目录
- 1.二维码历史
- 2.QT源码
- 3.界面展示
- 4.工程源码链接
1.二维码历史
二维码（2-Dimensional Bar Code），是用某种特定的几何图形按一定规律在平面（二维方向上）分布的黑白相间的图形记录数据符号信息的。它是指在一维条码的基础上扩展出另一维具有可读性的条码，使用黑白矩形图案表示二进制数据，被设备扫描后可获取其中所包含的信息。一维条码的宽度记载着数据，而其长度没有记载数据。二维条码的长度、宽度均记载着数据。二维条码有一维条码没有的“定位点”和“容错机制”。容错机制在即使没有辨识到全部的条码、或是说条码有污损时，也可以正确地还原条码上的信息。
2.QT源码
qrcodegen.hpp
/* * QR Code generator library (C++)* * Copyright (c) Project Nayuki. (MIT License)* https://www.nayuki.io/page/qr-code-generator-library* * 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.*/#pragma once#include <array>
#include <cstdint>
#include <stdexcept>
#include <string>
#include <vector>namespace qrcodegen {/* * A segment of character/binary/control data in a QR Code symbol.* Instances of this class are immutable.* The mid-level way to create a segment is to take the payload data* and call a static factory function such as QrSegment::makeNumeric().* The low-level way to create a segment is to custom-make the bit buffer* and call the QrSegment() constructor with appropriate values.* 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.*/
class QrSegment final {/*---- Public helper enumeration ----*//* * Describes how a segment's data bits are interpreted. Immutable.*/public: class Mode final {/*-- Constants --*/public: static const Mode NUMERIC;public: static const Mode ALPHANUMERIC;public: static const Mode BYTE;public: static const Mode KANJI;public: static const Mode ECI;/*-- Fields --*/// The mode indicator bits, which is a uint4 value (range 0 to 15).private: int modeBits;// Number of character count bits for three different version ranges.private: int numBitsCharCount[3];/*-- Constructor --*/private: Mode(int mode, int cc0, int cc1, int cc2);/*-- Methods --*//* * (Package-private) Returns the mode indicator bits, which is an unsigned 4-bit value (range 0 to 15).*/public: int getModeBits() const;/* * (Package-private) Returns the bit width of the character count field for a segment in* this mode in a QR Code at the given version number. The result is in the range [0, 16].*/public: int numCharCountBits(int ver) const;};/*---- Static factory functions (mid level) ----*//* * Returns a segment representing the given binary data encoded in* byte mode. All input byte vectors are acceptable. Any text string* can be converted to UTF-8 bytes and encoded as a byte mode segment.*/public: static QrSegment makeBytes(const std::vector<std::uint8_t> &data);/* * Returns a segment representing the given string of decimal digits encoded in numeric mode.*/public: static QrSegment makeNumeric(const char *digits);/* * 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.*/public: static QrSegment makeAlphanumeric(const char *text);/* * Returns a list of zero or more segments to represent the given text string. The result* may use various segment modes and switch modes to optimize the length of the bit stream.*/public: static std::vector<QrSegment> makeSegments(const char *text);/* * Returns a segment representing an Extended Channel Interpretation* (ECI) designator with the given assignment value.*/public: static QrSegment makeEci(long assignVal);/*---- Public static helper functions ----*//* * Tests whether the given string can be encoded as a segment in numeric mode.* A string is encodable iff each character is in the range 0 to 9.*/public: static bool isNumeric(const char *text);/* * Tests whether the given string can be encoded as a segment in alphanumeric mode.* A string is encodable iff each character is in the following set: 0 to 9, A to Z* (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.*/public: static bool isAlphanumeric(const char *text);/*---- Instance fields ----*//* The mode indicator of this segment. Accessed through getMode(). */private: const Mode *mode;/* The length of this segment's unencoded data. Measured in characters for* numeric/alphanumeric/kanji mode, bytes for byte mode, and 0 for ECI mode.* Always zero or positive. Not the same as the data's bit length.* Accessed through getNumChars(). */private: int numChars;/* The data bits of this segment. Accessed through getData(). */private: std::vector<bool> data;/*---- Constructors (low level) ----*//* * Creates a new QR Code segment with the given attributes and data.* The character count (numCh) must agree with the mode and the bit buffer length,* but the constraint isn't checked. The given bit buffer is copied and stored.*/public: QrSegment(const Mode &md, int numCh, const std::vector<bool> &dt);/* * Creates a new QR Code segment with the given parameters and data.* The character count (numCh) must agree with the mode and the bit buffer length,* but the constraint isn't checked. The given bit buffer is moved and stored.*/public: QrSegment(const Mode &md, int numCh, std::vector<bool> &&dt);/*---- Methods ----*//* * Returns the mode field of this segment.*/public: const Mode &getMode() const;/* * Returns the character count field of this segment.*/public: int getNumChars() const;/* * Returns the data bits of this segment.