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qrcode.go
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qrcode.go
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package qrcode
import (
"fmt"
"log"
"math"
"sync"
"github.com/yeqown/reedsolomon"
"github.com/yeqown/reedsolomon/binary"
)
// New generate a QRCode struct to create
func New(text string) (*QRCode, error) {
dst := DefaultEncodingOption()
return build(text, dst)
}
// NewWith generate a QRCode struct with
// specified `ver`(QR version) and `ecLv`(Error Correction level)
func NewWith(text string, opts ...EncodeOption) (*QRCode, error) {
dst := DefaultEncodingOption()
for _, opt := range opts {
opt.apply(dst)
}
return build(text, dst)
}
func build(text string, option *encodingOption) (*QRCode, error) {
qrc := &QRCode{
sourceText: text,
sourceRawBytes: []byte(text),
dataBSet: nil,
mat: nil,
ecBSet: nil,
v: version{},
encodingOption: option,
encoder: nil,
}
// initialize QRCode instance
if err := qrc.init(); err != nil {
return nil, err
}
qrc.masking()
return qrc, nil
}
// QRCode contains fields to generate QRCode matrix, outputImageOptions to Draw image,
// etc.
type QRCode struct {
sourceText string // sourceText input text
sourceRawBytes []byte // raw Data to transfer
dataBSet *binary.Binary // final data bit stream of encode data
mat *Matrix // matrix grid to store final bitmap
ecBSet *binary.Binary // final error correction bitset
encodingOption *encodingOption
encoder *encoder // encoder ptr to call its methods ~
v version // indicate the QR version to encode.
}
func (q *QRCode) Save(w Writer) error {
if w == nil {
w = nonWriter{}
}
defer func() {
if err := w.Close(); err != nil {
log.Printf("[WARNNING] [go-qrcode] close writer failed: %v\n", err)
}
}()
return w.Write(*q.mat)
}
func (q *QRCode) Dimension() int {
if q.mat == nil {
return 0
}
return q.mat.Width()
}
// init fill QRCode instance from settings and sourceText.
func (q *QRCode) init() (err error) {
// choose encode mode (num, alpha num, byte, Japanese)
if q.encodingOption.EncMode == EncModeAuto {
q.encodingOption.EncMode = analyzeEncodeModeFromRaw(q.sourceRawBytes)
}
// choose version
if _, err = q.calcVersion(); err != nil {
return fmt.Errorf("init: calc version failed: %v", err)
}
q.mat = newMatrix(q.v.Dimension(), q.v.Dimension())
_ = q.applyEncoder()
var (
dataBlocks []dataBlock // data encoding blocks
ecBlocks []ecBlock // error correction blocks
)
// data encoding, and be split into blocks
if dataBlocks, err = q.dataEncoding(); err != nil {
return err
}
// generate er bitsets, and also be split into blocks
if ecBlocks, err = q.errorCorrectionEncoding(dataBlocks); err != nil {
return err
}
// arrange data blocks and EC blocks
q.arrangeBits(dataBlocks, ecBlocks)
// append ec bits after data bits
q.dataBSet.Append(q.ecBSet)
// append remainder bits
q.dataBSet.AppendNumBools(q.v.RemainderBits, false)
// initial the 2d matrix
q.prefillMatrix()
return nil
}
// calcVersion
func (q *QRCode) calcVersion() (ver *version, err error) {
var needAnalyze = true
opt := q.encodingOption
if opt.Version >= 1 && opt.Version <= 40 &&
opt.EcLevel >= ErrorCorrectionLow && opt.EcLevel <= ErrorCorrectionHighest {
// only version and EC level are specified, can skip analyzeVersionAuto
needAnalyze = false
}
// automatically parse version
if needAnalyze {
// analyzeVersion the input data to choose to adapt version
analyzed, err2 := analyzeVersion(q.sourceRawBytes, opt.EcLevel, opt.EncMode)
if err2 != nil {
err = fmt.Errorf("calcVersion: analyzeVersionAuto failed: %v", err2)
return nil, err
}
opt.Version = analyzed.Ver
}
q.v = loadVersion(opt.Version, opt.EcLevel)
return
}
// applyEncoder
func (q *QRCode) applyEncoder() error {
q.encoder = newEncoder(q.encodingOption.EncMode, q.encodingOption.EcLevel, q.v)
return nil
}
// dataEncoding ref to:
// https://www.thonky.com/qr-code-tutorial/data-encoding
func (q *QRCode) dataEncoding() (blocks []dataBlock, err error) {
var (
bset *binary.Binary
)
bset, err = q.encoder.Encode(q.sourceRawBytes)
if err != nil {
err = fmt.Errorf("could not encode data: %v", err)
return
}
blocks = make([]dataBlock, q.v.TotalNumBlocks())
// split bitset into data Block
start, end, blockID := 0, 0, 0
for _, g := range q.v.Groups {
for j := 0; j < g.NumBlocks; j++ {
start = end
end = start + g.NumDataCodewords*8
blocks[blockID].Data, err = bset.Subset(start, end)
if err != nil {
panic(err)
}
blocks[blockID].StartOffset = end - start
blocks[blockID].NumECBlock = g.ECBlockwordsPerBlock
blockID++
}
}
return
}
// dataBlock ...
