate
var upwards = ((right & 2) == 0) ^ (x < 6);
var y = upwards ? size - 1 - vert : vert; // Actual y coordinate
if (!isFunction[y][x] && i < data.length * 8) {
modules[y][x] = (data[i >>> 3] >>> (7 - (i & 7)) & 1) != 0;
i++;
}
}
}
}
if (i != data.length * 8)
throw "Assertion error";
}
// XORs the data modules in this QR Code with the given mask pattern. Due to XOR's mathematical
// properties, calling applyMask(m) twice with the same value is equivalent to no change at all.
// This means it is possible to apply a mask, undo it, and try another mask. Note that a final
// well-formed QR Code symbol needs exactly one mask applied (not zero, not two, etc.).
function applyMask(mask) {
if (mask < 0 || mask > 7)
throw "Mask value out of range";
for (var y = 0; y < size; y++) {
for (var x = 0; x < size; x++) {
var invert;
switch (mask) {
case 0: invert = (x + y) % 2 == 0; break;
case 1: invert = y % 2 == 0; break;
case 2: invert = x % 3 == 0; break;
case 3: invert = (x + y) % 3 == 0; break;
case 4: invert = (Math.floor(x / 3) + Math.floor(y / 2)) % 2 == 0; break;
case 5: invert = x * y % 2 + x * y % 3 == 0; break;
case 6: invert = (x * y % 2 + x * y % 3) % 2 == 0; break;
case 7: invert = ((x + y) % 2 + x * y % 3) % 2 == 0; break;
default: throw "Assertion error";
}
modules[y][x] ^= invert & !isFunction[y][x];
}
}
}
// Calculates and returns the penalty score based on state of this QR Code's current modules.
// This is used by the automatic mask choice algorithm to find the mask pattern that yields the lowest score.
function getPenaltyScore() {
var result = 0;
// Adjacent modules in row having same color
for (var y = 0; y < size; y++) {
var colorX = modules[y][0];
for (var x = 1, runX = 1; x < size; x++) {
if (modules[y][x] != colorX) {
colorX = modules[y][x];
runX = 1;
} else {
runX++;
if (runX == 5)
result += QrCode.PENALTY_N1;
else if (runX > 5)
result++;
}
}
}
// Adjacent modules in column having same color
for (var x = 0; x < size; x++) {
var colorY = modules[0][x];
for (var y = 1, runY = 1; y < size; y++) {
if (modules[y][x] != colorY) {
colorY = modules[y][x];
runY = 1;
} else {
runY++;
if (runY == 5)
result += QrCode.PENALTY_N1;
else if (runY > 5)
result++;
}
}
}
// 2*2 blocks of modules having same color
for (var y = 0; y < size - 1; y++) {
for (var x = 0; x < size - 1; x++) {
var color = modules[y][x];
if ( color == modules[y][x + 1] &&
color == modules[y + 1][x] &&
color == modules[y + 1][x + 1])
result += QrCode.PENALTY_N2;
}
}
// Finder-like pattern in rows
for (var y = 0; y < size; y++) {
for (var x = 0, bits = 0; x < size; x++) {
bits = ((bits << 1) & 0x7FF) | (modules[y][x] ? 1 : 0);
if (x >= 10 && (bits == 0x05D || bits == 0x5D0)) // Needs 11 bits accumulated
result += QrCode.PENALTY_N3;
}
}
// Finder-like pattern in columns
for (var x = 0; x < size; x++) {
for (var y = 0, bits = 0; y < size; y++) {
bits = ((bits << 1) & 0x7FF) | (modules[y][x] ? 1 : 0);
if (y >= 10 && (bits == 0x05D || bits == 0x5D0)) // Needs 11 bits accumulated
result += QrCode.PENALTY_N3;
}
}
// Balance of black and white modules
var black = 0;
modules.forEach(function(row) {
row.forEach(function(color) {
if (color)
black++;
});
});
var total = size * size;
// Find smallest k such that (45-5k)% <= dark/total <= (55+5k)%
for (var k = 0; black*20 < (9-k)*total || black*20 > (11+k)*total; k++)
result += QrCode.PENALTY_N4;
return result;
}
};
/*---- Private static helper functions ----*/
var QrCode = {}; // Private object to assign properties to
// Returns a set of positions of the alignment patterns in ascending order. These positions are
// used on both the x and y axes. Each value in the resulting array is in the range [0, 177).