*/public: const std::vector<bool> &getData() const;// (Package-private) Calculates the number of bits needed to encode the given segments at// the given version. Returns a non-negative number if successful. Otherwise returns -1 if a// segment has too many characters to fit its length field, or the total bits exceeds INT_MAX.public: static int getTotalBits(const std::vector<QrSegment> &segs, int version);/*---- Private constant ----*//* The set of all legal characters in alphanumeric mode, where* each character value maps to the index in the string. */private: static const char *ALPHANUMERIC_CHARSET;};/* * A QR Code symbol, which is a type of two-dimension barcode.* Invented by Denso Wave and described in the ISO/IEC 18004 standard.* Instances of this class represent an immutable square grid of dark and light cells.* The class provides static factory functions to create a QR Code from text or binary data.* The class covers the QR Code Model 2 specification, supporting all versions (sizes)* from 1 to 40, all 4 error correction levels, and 4 character encoding modes.* * Ways to create a QR Code object:* - High level: Take the payload data and call QrCode::encodeText() or QrCode::encodeBinary().* - Mid level: Custom-make the list of segments and call QrCode::encodeSegments().* - Low level: Custom-make the array of data codeword bytes (including* segment headers and final padding, excluding error correction codewords),* supply the appropriate version number, and call the QrCode() constructor.* (Note that all ways require supplying the desired error correction level.)*/
class QrCode final {/*---- Public helper enumeration ----*//* * The error correction level in a QR Code symbol.*/public: enum class Ecc {LOW = 0 , // The QR Code can tolerate about 7% erroneous codewordsMEDIUM , // The QR Code can tolerate about 15% erroneous codewordsQUARTILE, // The QR Code can tolerate about 25% erroneous codewordsHIGH , // The QR Code can tolerate about 30% erroneous codewords};// Returns a value in the range 0 to 3 (unsigned 2-bit integer).private: static int getFormatBits(Ecc ecl);/*---- Static factory functions (high level) ----*//* * Returns a QR Code 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 2953 or fewer* UTF-8 code units (not Unicode code points) if the low error correction level is used. The smallest possible* QR Code version is automatically chosen for the output. The ECC level of the result may be higher than* the ecl argument if it can be done without increasing the version.*/public: static QrCode encodeText(const char *text, Ecc ecl);/* * Returns a QR Code representing the given binary data 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.* The ECC level of the result may be higher than the ecl argument if it can be done without increasing the version.*/public: static QrCode encodeBinary(const std::vector<std::uint8_t> &data, Ecc ecl);/*---- Static factory functions (mid level) ----*//* * Returns a QR Code representing the given segments with the given encoding parameters.* The smallest possible QR Code version within the given range is automatically* chosen for the output. Iff boostEcl is true, then the ECC level of the result* may be higher than the ecl argument if it can be done without increasing the* version. The mask number is either between 0 to 7 (inclusive) to force that* mask, or -1 to automatically choose an appropriate mask (which may be slow).* This function allows the user to create a custom sequence of segments that switches* between modes (such as alphanumeric and byte) to encode text in less space.* This is a mid-level API; the high-level API is encodeText() and encodeBinary().*/public: static QrCode encodeSegments(const std::vector<QrSegment> &segs, Ecc ecl,int minVersion=1, int maxVersion=40, int mask=-1, bool boostEcl=true); // All optional parameters/*---- Instance fields ----*/// Immutable scalar parameters:/* The version number of this QR Code, which is between 1 and 40 (inclusive).* This determines the size of this barcode. */private: int version;/* The width and height of this QR Code, measured in modules, between* 21 and 177 (inclusive). This is equal to version * 4 + 17. */private: int size;/* The error correction level used in this QR Code. */private: Ecc errorCorrectionLevel;/* The index of the mask pattern used in this QR Code, which is between 0 and 7 (inclusive).* Even if a QR Code is created with automatic masking requested (mask = -1),* the resulting object still has a mask value between 0 and 7. */private: int mask;// Private grids of modules/pixels, with dimensions of size*size:// The modules of this QR Code (false = light, true = dark).// Immutable after constructor finishes. Accessed through getModule().private: std::vector<std::vector<bool> > modules;// Indicates function modules that are not subjected to masking. Discarded when constructor finishes.private: std::vector<std::vector<bool> > isFunction;/*---- Constructor (low level) ----*//* * Creates a new QR Code with the given version number,* error correction level, data codeword bytes, and mask number.* This is a low-level API that most users should not use directly.* A mid-level API is the encodeSegments() function.