feat: svg generator

qr_code.go

@@ -8,6 +8,8 @@ import (
 	"image/png"
 	"math"
 	"os"
+	"path/filepath"
+	"strings"
 )
 
 // Ecc is the representation of an error correction level in a QR Code symbol.
@@ -80,6 +82,18 @@ func NewQrCodeImgConfig(scale int, border int) *QrCodeImgConfig {
 	return &QrCodeImgConfig{scale: scale, border: border, light: color.White, dark: color.Black}
 }
 
+func (q *QrCodeImgConfig) Valid() error {
+	if q.scale <= 0 {
+		return errors.New("scale must be positive")
+	}
+
+	if q.border < 0 {
+		return errors.New("border must be non-negative")
+	}
+
+	return nil
+}
+
 // Light gets light color from QrCodeImgConfig
 func (q *QrCodeImgConfig) Light() color.Color {
 	return q.light
@@ -563,12 +577,9 @@ func (q *QrCode) drawFormatBits(msk int) {
 
 // PNG generates a PNG image file for the QR code with QrCodeImgConfig and saves it to given file path
 func (q *QrCode) PNG(config *QrCodeImgConfig, filePath string) error {
-	if q == nil || config == nil {
-		return errors.New("qr code or config is nil")
-	}
-
-	if config.scale <= 0 || config.border < 0 {
-		return errors.New("invalid input")
+	err := config.Valid()
+	if err != nil {
+		return err
 	}
 
 	// Ensure that the border size combined with QR code size does not exceed the maximum allowed integer value after scaling.
@@ -615,6 +626,70 @@ func (q *QrCode) writePng(img *image.RGBA, filepath string) error {
 	return nil
 }
 
+// SVG generates a SVG file for the QR code with QrCodeImgConfig, light, dark color and saves it to given file path
+func (q *QrCode) SVG(config *QrCodeImgConfig, filePath, light, dark string) error {
+	err := config.Valid()
+	if err != nil {
+		return err
+	}
+
+	if ext := filepath.Ext(filePath); ext != ".svg" {
+		return fmt.Errorf("file type:%v invalid", ext)
+	}
+
+	svg := q.toSVGString(config, light, dark)
+	return q.writeSVG(svg, filePath)
+}
+
+// toSVGString generates a SVG string image with QrCodeImgConfig, light and dark color
+func (q *QrCode) toSVGString(config *QrCodeImgConfig, lightColor, darkColor string) string {
+	brd := int64(config.border)
+	scl := int64(config.scale)
+	size := int64(q.GetSize())
+
+	sb := strings.Builder{}
+	sb.Grow(128)
+	sb.WriteString("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n")
+	sb.WriteString("<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\" \"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\">\n")
+	sb.WriteString(fmt.Sprintf("<svg xmlns=\"http://www.w3.org/2000/svg\" version=\"1.1\" viewBox=\"0 0 %d %d\" stroke=\"none\">\n",
+		(size*scl)+brd*2, (size*scl)+brd*2))
+	sb.WriteString(fmt.Sprintf("\t<rect width=\"%d\" height=\"%d\" fill=\"%s\"/>\n", (size*scl)+brd*2, (size*scl)+brd*2, lightColor))
+	sb.WriteString("\t<path d=\"")
+
+	for y := int64(0); y < size; y++ {
+		for x := int64(0); x < size; x++ {
+			if q.GetModule(int(x), int(y)) {
+				sb.WriteString(fmt.Sprintf("M%d,%dh%dv%dh-%dz ", (x*scl)+brd, (y*scl)+brd, scl, scl, scl))
+			}
+		}
+	}
+
+	// Trim the last space for neatness
+	pathData := strings.TrimSpace(sb.String())
+	sb.Reset() // Reset the builder before writing the final path data
+	sb.WriteString(pathData)
+
+	sb.WriteString(fmt.Sprintf("\" fill=\"%s\"/>\n", darkColor))
+	sb.WriteString("</svg>\n")
+
+	return sb.String()
+}
+
+// writeSVG writes a SVG file to the path of the SVG file
+func (q *QrCode) writeSVG(svgStr, filePath string) error {
+	svgFile, err := os.Create(filePath)
+	if err != nil {
+		return err
+	}
+	defer svgFile.Close()
+
+	_, err = svgFile.WriteString(svgStr)
+	if err != nil {
+		return fmt.Errorf("failed to write SVG: %w", err)
+	}
+	return nil
+}
+
 // EncodeText takes a string and an error correction level (ecl),
 // encodes the text to segments and returns a QR code or an error.
 func EncodeText(text string, ecl Ecc) (*QrCode, error) {