// This stateless pure function could be implemented as table of 40 variable-length lists of unsigned bytes.
QrCode.getAlignmentPatternPositions = function(ver) {
if (ver < 1 || ver > 40)
throw "Version number out of range";
else if (ver == 1)
return [];
else {
var size = ver * 4 + 17;
var numAlign = Math.floor(ver / 7) + 2;
var step;
if (ver != 32)
step = Math.ceil((size - 13) / (2 * numAlign - 2)) * 2;
else // C-C-C-Combo breaker!
step = 26;
var result = [];
for (var i = numAlign - 1, pos = size - 7; i >= 1; i--, pos -= step)
result.push(pos);
result.push(6);
result.reverse();
return result;
}
};
// Returns the number of raw data modules (bits) available at the given version number.
// These data modules are used for both user data codewords and error correction codewords.
// This stateless pure function could be implemented as a 40-entry lookup table.
QrCode.getNumRawDataModules = function(ver) {
if (ver < 1 || ver > 40)
throw "Version number out of range";
var result = (16 * ver + 128) * ver + 64;
if (ver >= 2) {
var numAlign = Math.floor(ver / 7) + 2;
result -= (25 * numAlign - 10) * numAlign - 55;
if (ver >= 7)
result -= 18 * 2; // Subtract version information
}
return result;
};
// Returns the number of 8-bit data (i.e. not error correction) codewords contained in any
// QR Code of the given version number and error correction level, with remainder bits discarded.
// This stateless pure function could be implemented as a (40*4)-cell lookup table.
QrCode.getNumDataCodewords = function(ver, ecl) {
return Math.floor(QrCode.getNumRawDataModules(ver) / 8) - QrCode.NUM_ERROR_CORRECTION_CODEWORDS[ecl.ordinal][ver];
};
/*---- Tables of constants ----*/
// For use in getPenaltyScore(), when evaluating which mask is best.
QrCode.PENALTY_N1 = 3;
QrCode.PENALTY_N2 = 3;
QrCode.PENALTY_N3 = 40;
QrCode.PENALTY_N4 = 10;
QrCode.NUM_ERROR_CORRECTION_CODEWORDS = [
// Version: (note that index 0 is for padding, and is set to an illegal value)
// 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 Error correction level
[null, 7, 10, 15, 20, 26, 36, 40, 48, 60, 72, 80, 96, 104, 120, 132, 144, 168, 180, 196, 224, 224, 252, 270, 300, 312, 336, 360, 390, 420, 450, 480, 510, 540, 570, 570, 600, 630, 660, 720, 750], // Low
[null, 10, 16, 26, 36, 48, 64, 72, 88, 110, 130, 150, 176, 198, 216, 240, 280, 308, 338, 364, 416, 442, 476, 504, 560, 588, 644, 700, 728, 784, 812, 868, 924, 980, 1036, 1064, 1120, 1204, 1260, 1316, 1372], // Medium
[null, 13, 22, 36, 52, 72, 96, 108, 132, 160, 192, 224, 260, 288, 320, 360, 408, 448, 504, 546, 600, 644, 690, 750, 810, 870, 952, 1020, 1050, 1140, 1200, 1290, 1350, 1440, 1530, 1590, 1680, 1770, 1860, 1950, 2040], // Quartile
[null, 17, 28, 44, 64, 88, 112, 130, 156, 192, 224, 264, 308, 352, 384, 432, 480, 532, 588, 650, 700, 750, 816, 900, 960, 1050, 1110, 1200, 1260, 1350, 1440, 1530, 1620, 1710, 1800, 1890, 1980, 2100, 2220, 2310, 2430], // High
];
QrCode.NUM_ERROR_CORRECTION_BLOCKS = [
// Version: (note that index 0 is for padding, and is set to an illegal value)
// 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 Error correction level
[null, 1, 1, 1, 1, 1, 2, 2, 2, 2, 4, 4, 4, 4, 4, 6, 6, 6, 6, 7, 8, 8, 9, 9, 10, 12, 12, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 21, 22, 24, 25], // Low
[null, 1, 1, 1, 2, 2, 4, 4, 4, 5, 5, 5, 8, 9, 9, 10, 10, 11, 13, 14, 16, 17, 17, 18, 20, 21, 23, 25, 26, 28, 29, 31, 33, 35, 37, 38, 40, 43, 45, 47, 49], // Medium
