generate multi letter image

draw.go

@@ -20,6 +20,9 @@ type Options struct {
 	Palette     []color.Color
 	LetterColor color.Color
 
+	// FontSize is used to set font size
+	FontSize int
+
 	// PaletteKey is used to pick the background color from the Palette.
 	// Using the same PaletteKey leads to the same background color being picked.
 	// If PaletteKey is empty (default) the background color is picked randomly.
@@ -30,7 +33,7 @@ var defaultLetterColor = color.RGBA{0xf0, 0xf0, 0xf0, 0xf0}
 
 // Draw generates a new letter-avatar image of the given size using the given letter
 // with the given options. Default parameters are used if a nil *Options is passed.
-func Draw(size int, letter rune, options *Options) (image.Image, error) {
+func Draw(size int, letter []rune, options *Options) (image.Image, error) {
 	font := defaultFont
 	if options != nil && options.Font != nil {
 		font = options.Font
@@ -55,14 +58,18 @@ func Draw(size int, letter rune, options *Options) (image.Image, error) {
 		}
 	}
 
-	return drawAvatar(bgColor, letterColor, font, size, letter)
+	fontSize := float64(options.FontSize)
+	if options.FontSize == 0 {
+		fontSize = float64(size) * 0.6
+	}
+
+	return drawAvatar(bgColor, letterColor, font, size, fontSize, letter)
 }
 
-func drawAvatar(bgColor, fgColor color.Color, font *truetype.Font, size int, letter rune) (image.Image, error) {
+func drawAvatar(bgColor, fgColor color.Color, font *truetype.Font, size int, fontSize float64, letter []rune) (image.Image, error) {
 	dst := newRGBA(size, size, bgColor)
 
-	fontSize := float64(size) * 0.6
-	src, err := drawString(bgColor, fgColor, font, fontSize, string(letter))
+	src, err := drawString(bgColor, fgColor, font, fontSize, letter)
 	if err != nil {
 		return nil, err
 	}
@@ -73,12 +80,15 @@ func drawAvatar(bgColor, fgColor color.Color, font *truetype.Font, size int, let
 	return dst, nil
 }
 
-func drawString(bgColor, fgColor color.Color, font *truetype.Font, fontSize float64, str string) (image.Image, error) {
+func drawString(bgColor, fgColor color.Color, font *truetype.Font, fontSize float64, letter []rune) (image.Image, error) {
 	c := freetype.NewContext()
 	c.SetDPI(72)
 
 	bb := font.Bounds(c.PointToFixed(fontSize))
 	w := bb.Max.X.Ceil() - bb.Min.X.Floor()
+	if len(letter) > 0 {
+		w = w + int(fontSize)*(len(letter)-1)
+	}
 	h := bb.Max.Y.Ceil() - bb.Min.Y.Floor()
 
 	dst := newRGBA(w, h, bgColor)
@@ -90,7 +100,7 @@ func drawString(bgColor, fgColor color.Color, font *truetype.Font, fontSize floa
 	c.SetFontSize(fontSize)
 	c.SetFont(font)
 
-	p, err := c.DrawString(str, fixed.Point26_6{X: 0, Y: bb.Max.Y})
+	p, err := c.DrawString(string(letter), fixed.Point26_6{X: 0, Y: bb.Max.Y})
 	if err != nil {
 		return nil, err
 	}

example/example.go → example/firstletter/example.go

@@ -28,7 +28,7 @@ func main() {
 	for _, name := range names {
 		firstLetter, _ := utf8.DecodeRuneInString(name)
 
-		img, err := letteravatar.Draw(75, firstLetter, nil)
+		img, err := letteravatar.Draw(75, []rune{firstLetter}, &letteravatar.Options{})
 		if err != nil {
 			log.Fatal(err)
 		}

example/multiletter/example.go

@@ -0,0 +1,69 @@
+package main
+
+import (
+	"image/png"
+	"io/ioutil"
+	"log"
+	"os"
+
+	"github.com/golang/freetype/truetype"
+
+	"github.com/disintegration/letteravatar"
+)
+
+var names = []string{
+	"Alice",
+	"Bob",
+	"Carol",
+	"Dave",
+	"Eve",
+	"Frank",
+	"Gloria",
+	"Henry",
+	"Isabella",
+	"James",
+	"Жозефина",
+	"Ярослав",
+	"中国文化",
+}
+
+func main() {
+	font, err := loadFont("./PingFang-SC-Regular.ttf")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	opt := &letteravatar.Options{
+		FontSize: 20,
+		Font:     font,
+	}
+	for _, name := range names {
+
+		img, err := letteravatar.Draw(100, ([]rune(name))[:5], opt)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		file, err := os.Create(name + ".png")
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		err = png.Encode(file, img)
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+}
+
+func loadFont(path string) (*truetype.Font, error) {
+	fontBytes, err := ioutil.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	f, err := truetype.Parse(fontBytes)
+	if err != nil {
+		return nil, err
+	}
+	return f, nil
+}

go.mod

@@ -0,0 +1,8 @@
+module github.com/disintegration/letteravatar
+
+go 1.14
+
+require (
+	github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0
+	golang.org/x/image v0.0.0-20211028202545-6944b10bf410
+)

go.sum

@@ -0,0 +1,6 @@
+github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 h1:DACJavvAHhabrF08vX0COfcOBJRhZ8lUbR+ZWIs0Y5g=
+github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0/go.mod h1:E/TSTwGwJL78qG/PmXZO1EjYhfJinVAhrmmHX6Z8B9k=
+golang.org/x/image v0.0.0-20211028202545-6944b10bf410 h1:hTftEOvwiOq2+O8k2D5/Q7COC7k5Qcrgc2TFURJYnvQ=
+golang.org/x/image v0.0.0-20211028202545-6944b10bf410/go.mod h1:023OzeP/+EPmXeapQh35lcL3II3LrY8Ic+EFFKVhULM=
+golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=