*/public: QrCode(int ver, Ecc ecl, const std::vector<std::uint8_t> &dataCodewords, int msk);/*---- Public instance methods ----*//* * Returns this QR Code's version, in the range [1, 40].*/public: int getVersion() const;/* * Returns this QR Code's size, in the range [21, 177].*/public: int getSize() const;/* * Returns this QR Code's error correction level.*/public: Ecc getErrorCorrectionLevel() const;/* * Returns this QR Code's mask, in the range [0, 7].*/public: int getMask() const;/* * Returns the color of the module (pixel) at the given coordinates, which is false* for light or true for dark. The top left corner has the coordinates (x=0, y=0).* If the given coordinates are out of bounds, then false (light) is returned.*/public: bool getModule(int x, int y) const;/*---- Private helper methods for constructor: Drawing function modules ----*/// Reads this object's version field, and draws and marks all function modules.private: void drawFunctionPatterns();// Draws two copies of the format bits (with its own error correction code)// based on the given mask and this object's error correction level field.private: void drawFormatBits(int msk);// Draws two copies of the version bits (with its own error correction code),// based on this object's version field, iff 7 <= version <= 40.private: void drawVersion();// Draws a 9*9 finder pattern including the border separator,// with the center module at (x, y). Modules can be out of bounds.private: void drawFinderPattern(int x, int y);// Draws a 5*5 alignment pattern, with the center module// at (x, y). All modules must be in bounds.private: void drawAlignmentPattern(int x, int y);// Sets the color of a module and marks it as a function module.// Only used by the constructor. Coordinates must be in bounds.private: void setFunctionModule(int x, int y, bool isDark);// Returns the color of the module at the given coordinates, which must be in range.private: bool module(int x, int y) const;/*---- 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: std::vector<std::uint8_t> addEccAndInterleave(const std::vector<std::uint8_t> &data) const;// Draws the given sequence of 8-bit codewords (data and error correction) onto the entire// data area of this QR Code. Function modules need to be marked off before this is called.private: void drawCodewords(const std::vector<std::uint8_t> &data);// XORs the codeword modules in this QR Code with the given mask pattern.// The function modules must be marked and the codeword bits must be drawn// before masking. Due to the arithmetic of XOR, calling applyMask() with// the same mask value a second time will undo the mask. A final well-formed// QR Code needs exactly one (not zero, two, etc.) mask applied.private: void applyMask(int msk);// 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: long getPenaltyScore() const;/*---- Private helper functions ----*/// Returns an ascending list of positions of alignment patterns for this version number.// Each position is in the range [0,177), and are used on both the x and y axes.// This could be implemented as lookup table of 40 variable-length lists of unsigned bytes.private: std::vector<int> getAlignmentPatternPositions() const;// Returns the number of data bits that can be stored in a QR Code of the given version number, after// all function modules are excluded. This includes remainder bits, so it might not be a multiple of 8.// The result is in the range [208, 29648]. This could be implemented as a 40-entry lookup table.private: static int getNumRawDataModules(int ver);// 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);// Returns a Reed-Solomon ECC generator polynomial for the given degree. This could be// implemented as a lookup table over all possible parameter values, instead of as an algorithm.private: static std::vector<std::uint8_t> reedSolomonComputeDivisor(int degree);// Returns the Reed-Solomon error correction codeword for the given data and divisor polynomials.private: static std::vector<std::uint8_t> reedSolomonComputeRemainder(const std::vector<std::uint8_t> &data, const std::vector<std::uint8_t> &divisor);// Returns the product of the two given field elements modulo GF(2^8/0x11D).// All inputs are valid. This could be implemented as a 256*256 lookup table.private: static std::uint8_t reedSolomonMultiply(std::uint8_t x, std::uint8_t y);// Can only be called immediately after a light run is added, and// returns either 0, 1, or 2. A helper function for getPenaltyScore().private: int finderPenaltyCountPatterns(const std::array<int,7> &runHistory) const;// Must be called at the end of a line (row or column) of modules. A helper function for getPenaltyScore().private: int finderPenaltyTerminateAndCount(bool currentRunColor, int currentRunLength, std::array<int,7> &runHistory) const;// Pushes the given value to the front and drops the last value. A helper function for getPenaltyScore().private: void finderPenaltyAddHistory(int currentRunLength, std::array<int,7> &runHistory) const;// Returns true iff the i'th bit of x is set to 1.private: static bool getBit(long x, int i);/*---- Constants and tables ----*/// The minimum version number