[null, 1, 1, 2, 2, 4, 4, 6, 6, 8, 8, 8, 10, 12, 16, 12, 17, 16, 18, 21, 20, 23, 23, 25, 27, 29, 34, 34, 35, 38, 40, 43, 45, 48, 51, 53, 56, 59, 62, 65, 68], // Quartile
[null, 1, 1, 2, 4, 4, 4, 5, 6, 8, 8, 11, 11, 16, 16, 18, 16, 19, 21, 25, 25, 25, 34, 30, 32, 35, 37, 40, 42, 45, 48, 51, 54, 57, 60, 63, 66, 70, 74, 77, 81], // High
];
/*
* A public helper enumeration that represents the error correction level used in a QR Code symbol.
* The fields 'ordinal' and 'formatBits' are in the range 0 to 3 (unsigned 2-bit integer).
*/
this.QrCode.Ecc = {
// Constants declared in ascending order of error protection
LOW : {ordinal: 0, formatBits: 1},
MEDIUM : {ordinal: 1, formatBits: 0},
QUARTILE: {ordinal: 2, formatBits: 3},
HIGH : {ordinal: 3, formatBits: 2},
};
/*
* A public class that represents a character string to be encoded in a QR Code symbol.
* Each segment has a mode, and a sequence of characters that is already encoded as
* a sequence of bits. Instances of this class are immutable.
* This segment class imposes no length restrictions, but QR Codes have restrictions.
* Even in the most favorable conditions, a QR Code can only hold 7089 characters of data.
* Any segment longer than this is meaningless for the purpose of generating QR Codes.
*/
this.QrSegment = function(mode, numChars, bitData) {
/*-- Accessor methods --*/
this.getMode = function() {
return mode;
};
this.getNumChars = function() {
return numChars;
};
this.getBits = function() {
return bitData.slice();
};
};
/*-- Static factory functions --*/
// Returns a segment representing the given binary data encoded in byte mode.
this.QrSegment.makeBytes = function(data) {
var bb = new BitBuffer();
data.forEach(function(b) {
bb.appendBits(b, 8);
});
return new this(this.Mode.BYTE, data.length, bb.getBits());
};
// Returns a segment representing the given string of decimal digits encoded in numeric mode.
this.QrSegment.makeNumeric = function(digits) {
if (!QrSegment.NUMERIC_REGEX.test(digits))
throw "String contains non-numeric characters";
var bb = new BitBuffer();
var i;
for (i = 0; i + 3 <= digits.length; i += 3) // Process groups of 3
bb.appendBits(parseInt(digits.substr(i, 3), 10), 10);
var rem = digits.length - i;
if (rem > 0) // 1 or 2 digits remaining
bb.appendBits(parseInt(digits.substring(i), 10), rem * 3 + 1);
return new this(this.Mode.NUMERIC, digits.length, bb.getBits());
};
// Returns a segment representing the given text string encoded in alphanumeric mode. The characters allowed are:
// 0 to 9, A to Z (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
this.QrSegment.makeAlphanumeric = function(text) {
if (!QrSegment.ALPHANUMERIC_REGEX.test(text))
throw "String contains unencodable characters in alphanumeric mode";
var bb = new BitBuffer();
var i;
for (i = 0; i + 2 <= text.length; i += 2) { // Process groups of 2
var temp = QrSegment.ALPHANUMERIC_ENCODING_TABLE[text.charCodeAt(i) - 32] * 45;
temp += QrSegment.ALPHANUMERIC_ENCODING_TABLE[text.charCodeAt(i + 1) - 32];
bb.appendBits(temp, 11);
}
if (i < text.length) // 1 character remaining
bb.appendBits(QrSegment.ALPHANUMERIC_ENCODING_TABLE[text.charCodeAt(i) - 32], 6);
return new this(this.Mode.ALPHANUMERIC, text.length, bb.getBits());
};
/*-- Constants --*/
var QrSegment = {}; // Private object to assign properties to
// Can test whether a string is encodable in numeric mode (such as by using QrSegment.makeNumeric()).