type dataBlock struct {
Data *binary.Binary
StartOffset int // length
NumECBlock int // error correction codewords num per data block
}
// ecBlock ...
type ecBlock struct {
Data *binary.Binary
// StartOffset int // length
}
// errorCorrectionEncoding ref to:
// https://www.thonky.com/qr-code-tutorial /error-correction-coding
func (q *QRCode) errorCorrectionEncoding(dataBlocks []dataBlock) (blocks []ecBlock, err error) {
// start, end, blockID := 0, 0, 0
blocks = make([]ecBlock, q.v.TotalNumBlocks())
for idx, b := range dataBlocks {
debugLogf("numOfECBlock: %d", b.NumECBlock)
bset := reedsolomon.Encode(b.Data, b.NumECBlock)
blocks[idx].Data, err = bset.Subset(b.StartOffset, bset.Len())
if err != nil {
panic(err)
}
// blocks[idx].StartOffset = b.StartOffset
}
return
}
// arrangeBits ... and save into dataBSet
func (q *QRCode) arrangeBits(dataBlocks []dataBlock, ecBlocks []ecBlock) {
if debugEnabled() {
log.Println("arrangeBits called, before")
for i := 0; i < len(ecBlocks); i++ {
debugLogf("ec block_%d: %v", i, ecBlocks[i])
}
for i := 0; i < len(dataBlocks); i++ {
debugLogf("data block_%d: %v", i, dataBlocks[i])
}
}
// arrange data blocks
var (
overflowCnt = 0
endFlag = false
curIdx = 0
start, end int
)
// check if bitsets initialized, or initial them
if q.dataBSet == nil {
q.dataBSet = binary.New()
}
if q.ecBSet == nil {
q.ecBSet = binary.New()
}
for !endFlag {
for _, block := range dataBlocks {
start = curIdx * 8
end = start + 8
if start >= block.Data.Len() {
overflowCnt++
continue
}
subBin, err := block.Data.Subset(start, end)
if err != nil {
panic(err)
}
q.dataBSet.Append(subBin)
debugLogf("arrange data blocks info: start: %d, end: %d, len: %d, overflowCnt: %d, curIdx: %d",
start, end, block.Data.Len(), overflowCnt, curIdx,
)
}
curIdx++
// loop finish check
if overflowCnt >= len(dataBlocks) {
endFlag = true
}
}
// arrange ec blocks and reinitialize
endFlag = false
overflowCnt = 0
curIdx = 0
for !endFlag {
for _, block := range ecBlocks {
start = curIdx * 8
end = start + 8
if start >= block.Data.Len() {
overflowCnt++
continue
}
subBin, err := block.Data.Subset(start, end)
if err != nil {
panic(err)
}
q.ecBSet.Append(subBin)
}
curIdx++
// loop finish check
if overflowCnt >= len(ecBlocks) {
endFlag = true
}
}
debugLogf("arrangeBits called, after")
debugLogf("data bitsets: %s", q.dataBSet.String())
debugLogf("ec bitsets: %s", q.ecBSet.String())
}
// prefillMatrix with version info: ref to:
// http://www.thonky.com/qr-code-tutorial/module-placement-matrix
func (q *QRCode) prefillMatrix() {
dimension := q.v.Dimension()
if q.mat == nil {
q.mat = newMatrix(dimension, dimension)
}
// add finder left-top
addFinder(q.mat, 0, 0)