supported in the QR Code Model 2 standard.public: static constexpr int MIN_VERSION = 1;// The maximum version number supported in the QR Code Model 2 standard.public: static constexpr int MAX_VERSION = 40;// For use in getPenaltyScore(), when evaluating which mask is best.private: static const int PENALTY_N1;private: static const int PENALTY_N2;private: static const int PENALTY_N3;private: static const int PENALTY_N4;private: static const std::int8_t ECC_CODEWORDS_PER_BLOCK[4][41];private: static const std::int8_t NUM_ERROR_CORRECTION_BLOCKS[4][41];};/*---- Public exception class ----*//* * Thrown when the supplied data does not fit any QR Code version. Ways to handle this exception include:* - Decrease the error correction level if it was greater than Ecc::LOW.* - If the encodeSegments() function was called with a maxVersion argument, then increase* it if it was less than QrCode::MAX_VERSION. (This advice does not apply to the other* factory functions because they search all versions up to QrCode::MAX_VERSION.)* - Split the text data into better or optimal segments in order to reduce the number of bits required.* - Change the text or binary data to be shorter.* - Change the text to fit the character set of a particular segment mode (e.g. alphanumeric).* - Propagate the error upward to the caller/user.*/
class data_too_long : public std::length_error {public: explicit data_too_long(const std::string &msg);};/* * An appendable sequence of bits (0s and 1s). Mainly used by QrSegment.*/
class BitBuffer final : public std::vector<bool> {/*---- Constructor ----*/// Creates an empty bit buffer (length 0).public: BitBuffer();/*---- Method ----*/// Appends the given number of low-order bits of the given value// to this buffer. Requires 0 <= len <= 31 and val < 2^len.public: void appendBits(std::uint32_t val, int len);};}qrcodegen.cpp
/* * QR Code generator library (C++)* * Copyright (c) Project Nayuki. (MIT License)* https://www.nayuki.io/page/qr-code-generator-library* * 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.*/#include <algorithm>
#include <cassert>
#include <climits>
#include <cstddef>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <utility>
#include "qrcodegen.hpp"using std::int8_t;
using std::uint8_t;
using std::size_t;
using std::vector;namespace qrcodegen {/*---- Class QrSegment ----*/QrSegment::Mode::Mode(int mode, int cc0, int cc1, int cc2) :modeBits(mode) {numBitsCharCount[0] = cc0;numBitsCharCount[1] = cc1;numBitsCharCount[2] = cc2;
}int QrSegment::Mode::getModeBits() const {return modeBits;
}int QrSegment::Mode::numCharCountBits(int ver) const {return numBitsCharCount[(ver + 7) / 17];
}const QrSegment::Mode QrSegment::Mode::NUMERIC (0x1, 10, 12, 14);
const QrSegment::Mode QrSegment::Mode::ALPHANUMERIC(0x2, 9, 11, 13);
const QrSegment::Mode QrSegment::Mode::BYTE (0x4, 8, 16, 16);
const QrSegment::Mode QrSegment::Mode::KANJI (0x8, 8, 10, 12);
const QrSegment::Mode QrSegment::Mode::ECI (0x7, 0, 0, 0);QrSegment QrSegment::makeBytes(const vector<uint8_t> &data) {if (data.size() > static_cast<unsigned int>(INT_MAX))throw std::length_error("Data too long");BitBuffer bb;for (uint8_t b : data)bb.appendBits(b, 8);return QrSegment(Mode::BYTE, static_cast<int>(data.size()), std::move(bb));
}QrSegment QrSegment::makeNumeric(const char *digits) {BitBuffer bb;int accumData = 0;int accumCount = 0;int charCount = 0;for (; *digits != '\0'; digits++, charCount++) {char c = *digits;if (c < '0' || c > '9')throw std::domain_error("String contains non-numeric characters");accumData = accumData * 10 + (c - '0');accumCount++;if (accumCount == 3) {bb.appendBits(static_cast<uint32_t>(accumData), 10);accumData = 0;accumCount = 0;}}if (accumCount > 0) // 1 or 2 digits remainingbb.appendBits(static_cast<uint32_t>(accumData), accumCount * 3 + 1);return QrSegment(Mode::NUMERIC, charCount, std::move(bb));
}QrSegment QrSegment::makeAlphanumeric(const char *text) {BitBuffer bb;int accumData = 0;int accumCount = 0;int charCount = 0;for (; *text != '\0'; text++, charCount++) {const char *temp = std::strchr(ALPHANUMERIC_CHARSET, *text);if (temp == nullptr)throw std::domain_error("String contains unencodable characters in alphanumeric mode");accumData = accumData * 45 + static_cast<int>(temp - ALPHANUMERIC_CHARSET);accumCount++;if (accumCount == 2) {bb.appendBits(static_cast<uint32_t>(accumData), 11);accumData = 0;accumCount = 0;}}if (accumCount > 0) // 1 character remainingbb.appendBits(static_cast<uint32_t>(accumData), 6);return QrSegment(Mode::ALPHANUMERIC, charCount, std::move(bb));
}vector<QrSegment> QrSegment::makeSegments(const char *text) {// Select the most efficient segment encoding automaticallyvector<QrSegment> result;if (*text == '\0'); // Leave result emptyelse if (isNumeric(text))result.push_back(makeNumeric(text));else if (isAlphanumeric(text))result.push_back(makeAlphanumeric(text));else {vector<uint8_t> bytes;for (; *text != '\0'; text++)bytes.push_back(static_cast<uint8_t>(*text));result.push_back(makeBytes(bytes));}return result;