QrSegment.NUMERIC_REGEX = /^[0-9]*$/;
// Can test whether a string is encodable in alphanumeric mode (such as by using QrSegment.makeAlphanumeric()).
QrSegment.ALPHANUMERIC_REGEX = /^[A-Z0-9 $%*+.\/:-]*$/;
QrSegment.ALPHANUMERIC_ENCODING_TABLE = [
// SP, !, ", #, $, %, &, ', (, ), *, +, ,, -, ., /, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, :, ;, <, =, >, ?, @, // ASCII codes 32 to 64
36, -1, -1, -1, 37, 38, -1, -1, -1, -1, 39, 40, -1, 41, 42, 43, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 44, -1, -1, -1, -1, -1, -1, // Array indices 0 to 32
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, // Array indices 33 to 58
// A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, // ASCII codes 65 to 90
];
/*
* A public helper enumeration that represents the mode field of a segment.
* Objects are immutable. Provides methods to retrieve closely related values.
*/
this.QrSegment.Mode = { // Constants
NUMERIC : new Mode(0x1, [10, 12, 14]),
ALPHANUMERIC: new Mode(0x2, [ 9, 11, 13]),
BYTE : new Mode(0x4, [ 8, 16, 16]),
KANJI : new Mode(0x8, [ 8, 10, 12]),
};
// Private constructor for the enum.
function Mode(mode, ccbits) {
// Returns an unsigned 4-bit integer value (range 0 to 15) representing the mode indicator bits for this mode object.
this.getModeBits = function() {
return mode;
};
// Returns the bit width of the segment character count field for this mode object at the given version number.
this.numCharCountBits = function(ver) {
if ( 1 <= ver && ver <= 9) return ccbits[0];
else if (10 <= ver && ver <= 26) return ccbits[1];
else if (27 <= ver && ver <= 40) return ccbits[2];
else throw "Version number out of range";
};
}
/*---- Private helper functions and classes ----*/
// Returns a new array of bytes representing the given string encoded in UTF-8.
function toUtf8ByteArray(str) {
var result = [];
for (var i = 0; i < str.length; i++) {
var c = str.charCodeAt(i);
if (c < 0x80)
result.push(c);
else if (c < 0x800) {
result.push(0xC0 | ((c >>> 6) & 0x1F));
result.push(0x80 | ((c >>> 0) & 0x3F));
} else if (0xD800 <= c && c < 0xDC00) { // High surrogate
i++;
if (i < str.length) {
var d = str.charCodeAt(i);
if (0xDC00 <= d && d < 0xE000) { // Low surrogate
c = ((c & 0x3FF) << 10 | (d & 0x3FF)) + 0x10000;
result.push(0xF0 | ((c >>> 18) & 0x07));
result.push(0x80 | ((c >>> 12) & 0x3F));
result.push(0x80 | ((c >>> 6) & 0x3F));
result.push(0x80 | ((c >>> 0) & 0x3F));
continue;
}
}
throw "Invalid UTF-16 string";
} else if (0xDC00 <= c && c < 0xE000) // Low surrogate
throw "Invalid UTF-16 string";
else if (c < 0x10000) {
result.push(0xE0 | ((c >>> 12) & 0x0F));
result.push(0x80 | ((c >>> 6) & 0x3F));
result.push(0x80 | ((c >>> 0) & 0x3F));
} else
throw "Assertion error";
}
return result;
}
/*
* A private helper class that computes the Reed-Solomon error correction codewords for a sequence of
* data codewords at a given degree. Objects are immutable, and the state only depends on the degree.
