Files
1Panel/core/utils/captcha/image.go

63 lines
1.7 KiB
Go

package captcha
import (
"bytes"
"encoding/base64"
"image"
"image/color"
"image/draw"
"image/png"
"math/rand/v2"
"sync"
"golang.org/x/image/font"
"golang.org/x/image/font/gofont/gobold"
"golang.org/x/image/font/opentype"
"golang.org/x/image/math/fixed"
)
var loadFont = sync.OnceValues(func() (*opentype.Font, error) {
return opentype.Parse(gobold.TTF)
})
func renderQuestion(question string) (string, error) {
f, err := loadFont()
if err != nil {
return "", err
}
dst := image.NewRGBA(image.Rect(0, 0, captchaWidth, captchaHeight))
background := image.NewUniform(color.RGBA{R: 246, G: 248, B: 251, A: 255})
draw.Draw(dst, dst.Bounds(), background, image.Point{}, draw.Src)
chars := []rune(question)
cellWidth := (captchaWidth - 12) / len(chars)
for i, char := range chars {
face, err := opentype.NewFace(f, &opentype.FaceOptions{
Size: float64(24 + rand.IntN(5)), DPI: 72, Hinting: font.HintingFull,
})
if err != nil {
return "", err
}
bounds, _ := font.BoundString(face, string(char))
x := fixed.I(6+i*cellWidth+cellWidth/2) - (bounds.Min.X+bounds.Max.X)/2
y := fixed.I(captchaHeight/2+rand.IntN(7)-3) - (bounds.Min.Y+bounds.Max.Y)/2
d := font.Drawer{
Dst: dst,
Src: image.NewUniform(color.RGBA{
R: uint8(20 + rand.IntN(90)), G: uint8(20 + rand.IntN(90)),
B: uint8(20 + rand.IntN(90)), A: 255,
}),
Face: face,
Dot: fixed.Point26_6{X: x, Y: y},
}
d.DrawString(string(char))
if err := face.Close(); err != nil {
return "", err
}
}
var buf bytes.Buffer
if err := png.Encode(&buf, dst); err != nil {
return "", err
}
return "data:image/png;base64," + base64.StdEncoding.EncodeToString(buf.Bytes()), nil
}