}QrSegment QrSegment::makeEci(long assignVal) {BitBuffer bb;if (assignVal < 0)throw std::domain_error("ECI assignment value out of range");else if (assignVal < (1 << 7))bb.appendBits(static_cast<uint32_t>(assignVal), 8);else if (assignVal < (1 << 14)) {bb.appendBits(2, 2);bb.appendBits(static_cast<uint32_t>(assignVal), 14);} else if (assignVal < 1000000L) {bb.appendBits(6, 3);bb.appendBits(static_cast<uint32_t>(assignVal), 21);} elsethrow std::domain_error("ECI assignment value out of range");return QrSegment(Mode::ECI, 0, std::move(bb));
}QrSegment::QrSegment(const Mode &md, int numCh, const std::vector<bool> &dt) :mode(&md),numChars(numCh),data(dt) {if (numCh < 0)throw std::domain_error("Invalid value");
}QrSegment::QrSegment(const Mode &md, int numCh, std::vector<bool> &&dt) :mode(&md),numChars(numCh),data(std::move(dt)) {if (numCh < 0)throw std::domain_error("Invalid value");
}int QrSegment::getTotalBits(const vector<QrSegment> &segs, int version) {int result = 0;for (const QrSegment &seg : segs) {int ccbits = seg.mode->numCharCountBits(version);if (seg.numChars >= (1L << ccbits))return -1; // The segment's length doesn't fit the field's bit widthif (4 + ccbits > INT_MAX - result)return -1; // The sum will overflow an int typeresult += 4 + ccbits;if (seg.data.size() > static_cast<unsigned int>(INT_MAX - result))return -1; // The sum will overflow an int typeresult += static_cast<int>(seg.data.size());}return result;
}bool QrSegment::isNumeric(const char *text) {for (; *text != '\0'; text++) {char c = *text;if (c < '0' || c > '9')return false;}return true;
}bool QrSegment::isAlphanumeric(const char *text) {for (; *text != '\0'; text++) {if (std::strchr(ALPHANUMERIC_CHARSET, *text) == nullptr)return false;}return true;
}const QrSegment::Mode &QrSegment::getMode() const {return *mode;
}int QrSegment::getNumChars() const {return numChars;
}const std::vector<bool> &QrSegment::getData() const {return data;
}const char *QrSegment::ALPHANUMERIC_CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:";/*---- Class QrCode ----*/int QrCode::getFormatBits(Ecc ecl) {switch (ecl) {case Ecc::LOW : return 1;case Ecc::MEDIUM : return 0;case Ecc::QUARTILE: return 3;case Ecc::HIGH : return 2;default: throw std::logic_error("Unreachable");}
}QrCode QrCode::encodeText(const char *text, Ecc ecl) {vector<QrSegment> segs = QrSegment::makeSegments(text);return encodeSegments(segs, ecl);
}QrCode QrCode::encodeBinary(const vector<uint8_t> &data, Ecc ecl) {vector<QrSegment> segs{QrSegment::makeBytes(data)};return encodeSegments(segs, ecl);
}QrCode QrCode::encodeSegments(const vector<QrSegment> &segs, Ecc ecl,int minVersion, int maxVersion, int mask, bool boostEcl) {if (!(MIN_VERSION <= minVersion && minVersion <= maxVersion && maxVersion <= MAX_VERSION) || mask < -1 || mask > 7)throw std::invalid_argument("Invalid value");// Find the minimal version number to useint version, dataUsedBits;for (version = minVersion; ; version++) {int dataCapacityBits = getNumDataCodewords(version, ecl) * 8; // Number of data bits availabledataUsedBits = QrSegment::getTotalBits(segs, version);if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)break; // This version number is found to be suitableif (version >= maxVersion) { // All versions in the range could not fit the given datastd::ostringstream sb;if (dataUsedBits == -1)sb << "Segment too long";else {sb << "Data length = " << dataUsedBits << " bits, ";sb << "Max capacity = " << dataCapacityBits << " bits";}throw data_too_long(sb.str());}}assert(dataUsedBits != -1);// Increase the error correction level while the data still fits in the current version numberfor (Ecc newEcl : {Ecc::MEDIUM, Ecc::QUARTILE, Ecc::HIGH}) { // From low to highif (boostEcl && dataUsedBits <= getNumDataCodewords(version, newEcl) * 8)ecl = newEcl;}// Concatenate all segments to create the data bit stringBitBuffer bb;for (const QrSegment &seg : segs) {bb.appendBits(static_cast<uint32_t>(seg.getMode().getModeBits()), 4);bb.appendBits(static_cast<uint32_t>(seg.getNumChars()), seg.getMode().numCharCountBits(version));bb.insert(bb.end(), seg.getData().begin(), seg.getData().end());}assert(bb.size() == static_cast<unsigned int>(dataUsedBits));// Add terminator and pad up to a byte if applicablesize_t dataCapacityBits = static_cast<size_t>(getNumDataCodewords(version, ecl)) * 8;assert(bb.size() <= dataCapacityBits);bb.appendBits(0, std::min(4, static_cast<int>(dataCapacityBits - bb.size())));bb.appendBits(0, (8 - static_cast<int>(bb.size() % 8)) % 8);assert(bb.size() % 8 == 0);// Pad with alternating bytes until data capacity is reachedfor (uint8_t padByte = 0xEC; bb.size() < dataCapacityBits; padByte ^= 0xEC ^ 0x11)bb.appendBits(padByte, 8);// Pack bits into bytes in big endianvector<uint8_t> dataCodewords(bb.size() / 8);for (size_t i = 0; i < bb.size(); i++)dataCodewords.at(i >> 3) |= (bb.at(i) ? 1 : 0) << (7 - (i & 7));// Create the QR Code objectreturn QrCode(version, ecl, dataCodewords, mask);