addSplitter(q.mat, 7, 7, dimension)
debugLogf("finish left-top finder")
// add finder right-top
addFinder(q.mat, dimension-7, 0)
addSplitter(q.mat, dimension-8, 7, dimension)
debugLogf("finish right-top finder")
// add finder left-bottom
addFinder(q.mat, 0, dimension-7)
addSplitter(q.mat, 7, dimension-8, dimension)
debugLogf("finish left-bottom finder")
// only version-1 QR code has no alignment module
if q.v.Ver > 1 {
// add align-mode related to version cfg
for _, loc := range loadAlignmentPatternLoc(q.v.Ver) {
addAlignment(q.mat, loc.X, loc.Y)
}
debugLogf("finish align")
}
// add timing line
addTimingLine(q.mat, dimension)
// add darkBlock always be position (4*ver+9, 8)
addDarkBlock(q.mat, 8, 4*q.v.Ver+9)
// reserveFormatBlock for version and format info
reserveFormatBlock(q.mat, dimension)
// reserveVersionBlock for version over 7
// only version 7 and larger version should add version info
if q.v.Ver >= 7 {
reserveVersionBlock(q.mat, dimension)
}
}
// add finder module
func addFinder(m *Matrix, top, left int) {
// black outer
x, y := top, left
for i := 0; i < 24; i++ {
_ = m.set(x, y, QRValue_FINDER_V1)
if i < 6 {
x = x + 1
} else if i < 12 {
y = y + 1
} else if i < 18 {
x = x - 1
} else {
y = y - 1
}
}
// white inner
x, y = top+1, left+1
for i := 0; i < 16; i++ {
_ = m.set(x, y, QRValue_FINDER_V0)
if i < 4 {
x = x + 1
} else if i < 8 {
y = y + 1
} else if i < 12 {
x = x - 1
} else {
y = y - 1
}
}
// black inner
for x = left + 2; x < left+5; x++ {
for y = top + 2; y < top+5; y++ {
_ = m.set(x, y, QRValue_FINDER_V1)
}
}
}
// add splitter module
func addSplitter(m *Matrix, x, y, dimension int) {
// top-left
if x == 7 && y == 7 {
for pos := 0; pos < 8; pos++ {
_ = m.set(x, pos, QRValue_SPLITTER_V0)
_ = m.set(pos, y, QRValue_SPLITTER_V0)
}
return
}
// top-right
if x == dimension-8 && y == 7 {
for pos := 0; pos < 8; pos++ {
_ = m.set(x, y-pos, QRValue_SPLITTER_V0)
_ = m.set(x+pos, y, QRValue_SPLITTER_V0)
}
return
}
// bottom-left
if x == 7 && y == dimension-8 {
for pos := 0; pos < 8; pos++ {
_ = m.set(x, y+pos, QRValue_SPLITTER_V0)
_ = m.set(x-pos, y, QRValue_SPLITTER_V0)
}
return
}
}
// add matrix align module
func addAlignment(m *Matrix, centerX, centerY int) {
_ = m.set(centerX, centerY, QRValue_DATA_V1)
// black
x, y := centerX-2, centerY-2
for i := 0; i < 16; i++ {
_ = m.set(x, y, QRValue_DATA_V1)
if i < 4 {
x = x + 1
} else if i < 8 {
y = y + 1
} else if i < 12 {
x = x - 1
} else {
y = y - 1
}
}
// white
x, y = centerX-1, centerY-1
for i := 0; i < 8; i++ {
_ = m.set(x, y, QRValue_DATA_V0)
if i < 2 {
x = x + 1
} else if i < 4 {
y = y + 1
} else if i < 6 {
x = x - 1
} else {
y = y - 1
}
}
}
// addTimingLine ...
