fix qr-code generation for large configurations (#374)

internal/app/configfile/manager.go

@@ -15,6 +15,7 @@ import (
 	"github.com/sirupsen/logrus"
 	evbus "github.com/vardius/message-bus"
 	"github.com/yeqown/go-qrcode/v2"
+	"github.com/yeqown/go-qrcode/writer/compressed"
 )
 
 type Manager struct {
@@ -27,7 +28,13 @@ type Manager struct {
 	wg     WireguardDatabaseRepo
 }
 
-func NewConfigFileManager(cfg *config.Config, bus evbus.MessageBus, users UserDatabaseRepo, wg WireguardDatabaseRepo, fsRepo FileSystemRepo) (*Manager, error) {
+func NewConfigFileManager(
+	cfg *config.Config,
+	bus evbus.MessageBus,
+	users UserDatabaseRepo,
+	wg WireguardDatabaseRepo,
+	fsRepo FileSystemRepo,
+) (*Manager, error) {
 	tplHandler, err := newTemplateHandler()
 	if err != nil {
 		return nil, fmt.Errorf("failed to initialize template handler: %w", err)
@@ -156,18 +163,19 @@ func (m Manager) GetPeerConfigQrCode(ctx context.Context, id domain.PeerIdentifi
 		return nil, fmt.Errorf("failed to read peer config for %s: %w", id, err)
 	}
 
-	code, err := qrcode.New(sb.String())
+	code, err := qrcode.NewWith(sb.String(),
+		qrcode.WithErrorCorrectionLevel(qrcode.ErrorCorrectionLow), qrcode.WithEncodingMode(qrcode.EncModeByte))
 	if err != nil {
-		return nil, fmt.Errorf("failed to initializeqr code for %s: %w", id, err)
+		return nil, fmt.Errorf("failed to initialize qr code for %s: %w", id, err)
 	}
 
 	buf := bytes.NewBuffer(nil)
 	wr := nopCloser{Writer: buf}
-	option := Option{
+	option := compressed.Option{
 		Padding:   8, // padding pixels around the qr code.
 		BlockSize: 4, // block pixels which represents a bit data.
 	}
-	qrWriter := NewCompressedWriter(wr, &option)
+	qrWriter := compressed.NewWithWriter(wr, &option)
 	err = code.Save(qrWriter)
 	if err != nil {
 		return nil, fmt.Errorf("failed to write code for %s: %w", id, err)

internal/app/configfile/qrwriter.go

@@ -1,88 +0,0 @@
-package configfile
-
-// waiting for https://github.com/yeqown/go-qrcode/pull/85 to get merged
-// meanwhile we use our own writer implementation
-
-import (
-	"image"
-	"image/color"
-	"image/png"
-	"io"
-
-	"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 NewCompressedWriter(writer io.WriteCloser, opt *Option) qrcode.Writer {
-	return compressedWriter{fd: writer, option: opt}
-}
-
-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()
-}