}QrCode::QrCode(int ver, Ecc ecl, const vector<uint8_t> &dataCodewords, int msk) :// Initialize fields and check argumentsversion(ver),errorCorrectionLevel(ecl) {if (ver < MIN_VERSION || ver > MAX_VERSION)throw std::domain_error("Version value out of range");if (msk < -1 || msk > 7)throw std::domain_error("Mask value out of range");size = ver * 4 + 17;size_t sz = static_cast<size_t>(size);modules = vector<vector<bool> >(sz, vector<bool>(sz)); // Initially all lightisFunction = vector<vector<bool> >(sz, vector<bool>(sz));// Compute ECC, draw modulesdrawFunctionPatterns();const vector<uint8_t> allCodewords = addEccAndInterleave(dataCodewords);drawCodewords(allCodewords);// Do maskingif (msk == -1) { // Automatically choose best masklong minPenalty = LONG_MAX;for (int i = 0; i < 8; i++) {applyMask(i);drawFormatBits(i);long penalty = getPenaltyScore();if (penalty < minPenalty) {msk = i;minPenalty = penalty;}applyMask(i); // Undoes the mask due to XOR}}assert(0 <= msk && msk <= 7);mask = msk;applyMask(msk); // Apply the final choice of maskdrawFormatBits(msk); // Overwrite old format bitsisFunction.clear();isFunction.shrink_to_fit();
}int QrCode::getVersion() const {return version;
}int QrCode::getSize() const {return size;
}QrCode::Ecc QrCode::getErrorCorrectionLevel() const {return errorCorrectionLevel;
}int QrCode::getMask() const {return mask;
}bool QrCode::getModule(int x, int y) const {return 0 <= x && x < size && 0 <= y && y < size && module(x, y);
}void QrCode::drawFunctionPatterns() {// Draw horizontal and vertical timing patternsfor (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 numerous alignment patternsconst vector<int> alignPatPos = getAlignmentPatternPositions();size_t numAlign = alignPatPos.size();for (size_t i = 0; i < numAlign; i++) {for (size_t j = 0; j < numAlign; j++) {// Don't draw on the three finder cornersif (!((i == 0 && j == 0) || (i == 0 && j == numAlign - 1) || (i == numAlign - 1 && j == 0)))drawAlignmentPattern(alignPatPos.at(i), alignPatPos.at(j));}}// Draw configuration datadrawFormatBits(0); // Dummy mask value; overwritten later in the constructordrawVersion();
}void QrCode::drawFormatBits(int msk) {// Calculate error correction code and pack bitsint data = getFormatBits(errorCorrectionLevel) << 3 | msk; // errCorrLvl is uint2, msk is uint3int rem = data;for (int i = 0; i < 10; i++)rem = (rem << 1) ^ ((rem >> 9) * 0x537);int bits = (data << 10 | rem) ^ 0x5412; // uint15assert(bits >> 15 == 0);// Draw first copyfor (int i = 0; i <= 5; i++)setFunctionModule(8, i, getBit(bits, i));setFunctionModule(8, 7, getBit(bits, 6));setFunctionModule(8, 8, getBit(bits, 7));setFunctionModule(7, 8, getBit(bits, 8));for (int i = 9; i < 15; i++)setFunctionModule(14 - i, 8, getBit(bits, i));// Draw second copyfor (int i = 0; i < 8; i++)setFunctionModule(size - 1 - i, 8, getBit(bits, i));for (int i = 8; i < 15; i++)setFunctionModule(8, size - 15 + i, getBit(bits, i));setFunctionModule(8, size - 8, true); // Always dark
}void QrCode::drawVersion() {if (version < 7)return;// Calculate error correction code and pack bitsint rem = version; // version is uint6, in the range [7, 40]for (int i = 0; i < 12; i++)rem = (rem << 1) ^ ((rem >> 11) * 0x1F25);long bits = static_cast<long>(version) << 12 | rem; // uint18assert(bits >> 18 == 0);// Draw two copiesfor (int i = 0; i < 18; i++) {bool bit = getBit(bits, i);int a = size - 11 + i % 3;int b = i / 3;setFunctionModule(a, b, bit);setFunctionModule(b, a, bit);}
}void QrCode::drawFinderPattern(int x, int y) {for (int dy = -4; dy <= 4; dy++) {for (int dx = -4; dx <= 4; dx++) {int dist = std::max(std::abs(dx), std::abs(dy)); // Chebyshev/infinity normint xx = x + dx, yy = y + dy;if (0 <= xx && xx < size && 0 <= yy && yy < size)setFunctionModule(xx, yy, dist != 2 && dist != 4);}}
}void QrCode::drawAlignmentPattern(int x, int y) {for (int dy = -2; dy <= 2; dy++) {for (int dx = -2; dx <= 2; dx++)setFunctionModule(x + dx, y + dy, std::max(std::abs(dx), std::abs(dy)) != 1);}
}void QrCode::setFunctionModule(int x, int y, bool isDark) {size_t ux = static_cast<size_t>(x);size_t uy = static_cast<size_t>(y);modules .at(uy).at(ux) = isDark;isFunction.at(uy).at(ux) = true;
}bool QrCode::module(int x, int y) const {return modules.at(static_cast<size_t>(y)).at(static_cast<size_t>(x));
}vector<uint8_t> QrCode::addEccAndInterleave(const vector<uint8_t> &data) const {if (data.size() != static_cast<unsigned int>(getNumDataCodewords(version, errorCorrectionLevel)))throw std::invalid_argument("Invalid argument");// Calculate parameter numbersint numBlocks = NUM_ERROR_CORRECTION_BLOCKS[static_cast<int>(errorCorrectionLevel)][version];int blockEccLen = ECC_CODEWORDS_PER_BLOCK [static_cast<int>(errorCorrectionLevel)][version];int rawCodewords = getNumRawDataModules(version) / 8;int numShortBlocks = numBlocks - rawCodewords % numBlocks;int shortBlockLen = rawCodewords / numBlocks;// Split data into blocks and append ECC to each blockvector<vector<uint8_t> > blocks;const vector<uint8_t> rsDiv = reedSolomonComputeDivisor(blockEccLen);for (int i = 0, k = 0; i < numBlocks; i++) {vector<uint8_t> dat(data.cbegin() + k, data.cbegin() + (k + shortBlockLen - blockEccLen + (i < numShortBlocks ? 0 : 1)));k += static_cast<int>(dat.size());const vector<uint8_t> ecc = reedSolomonComputeRemainder(dat, rsDiv);if (i < numShortBlocks)dat.push_back(0);dat.insert(dat.end(), ecc.cbegin(), ecc.cend());blocks.push_back(std::move(dat));}// Interleave (not concatenate) the bytes from every block into a single sequencevector<uint8_t> result;for (size_t i = 0; i < blocks.at(0).size(); i++) {for (size_t j = 0; j < blocks.size(); j++) {// Skip the padding byte in short blocksif (i != static_cast<unsigned int>(shortBlockLen - blockEccLen) || j >= static_cast<unsigned int>(numShortBlocks))result.push_back(blocks.at(j).at(i));}}assert(result.size() == static_cast<unsigned int>(rawCodewords));return result;
