feat(issue#69): implement a compressed writer, ref issue#69 (yeqown#72)

implement a compressed writer, ref issue#69

.issues/go.mod

@@ -0,0 +1,9 @@
+module issues
+
+go 1.19
+
+require (
+	github.com/yeqown/go-qrcode/v2 v2.2.0
+	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e
+)
+

.issues/issue69/issue69.go

@@ -0,0 +1,141 @@
+/*
+ * Link:	https://github.com/yeqown/go-qrcode/issues/69
+ * Title:	Feature(image-compression): PNG bit depth must be 1
+ * Author:  stokito(https://github.com/stokito)
+ */
+
+package main
+
+import (
+	"fmt"
+	"image"
+	"image/png"
+	"io"
+	"os"
+	"strings"
+
+	skip2 "github.com/skip2/go-qrcode"
+
+	yeqown "github.com/yeqown/go-qrcode/v2"
+	yeqownwstd "github.com/yeqown/go-qrcode/writer/compressed"
+)
+
+/*
+See https://github.com/yeqown/go-qrcode/issues/69
+Results: (unit: B)
+Content length:     158   // source text length
+qr-skip2-best.png:  641   // skip2 generated size
+qr-yeqown-best.png: 958  // yeqown best compression level
+*/
+func main() {
+	// some json
+	content := "{\n  \"id\": \"beb6c04733d1a2da0f87c910a384\",\n  \"tmax\": 895,\n  \"cur\": [\n    \"USD\"\n  ],\n  \"imp\": [\n    {\n      \"id\": \"21292\",\n      \"instl\": 0,\n      \"secure\": 0}\n"
+	// strip json to alpha num just for a test
+	content = strings.Replace(content, "{", "$", -1)
+	content = strings.Replace(content, "}", "%", -1)
+	content = strings.Replace(content, "\n", " ", -1)
+	content = strings.Replace(content, "\"", "*", -1)
+	content = strings.Replace(content, ",", "/", -1)
+	content = strings.Replace(content, "[", "/", -1)
+	content = strings.Replace(content, "]", "/", -1)
+	content = strings.ToUpper(content)
+	fmt.Printf("Content lenght: %d\n", len(content))
+	//imgEncoderNone := CustomPngEncoder{png.NoCompression}
+	imgEncoderBest := CustomPngEncoder{png.BestCompression}
+
+	encodeWithYeqown(content, "qr-yeqown.png")
+	//encodeWithYeqownCompression(content, "qr-yeqown-none.png", imgEncoderNone)
+	encodeWithYeqownCompression(content, "qr-yeqown-best.png", imgEncoderBest)
+	encodeWithSkip2(content, "qr-skip2-best.png")
+}
+
+func encodeWithSkip2(content, name string) {
+	//err := skip2.WriteFile(content, skip2.Highest, 0, name)
+	//if err != nil {
+	//	log.Fatal(err)
+	//}
+	q, err := skip2.New(content, skip2.Highest)
+	if err != nil {
+		panic(err)
+	}
+	err = q.WriteFile(0, name)
+	if err != nil {
+		panic(err)
+	}
+	stat, _ := os.Stat(name)
+	fmt.Printf("%s: %v\n", name, stat.Size())
+}
+
+type CustomPngEncoder struct {
+	CompressionLevel png.CompressionLevel
+}
+
+func (j CustomPngEncoder) Encode(w io.Writer, img image.Image) error {
+	pngEncoder := png.Encoder{CompressionLevel: j.CompressionLevel}
+	return pngEncoder.Encode(w, img)
+}
+
+func encodeWithYeqown(content, name string) {
+	qrc, err := yeqown.NewWith(content,
+		yeqown.WithEncodingMode(yeqown.EncModeAlphanumeric),
+		yeqown.WithErrorCorrectionLevel(yeqown.ErrorCorrectionHighest),
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	option := yeqownwstd.Option{
+		Padding:   4,
+		BlockSize: 1,
+	}
+	stdw, err := yeqownwstd.New(name, &option)
+	if err != nil {
+		panic(err)
+	}
+
+	if err := qrc.Save(stdw); err != nil {
+		panic(err)
+	}
+
+	stat, _ := os.Stat(name)
+	fmt.Printf("%s: %v\n", name, stat.Size())
+}
+
+func encodeWithYeqownCompression(content, name string, imageEncoder CustomPngEncoder) {
+	//cfg := yeqown.DefaultConfig()
+	//cfg.EncMode = yeqown.EncModeAlphanumeric
+	////cfg.EncMode = yeqown.EncModeByte
+	//cfg.EcLevel = yeqown.ErrorCorrectionHighest
+	//
+	//imgOpts := yeqown.WithCustomImageEncoder(imageEncoder)
+	//imgOpts2 := yeqown.WithQRWidth(1)
+	//imgOpts3 := yeqown.WithBorderWidth(4)
+	//qrc, err := yeqown.NewWithConfig(content, cfg, imgOpts, imgOpts2, imgOpts3)
+	//if err != nil {
+	//	panic(err)
+	//}
+
+	qrc, err := yeqown.NewWith(content,
+		yeqown.WithEncodingMode(yeqown.EncModeAlphanumeric),
+		yeqown.WithErrorCorrectionLevel(yeqown.ErrorCorrectionHighest),
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	option := yeqownwstd.Option{
+		Padding:   4,
+		BlockSize: 1,
+	}
+	stdw, err := yeqownwstd.New(name, &option)
+	if err != nil {
+		panic(err)
+	}
+
+	if err := qrc.Save(stdw); err != nil {
+		panic(err)
+	}
+
+	stat, _ := os.Stat(name)
+	fmt.Printf("%s: %v\n", name, stat.Size())
+}