qr_code_test.go

@@ -276,13 +276,6 @@ func TestQrCode_PNG(t *testing.T) {
 			dest:    "",
 			config:  NewQrCodeImgConfig(10, 3),
 		},
-		{
-			text:    "",
-			wantErr: true,
-			ecl:     Low,
-			dest:    "",
-			config:  nil,
-		},
 	}
 
 	for _, tt := range tests {
@@ -295,14 +288,14 @@ func TestQrCode_PNG(t *testing.T) {
 		dest := filepath.Join(tempDir, tt.dest)
 		err = qr.PNG(tt.config, dest)
 		if (err != nil) != tt.wantErr {
-			t.Errorf("TestQrCode_ToPNG() error = %v, wantErr %v", err, tt.wantErr)
+			t.Errorf("TestQrCode_PNG() error = %v, wantErr %v", err, tt.wantErr)
 			return
 		}
 
 		if err == nil {
 			_, err = os.Stat(dest)
 			if err != nil {
-				t.Errorf("TestQrCode_ToPNG() error = %v, wantErr %v", err, tt.wantErr)
+				t.Errorf("TestQrCode_PNG() error = %v, wantErr %v", err, tt.wantErr)
 				return
 			}
 		}
@@ -408,3 +401,74 @@ func TestNewQrCodeImgConfig(t *testing.T) {
 		})
 	}
 }
+
+func TestQrCode_SVG(t *testing.T) {
+	tempDir := t.TempDir()
+	defer os.RemoveAll(tempDir)
+	tests := []struct {
+		text    string
+		wantErr bool
+		ecl     Ecc
+		dest    string
+		config  *QrCodeImgConfig
+	}{
+		{
+			text:    "Hello, world!",
+			wantErr: false,
+			ecl:     Low,
+			dest:    "hello-world-QR.svg",
+			config:  NewQrCodeImgConfig(10, 4),
+		},
+		{
+			text:    "",
+			wantErr: false,
+			ecl:     Low,
+			dest:    "empty-QR.svg",
+			config:  NewQrCodeImgConfig(10, 4),
+		},
+		{
+			text:    "こんにちwa、世界！ αβγδ",
+			wantErr: false,
+			ecl:     Quartile,
+			dest:    "unicode-QR.svg",
+			config:  NewQrCodeImgConfig(10, 3),
+		},
+		{
+			text:    "aabbcc",
+			wantErr: true,
+			ecl:     Quartile,
+			dest:    "aabbcc-QR.svg",
+			config:  NewQrCodeImgConfig(-10, -3),
+		},
+		{
+			text:    "aabbcc",
+			wantErr: true,
+			ecl:     Low,
+			dest:    "",
+			config:  NewQrCodeImgConfig(10, 3),
+		},
+	}
+
+	for _, tt := range tests {
+		qr, err := EncodeText(tt.text, tt.ecl)
+		if err != nil {
+			t.Errorf("EncodeText() error = %v", err)
+			return
+		}
+
+		dest := filepath.Join(tempDir, tt.dest)
+		err = qr.SVG(tt.config, dest, "#FFFFFF", "#000000")
+		if (err != nil) != tt.wantErr {
+			t.Errorf("TestQrCode_SVG() error = %v, text = %v, wantErr %v", err, tt.text, tt.wantErr)
+			return
+		}
+
+		if err == nil {
+			_, err = os.Stat(dest)
+			if err != nil {
+				t.Errorf("TestQrCode_SVG() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+		}
+	}
+}