status-im/status-go

package images

import (
    "bytes"
    "image/color"
    "image/png"
    "io/ioutil"
    "strings"

    "github.com/fogleman/gg"
    "golang.org/x/image/font"
    "golang.org/x/image/font/opentype"
)

type RGBA struct {
    R, G, B, A float64
}

var parsedFont *opentype.Font = nil

func ExtractInitials(fullName string, amountInitials int) string {
    if fullName == "" {
        return ""
    }
    var initials strings.Builder
    namesList := strings.Fields(fullName)
    for _, name := range namesList {
        if len(initials.String()) >= amountInitials {
            break
        }
        if name != "" {
            initials.WriteString(strings.ToUpper(name[0:1]))
        }
    }
    return initials.String()
}

// GenerateInitialsImage uppercaseRatio is <height of any upper case> / dc.FontHeight() (line height)
// 0.60386123 for Inter-UI-Medium.otf
func GenerateInitialsImage(initials string, bgColor, fontColor color.Color, fontFile string, size int, fontSize float64, uppercaseRatio float64) ([]byte, error) {
    // Load otf file
    fontBytes, err := ioutil.ReadFile(fontFile)
    if err != nil {
        return nil, err
    }

    if parsedFont == nil {
        parsedFont, err = opentype.Parse(fontBytes)
        if err != nil {
            return nil, err
        }
    }

    halfSize := float64(size / 2)

    dc := gg.NewContext(size, size)
    dc.DrawCircle(halfSize, halfSize, halfSize)
    dc.SetColor(bgColor)
    dc.Fill()

    // Load font
    face, err := opentype.NewFace(parsedFont, &opentype.FaceOptions{
        Size:    fontSize,
        DPI:     72,
        Hinting: font.HintingNone,
    })
    if err != nil {
        return nil, err
    }
    dc.SetFontFace(face)

    // Draw initials
    dc.SetColor(fontColor)

    dc.DrawStringAnchored(initials, halfSize, halfSize, 0.5, uppercaseRatio/2)

    img := dc.Image()
    buffer := new(bytes.Buffer)
    err = png.Encode(buffer, img)
    if err != nil {
        return nil, err
    }
    return buffer.Bytes(), nil
}