func addTimingLine(m *Matrix, dimension int) {
for pos := 8; pos < dimension-8; pos++ {
if pos%2 == 0 {
_ = m.set(6, pos, QRValue_TIMING_V1)
_ = m.set(pos, 6, QRValue_TIMING_V1)
} else {
_ = m.set(6, pos, QRValue_TIMING_V0)
_ = m.set(pos, 6, QRValue_TIMING_V0)
}
}
}
// addDarkBlock ...
func addDarkBlock(m *Matrix, x, y int) {
_ = m.set(x, y, QRValue_DARK_V1)
}
// reserveFormatBlock maintain the position in matrix for format info
func reserveFormatBlock(m *Matrix, dimension int) {
for pos := 1; pos < 9; pos++ {
// skip timing line
if pos == 6 {
_ = m.set(8, dimension-pos, QRValue_FORMAT_V0)
_ = m.set(dimension-pos, 8, QRValue_FORMAT_V0)
continue
}
// skip dark module
if pos == 8 {
_ = m.set(8, pos, QRValue_FORMAT_V0) // top-left-column
_ = m.set(pos, 8, QRValue_FORMAT_V0) // top-left-row
_ = m.set(dimension-pos, 8, QRValue_FORMAT_V0) // top-right-row
continue
}
_ = m.set(8, pos, QRValue_FORMAT_V0) // top-left-column
_ = m.set(pos, 8, QRValue_FORMAT_V0) // top-left-row
_ = m.set(dimension-pos, 8, QRValue_FORMAT_V0) // top-right-row
_ = m.set(8, dimension-pos, QRValue_FORMAT_V0) // bottom-left-column
}
// fix(@yeqown): b4b5ae3 reduced two format reversed blocks on top-left-column and top-left-row.
_ = m.set(0, 8, QRValue_FORMAT_V0)
_ = m.set(8, 0, QRValue_FORMAT_V0)
}
// reserveVersionBlock maintain the position in matrix for version info
func reserveVersionBlock(m *Matrix, dimension int) {
// 3x6=18 cells
for i := 1; i <= 3; i++ {
for pos := 0; pos < 6; pos++ {
_ = m.set(dimension-8-i, pos, QRValue_VERSION_V0)
_ = m.set(pos, dimension-8-i, QRValue_VERSION_V0)
}
}
}
// fillDataBinary fill q.dataBSet binary stream into q.mat.
// References:
// * http://www.thonky.com/qr-code-tutorial/module-placement-matrix#Place-the-Data-Bits
//
func (q *QRCode) fillDataBinary(m *Matrix, dimension int) {
var (
// x always move from right, left right loop (2 rows), y move upward, downward, upward loop
x, y = dimension - 1, dimension - 1
l = q.dataBSet.Len()
upForward = true
pos int
)
for i := 0; pos < l; i++ {
// debugLogf("fillDataBinary: dimension: %d, len: %d: pos: %d", dimension, l, pos)
set := QRValue_DATA_V0
if q.dataBSet.At(pos) {
set = QRValue_DATA_V1
}
state, err := m.at(x, y)
if err != nil {
if err == ErrorOutRangeOfW {
break
}
if err == ErrorOutRangeOfH {
// turn around while y is out of range.
x = x - 2
switch upForward {
case true:
y = y + 1
default:
y = y - 1
}
if x == 7 || x == 6 {
x = x - 1
}
upForward = !upForward
state, err = m.at(x, y) // renew state qrbool after turn around writing direction.
}
}
// data bit should only be set into un-set block in matrix.
if state.qrtype() == QRType_INIT {
_ = m.set(x, y, set)
pos++
debugLogf("normal set turn forward: upForward: %v, x: %d, y: %d", upForward, x, y)
}
// DO NOT CHANGE FOLLOWING CODE FOR NOW !!!