}void QrCode::drawCodewords(const vector<uint8_t> &data) {if (data.size() != static_cast<unsigned int>(getNumRawDataModules(version) / 8))throw std::invalid_argument("Invalid argument");size_t i = 0; // Bit index into the data// Do the funny zigzag scanfor (int right = size - 1; right >= 1; right -= 2) { // Index of right column in each column pairif (right == 6)right = 5;for (int vert = 0; vert < size; vert++) { // Vertical counterfor (int j = 0; j < 2; j++) {size_t x = static_cast<size_t>(right - j); // Actual x coordinatebool upward = ((right + 1) & 2) == 0;size_t y = static_cast<size_t>(upward ? size - 1 - vert : vert); // Actual y coordinateif (!isFunction.at(y).at(x) && i < data.size() * 8) {modules.at(y).at(x) = getBit(data.at(i >> 3), 7 - static_cast<int>(i & 7));i++;}// If this QR Code has any remainder bits (0 to 7), they were assigned as// 0/false/light by the constructor and are left unchanged by this method}}}assert(i == data.size() * 8);
}void QrCode::applyMask(int msk) {if (msk < 0 || msk > 7)throw std::domain_error("Mask value out of range");size_t sz = static_cast<size_t>(size);for (size_t y = 0; y < sz; y++) {for (size_t x = 0; x < sz; x++) {bool invert;switch (msk) {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 std::logic_error("Unreachable");}modules.at(y).at(x) = modules.at(y).at(x) ^ (invert & !isFunction.at(y).at(x));}}
}long QrCode::getPenaltyScore() const {long result = 0;// Adjacent modules in row having same color, and finder-like patternsfor (int y = 0; y < size; y++) {bool runColor = false;int runX = 0;std::array<int,7> runHistory = {};for (int x = 0; x < size; x++) {if (module(x, y) == runColor) {runX++;if (runX == 5)result += PENALTY_N1;else if (runX > 5)result++;} else {finderPenaltyAddHistory(runX, runHistory);if (!runColor)result += finderPenaltyCountPatterns(runHistory) * PENALTY_N3;runColor = module(x, y);runX = 1;}}result += finderPenaltyTerminateAndCount(runColor, runX, runHistory) * PENALTY_N3;}// Adjacent modules in column having same color, and finder-like patternsfor (int x = 0; x < size; x++) {bool runColor = false;int runY = 0;std::array<int,7> runHistory = {};for (int y = 0; y < size; y++) {if (module(x, y) == runColor) {runY++;if (runY == 5)result += PENALTY_N1;else if (runY > 5)result++;} else {finderPenaltyAddHistory(runY, runHistory);if (!runColor)result += finderPenaltyCountPatterns(runHistory) * PENALTY_N3;runColor = module(x, y);runY = 1;}}result += finderPenaltyTerminateAndCount(runColor, runY, runHistory) * PENALTY_N3;}// 2*2 blocks of modules having same colorfor (int y = 0; y < size - 1; y++) {for (int x = 0; x < size - 1; x++) {bool color = module(x, y);if ( color == module(x + 1, y) &&color == module(x, y + 1) &&color == module(x + 1, y + 1))result += PENALTY_N2;}}// Balance of dark and light modulesint dark = 0;for (const vector<bool> &row : modules) {for (bool color : row) {if (color)dark++;}}int total = size * size; // Note that size is odd, so dark/total != 1/2// Compute the smallest integer k >= 0 such that (45-5k)% <= dark/total <= (55+5k)%int k = static_cast<int>((std::abs(dark * 20L - total * 10L) + total - 1) / total) - 1;assert(0 <= k && k <= 9);result += k * PENALTY_N4;assert(0 <= result && result <= 2568888L); // Non-tight upper bound based on default values of PENALTY_N1, ..., N4return result;
}vector<int> QrCode::getAlignmentPatternPositions() const {if (version == 1)return vector<int>();else {int numAlign = version / 7 + 2;int step = (version == 32) ? 26 :(version * 4 + numAlign * 2 + 1) / (numAlign * 2 - 2) * 2;vector<int> result;for (int i = 0, pos = size - 7; i < numAlign - 1; i++, pos -= step)result.insert(result.begin(), pos);result.insert(result.begin(), 6);return result;}
}int QrCode::getNumRawDataModules(int ver) {if (ver < MIN_VERSION || ver > MAX_VERSION)throw std::domain_error("Version number out of range");int result = (16 * ver + 128) * ver + 64;if (ver >= 2) {int numAlign = ver / 7 + 2;result -= (25 * numAlign - 10) * numAlign - 55;if (ver >= 7)result -= 36;}assert(208 <= result && result <= 29648);return result;
}int QrCode::getNumDataCodewords(int ver, Ecc ecl) {return getNumRawDataModules(ver) / 8- ECC_CODEWORDS_PER_BLOCK [static_cast<int>(ecl)][ver]* NUM_ERROR_CORRECTION_BLOCKS[static_cast<int>(ecl)][ver];
