目录
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
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.
*/
#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 codewords
MEDIUM , // The QR Code can tolerate about 15% erroneous codewords
QUARTILE, // The QR Code can tolerate about 25% erroneous codewords
HIGH , // 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
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 remaining
bb.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 remaining
bb.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 automatically
vector<QrSegment> result;
if (*text == '\0'); // Leave result empty
else 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);
} else
throw 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 width
if (4 + ccbits > INT_MAX - result)
return -1; // The sum will overflow an int type
result += 4 + ccbits;
if (seg.data.size() > static_cast<unsigned int>(INT_MAX - result))
return -1; // The sum will overflow an int type
result += 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 use
int version, dataUsedBits;
for (version = minVersion; ; version++) {
int dataCapacityBits = getNumDataCodewords(version, ecl) * 8; // Number of data bits available
dataUsedBits = QrSegment::getTotalBits(segs, version);
if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)
break; // This version number is found to be suitable
if (version >= maxVersion) { // All versions in the range could not fit the given data
std::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 number
for (Ecc newEcl : {Ecc::MEDIUM, Ecc::QUARTILE, Ecc::HIGH}) { // From low to high
if (boostEcl && dataUsedBits <= getNumDataCodewords(version, newEcl) * 8)
ecl = newEcl;
}
// Concatenate all segments to create the data bit string
BitBuffer 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 applicable
size_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 reached
for (uint8_t padByte = 0xEC; bb.size() < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
bb.appendBits(padByte, 8);
// Pack bits into bytes in big endian
vector<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 object
return QrCode(version, ecl, dataCodewords, mask);
}
QrCode::QrCode(int ver, Ecc ecl, const vector<uint8_t> &dataCodewords, int msk) :
// Initialize fields and check arguments
version(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 light
isFunction = vector<vector<bool> >(sz, vector<bool>(sz));
// Compute ECC, draw modules
drawFunctionPatterns();
const vector<uint8_t> allCodewords = addEccAndInterleave(dataCodewords);
drawCodewords(allCodewords);
// Do masking
if (msk == -1) { // Automatically choose best mask
long 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 mask
drawFormatBits(msk); // Overwrite old format bits
isFunction.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 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 numerous alignment patterns
const 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 corners
if (!((i == 0 && j == 0) || (i == 0 && j == numAlign - 1) || (i == numAlign - 1 && j == 0)))
drawAlignmentPattern(alignPatPos.at(i), alignPatPos.at(j));
}
}
// Draw configuration data
drawFormatBits(0); // Dummy mask value; overwritten later in the constructor
drawVersion();
}
void QrCode::drawFormatBits(int msk) {
// Calculate error correction code and pack bits
int data = getFormatBits(errorCorrectionLevel) << 3 | msk; // errCorrLvl is uint2, msk is uint3
int rem = data;
for (int i = 0; i < 10; i++)
rem = (rem << 1) ^ ((rem >> 9) * 0x537);
int bits = (data << 10 | rem) ^ 0x5412; // uint15
assert(bits >> 15 == 0);
// Draw first copy
for (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 copy
for (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 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);
long bits = static_cast<long>(version) << 12 | rem; // uint18
assert(bits >> 18 == 0);
// Draw two copies
for (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 norm
int 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 numbers
int 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 block
vector<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 sequence
vector<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 blocks
if (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 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++) {
size_t x = static_cast<size_t>(right - j); // Actual x coordinate
bool upward = ((right + 1) & 2) == 0;
size_t y = static_cast<size_t>(upward ? size - 1 - vert : vert); // Actual y coordinate
if (!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 patterns
for (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 patterns
for (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 color
for (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 modules
int 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, ..., N4
return 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 division
uint8_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 multiplication
int 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 run
finderPenaltyAddHistory(currentRunLength, runHistory);
currentRunLength = 0;
}
currentRunLength += size; // Add light border to final run
finderPenaltyAddHistory(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 run
std::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 bit
this->push_back(((val >> i) & 1) != 0);
}
}mainwindow.cpp
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-%30
const 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 > maxVersion
qDebug() << "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