// change x, y
mod2 := i % 2
// in one 8bit block
if upForward {
if mod2 == 0 {
x = x - 1
} else {
y = y - 1
x = x + 1
}
} else {
if mod2 == 0 {
x = x - 1
} else {
y = y + 1
x = x + 1
}
}
}
debugLogf("fillDone and x: %d, y: %d, pos: %d, total: %d", x, y, pos, l)
}
// draw from bitset to matrix.Matrix, calculate all mask modula score,
// then decide which mask to use according to the mask's score (the lowest one).
func (q *QRCode) masking() {
type maskScore struct {
Score int
Idx int
}
var (
masks = make([]*mask, 8)
mats = make([]*Matrix, 8)
lowScore = math.MaxInt32
markMatsIdx int
scoreChan = make(chan maskScore, 8)
wg sync.WaitGroup
)
dimension := q.v.Dimension()
// fill bitset into matrix
cpy := q.mat.Copy()
q.fillDataBinary(cpy, dimension)
// init mask and mats
for i := 0; i < 8; i++ {
masks[i] = newMask(q.mat, maskPatternModulo(i))
mats[i] = cpy.Copy()
}
// generate 8 matrix with mask
for i := 0; i < 8; i++ {
wg.Add(1)
go func(i int) {
_ = debugDraw(fmt.Sprintf("draft/mats_%d.jpeg", i), *mats[i])
_ = debugDraw(fmt.Sprintf("draft/mask_%d.jpeg", i), *masks[i].mat)
// xor with mask
q.xorMask(mats[i], masks[i])
_ = debugDraw(fmt.Sprintf("draft/mats_mask_%d.jpeg", i), *mats[i])
// fill format info
q.fillFormatInfo(mats[i], maskPatternModulo(i), dimension)
// version7 and larger version has version info
if q.v.Ver >= 7 {
q.fillVersionInfo(mats[i], dimension)
}
// calculate score and decide the lowest score and Draw
score := evaluation(mats[i])
debugLogf("cur idx: %d, score: %d, current lowest: mats[%d]:%d", i, score, markMatsIdx, lowScore)
scoreChan <- maskScore{
Score: score,
Idx: i,
}
_ = debugDraw(fmt.Sprintf("draft/qrcode_mask_%d.jpeg", i), *mats[i])
wg.Done()
}(i)
}
wg.Wait()
close(scoreChan)
for c := range scoreChan {
if c.Score < lowScore {
lowScore = c.Score
markMatsIdx = c.Idx
}
}
q.mat = mats[markMatsIdx]
}
// all mask patter and check the maskScore choose the lowest mask result
func (q *QRCode) xorMask(m *Matrix, mask *mask) {
mask.mat.iter(IterDirection_COLUMN, func(x, y int, v qrvalue) {
// skip the empty place
if v.qrtype() == QRType_INIT {
return
}
v2, _ := m.at(x, y)
_ = m.set(x, y, v2.xor(v))
})
}
// fillVersionInfo ref to:
// https://www.thonky.com/qr-code-tutorial/format-version-tables
func (q *QRCode) fillVersionInfo(m *Matrix, dimension int) {
bin := q.v.verInfo()
// from high bit to lowest
pos := 0
for j := 5; j >= 0; j-- {
for i := 1; i <= 3; i++ {
if bin.At(pos) {
_ = m.set(dimension-8-i, j, QRValue_VERSION_V1)
_ = m.set(j, dimension-8-i, QRValue_VERSION_V1)
} else {
_ = m.set(dimension-8-i, j, QRValue_VERSION_V0)
_ = m.set(j, dimension-8-i, QRValue_VERSION_V0)
}
pos++
}
}
}
// fill format info ref to:
// https://www.thonky.com/qr-code-tutorial/format-version-tables
func (q *QRCode) fillFormatInfo(m *Matrix, mode maskPatternModulo, dimension int) {
fmtBSet := q.v.formatInfo(int(mode))
debugLogf("fmtBitSet: %s", fmtBSet.String())
var (
x, y = 0, dimension - 1
)
for pos := 0; pos < 15; pos++ {
if fmtBSet.At(pos) {
// row
_ = m.set(x, 8, QRValue_FORMAT_V1)
// column
_ = m.set(8, y, QRValue_FORMAT_V1)
} else {
// row
_ = m.set(x, 8, QRValue_FORMAT_V0)
// column
_ = m.set(8, y, QRValue_FORMAT_V0)
}
x = x + 1
y = y - 1
// row skip
if x == 6 {
x = 7
} else if x == 8 {
x = dimension - 8
}
// column skip
if y == dimension-8 {
y = 8
} else if y == 6 {
y = 5
}
}
}