}vector<uint8_t> QrCode::reedSolomonComputeDivisor(int degree) {if (degree < 1 || degree > 255)throw std::domain_error("Degree out of range");// Polynomial coefficients are 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}.vector<uint8_t> result(static_cast<size_t>(degree));result.at(result.size() - 1) = 1; // Start off with the monomial x^0// Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}),// and drop the highest monomial term which is always 1x^degree.// Note that r = 0x02, which is a generator element of this field GF(2^8/0x11D).uint8_t root = 1;for (int i = 0; i < degree; i++) {// Multiply the current product by (x - r^i)for (size_t j = 0; j < result.size(); j++) {result.at(j) = reedSolomonMultiply(result.at(j), root);if (j + 1 < result.size())result.at(j) ^= result.at(j + 1);}root = reedSolomonMultiply(root, 0x02);}return result;
}vector<uint8_t> QrCode::reedSolomonComputeRemainder(const vector<uint8_t> &data, const vector<uint8_t> &divisor) {vector<uint8_t> result(divisor.size());for (uint8_t b : data) { // Polynomial divisionuint8_t factor = b ^ result.at(0);result.erase(result.begin());result.push_back(0);for (size_t i = 0; i < result.size(); i++)result.at(i) ^= reedSolomonMultiply(divisor.at(i), factor);}return result;
}uint8_t QrCode::reedSolomonMultiply(uint8_t x, uint8_t y) {// Russian peasant multiplicationint z = 0;for (int i = 7; i >= 0; i--) {z = (z << 1) ^ ((z >> 7) * 0x11D);z ^= ((y >> i) & 1) * x;}assert(z >> 8 == 0);return static_cast<uint8_t>(z);
}int QrCode::finderPenaltyCountPatterns(const std::array<int,7> &runHistory) const {int n = runHistory.at(1);assert(n <= size * 3);bool core = n > 0 && runHistory.at(2) == n && runHistory.at(3) == n * 3 && runHistory.at(4) == n && runHistory.at(5) == n;return (core && runHistory.at(0) >= n * 4 && runHistory.at(6) >= n ? 1 : 0)+ (core && runHistory.at(6) >= n * 4 && runHistory.at(0) >= n ? 1 : 0);
}int QrCode::finderPenaltyTerminateAndCount(bool currentRunColor, int currentRunLength, std::array<int,7> &runHistory) const {if (currentRunColor) { // Terminate dark runfinderPenaltyAddHistory(currentRunLength, runHistory);currentRunLength = 0;}currentRunLength += size; // Add light border to final runfinderPenaltyAddHistory(currentRunLength, runHistory);return finderPenaltyCountPatterns(runHistory);
}void QrCode::finderPenaltyAddHistory(int currentRunLength, std::array<int,7> &runHistory) const {if (runHistory.at(0) == 0)currentRunLength += size; // Add light border to initial runstd::copy_backward(runHistory.cbegin(), runHistory.cend() - 1, runHistory.end());runHistory.at(0) = currentRunLength;
}bool QrCode::getBit(long x, int i) {return ((x >> i) & 1) != 0;
}/*---- Tables of constants ----*/const int QrCode::PENALTY_N1 = 3;
const int QrCode::PENALTY_N2 = 3;
const int QrCode::PENALTY_N3 = 40;
const int QrCode::PENALTY_N4 = 10;const int8_t QrCode::ECC_CODEWORDS_PER_BLOCK[4][41] = {// 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, 18, 20, 24, 30, 18, 20, 24, 26, 30, 22, 24, 28, 30, 28, 28, 28, 28, 30, 30, 26, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30}, // Low{-1, 10, 16, 26, 18, 24, 16, 18, 22, 22, 26, 30, 22, 22, 24, 24, 28, 28, 26, 26, 26, 26, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28}, // Medium{-1, 13, 22, 18, 26, 18, 24, 18, 22, 20, 24, 28, 26, 24, 20, 30, 24, 28, 28, 26, 30, 28, 30, 30, 30, 30, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30}, // Quartile{-1, 17, 28, 22, 16, 22, 28, 26, 26, 24, 28, 24, 28, 22, 24, 24, 30, 28, 28, 26, 28, 30, 24, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30}, // High
};const int8_t QrCode::NUM_ERROR_CORRECTION_BLOCKS[4][41] = {// 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
};data_too_long::data_too_long(const std::string &msg) :std::length_error(msg) {}/*---- Class BitBuffer ----*/BitBuffer::BitBuffer(): std::vector<bool>() {}void BitBuffer::appendBits(std::uint32_t val, int len) {if (len < 0 || len > 31 || val >> len != 0)throw std::domain_error("Value out of range");for (int i = len - 1; i >= 0; i--) // Append bit by bitthis->push_back(((val >> i) & 1) != 0);
}}mainwindow.cpp
// 使用utf8编码QByteArray str = ui->lineEdit->text().toUtf8();const char *text = str.constData();// 二维码有四个纠错等级，从低到高：L-%7/M-%15/Q-%25/H-%30const qrcodegen::QrCode::Ecc level = qrcodegen::QrCode::Ecc::MEDIUM;// 生成二维码try{// 使用简易接口，默认 Version 范围 min=1, max=40// const qrcodegen::QrCode qr = qrcodegen::QrCode::encodeText(text, level);// 也可以指定符号版本，越大可容纳的信息越多，如果内容超出容量范围会抛异常// 根据规范，Version1 是 21x21，Version2 是 25x25，每增加一个Version，就比前一版本每边增加 4 个模块std::vector<qrcodegen::QrSegment> segs = qrcodegen::QrSegment::makeSegments(text);const qrcodegen::QrCode qr = qrcodegen::QrCode::encodeSegments(segs, level, 1, 40);const int size = qr.getSize();// 填充位图QImage image = QImage(size, size, QImage::Format_Grayscale8);for (int row = 0; row < size; ++row){uchar *line_ptr = image.scanLine(row);for (int col = 0; col < size; ++col){line_ptr[col] = (uchar)(qr.getModule(row, col) ? 0x00 : 0xFF);}}// 放大一点看得更清楚image = image.scaled(image.width() * 5, image.height() * 5);// 生成后可以用手机扫一扫识别文字内容，注意内容为空可能扫不出来ui->label->setPixmap(QPixmap::fromImage(image));}catch(std::invalid_argument e){// 参数异常，如 minVersion > maxVersionqDebug() << "catch invalid_argument" << e.what();}catch(qrcodegen::data_too_long e){// 内容太长qDebug() << "catch data_too_long" << e.what();}
3.界面展示
4.工程源码链接
CSDN：https://download.csdn.net/download/weixin_43996145/90042738