go.work

@@ -0,0 +1,9 @@
+go 1.19
+
+use (
+	.
+	./.issues
+	./writer/compressed
+	./writer/standard
+	./writer/terminal
+)

writer/compressed/go.mod

@@ -0,0 +1,7 @@
+module github.com/yeqown/go-qrcode/writer/compressed
+
+go 1.19
+
+require (
+	github.com/yeqown/go-qrcode/v2 v2.2.0
+)

writer/compressed/writer.go

@@ -0,0 +1,91 @@
+package compressed
+
+import (
+	"image"
+	"image/color"
+	"image/png"
+	"io"
+	"os"
+
+	"github.com/yeqown/go-qrcode/v2"
+)
+
+type Option struct {
+	Padding   int
+	BlockSize int
+}
+
+// compressedWriter implements issue#69, generating compressed images
+// in some special situations, such as, network transferring.
+// https://github.com/yeqown/go-qrcode/issues/69
+type compressedWriter struct {
+	fd io.WriteCloser
+
+	option *Option
+}
+
+var (
+	backgroundColor = color.Gray{Y: 0xff}
+	foregroundColor = color.Gray{Y: 0x00}
+)
+
+func New(filename string, opt *Option) (qrcode.Writer, error) {
+	fd, err := os.OpenFile(filename, os.O_RDWR|os.O_CREATE, 0644)
+	if err != nil {
+		return nil, err
+	}
+
+	return compressedWriter{fd: fd, option: opt}, nil
+}
+
+func (w compressedWriter) Write(mat qrcode.Matrix) error {
+	padding := w.option.Padding
+	blockWidth := w.option.BlockSize
+	width := mat.Width()*blockWidth + 2*padding
+	height := width
+
+	img := image.NewPaletted(
+		image.Rect(0, 0, width, height),
+		color.Palette([]color.Color{backgroundColor, foregroundColor}),
+	)
+	bgColor := uint8(img.Palette.Index(backgroundColor))
+	fgColor := uint8(img.Palette.Index(foregroundColor))
+
+	rectangle := func(x1, y1 int, x2, y2 int, img *image.Paletted, color uint8) {
+		for x := x1; x < x2; x++ {
+			for y := y1; y < y2; y++ {
+				pos := img.PixOffset(x, y)
+				img.Pix[pos] = color
+			}
+		}
+	}
+
+	// background
+	rectangle(0, 0, width, height, img, bgColor)
+
+	mat.Iterate(qrcode.IterDirection_COLUMN, func(x int, y int, v qrcode.QRValue) {
+		sx := x*blockWidth + padding
+		sy := y*blockWidth + padding
+		es := (x+1)*blockWidth + padding
+		ey := (y+1)*blockWidth + padding
+
+		if v.IsSet() {
+			rectangle(sx, sy, es, ey, img, fgColor)
+		}
+
+		//switch v.IsSet() {
+		//case false:
+		//	gray = backgroundColor
+		//default:
+		//	gray = foregroundColor
+		//}
+
+	})
+
+	encoder := png.Encoder{CompressionLevel: png.BestCompression}
+	return encoder.Encode(w.fd, img)
+}
+
+func (w compressedWriter) Close() error {
+	return w.fd.Close()
+}