* This class exists because the divisor polynomial does not need to be recalculated for every input.
* This constructor creates a Reed-Solomon ECC generator for the given degree. This could be implemented
* as a lookup table over all possible parameter values, instead of as an algorithm.
*/
function ReedSolomonGenerator(degree) {
if (degree < 1 || degree > 255)
throw "Degree out of range";
// Coefficients of the divisor polynomial, stored from highest to lowest power, excluding the leading term which
// is always 1. For example the polynomial x^3 + 255x^2 + 8x + 93 is stored as the uint8 array {255, 8, 93}.
var coefficients = [];
// Start with the monomial x^0
for (var i = 0; i < degree - 1; i++)
coefficients.push(0);
coefficients.push(1);
// Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}),
// drop the highest term, and store the rest of the coefficients in order of descending powers.
// Note that r = 0x02, which is a generator element of this field GF(2^8/0x11D).
var root = 1;
for (var i = 0; i < degree; i++) {
// Multiply the current product by (x - r^i)
for (var j = 0; j < coefficients.length; j++) {
coefficients[j] = ReedSolomonGenerator.multiply(coefficients[j], root);
if (j + 1 < coefficients.length)
coefficients[j] ^= coefficients[j + 1];
}
root = (root << 1) ^ ((root >>> 7) * 0x11D); // Multiply by 0x02 mod GF(2^8/0x11D)
}
// Computes and returns the Reed-Solomon error correction codewords for the given sequence of data codewords.
// The returned object is always a new byte array. This method does not alter this object's state (because it is immutable).
this.getRemainder = function(data) {
// Compute the remainder by performing polynomial division
var result = coefficients.map(function() { return 0; });
data.forEach(function(b) {
var factor = b ^ result[0];
result.shift();
result.push(0);
for (var j = 0; j < result.length; j++)
result[j] ^= ReedSolomonGenerator.multiply(coefficients[j], factor);
});
return result;
};
}
// This static function returns the product of the two given field elements modulo GF(2^8/0x11D). The arguments and
// result are unsigned 8-bit integers. This could be implemented as a lookup table of 256*256 entries of uint8.
ReedSolomonGenerator.multiply = function(x, y) {
if ((x & 0xFF) != x || (y & 0xFF) != y)
throw "Byte out of range";
// Russian peasant multiplication
var z = 0;
for (var i = 7; i >= 0; i--) {
z = (z << 1) ^ ((z >>> 7) * 0x11D);
z ^= ((y >>> i) & 1) * x;
}
if ((z & 0xFF) != z)
throw "Assertion error";
return z;
};
/*
* A private helper class that represents an appendable sequence of bits.
* This constructor creates an empty bit buffer (length 0).
*/
function BitBuffer() {
// Array of bits; each item is the integer 0 or 1
var bitData = [];
/*-- Methods --*/
// Returns the number of bits in the buffer, which is a non-negative value.
this.bitLength = function() {
return bitData.length;
};
// Returns a copy of all bits.
this.getBits = function() {
return bitData.slice();
};
// Returns a copy of all bytes, padding up to the nearest byte.
this.getBytes = function() {
var result = [];
var numBytes = Math.ceil(bitData.length / 8);
for (var i = 0; i < numBytes; i++)
result.push(0);
bitData.forEach(function(bit, i) {
result[i >>> 3] |= bit << (7 - (i & 7));
});
return result;
};
// Appends the given number of bits of the given value to this sequence.
// If 0 <= len <= 31, then this requires 0 <= val < 2^len.
this.appendBits = function(val, len) {
if (len < 0 || len > 32 || len < 32 && (val & ((1 << len) - 1)) != val)
throw "Value out of range";
for (var i = len - 1; i >= 0; i--) // Append bit by bit
bitData.push((val >>> i) & 1);
};
// Appends the bit data of the given segment to this bit buffer.
this.appendData = function(seg) {
seg.getBits().forEach(function(b) { // Append bit by bit
bitData.push(b);
});
};
}
};