100 lines
2.4 KiB
Go
100 lines
2.4 KiB
Go
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package captcha
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import (
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"bytes"
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"github.com/fogleman/gg"
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"github.com/golang/freetype/truetype"
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"golang.org/x/image/font"
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"math/rand"
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)
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func ImgText(width, height int, text string) (b []byte) {
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textLen := len(text)
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dc := gg.NewContext(width, height)
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bgR, bgG, bgB, bgA := getRandColorRange(240, 255)
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dc.SetRGBA255(bgR, bgG, bgB, bgA)
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dc.Clear()
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// 干扰线
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for i := 0; i < 10; i++ {
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x1, y1 := getRandPos(width, height)
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x2, y2 := getRandPos(width, height)
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r, g, b, a := getRandColor(255)
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w := float64(rand.Intn(3) + 1)
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dc.SetRGBA255(r, g, b, a)
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dc.SetLineWidth(w)
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dc.DrawLine(x1, y1, x2, y2)
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dc.Stroke()
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}
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fontSize := float64(height/2) + 5
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face := loadFontFace(fontSize)
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dc.SetFontFace(face)
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for i := 0; i < len(text); i++ {
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r, g, b, _ := getRandColor(100)
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dc.SetRGBA255(r, g, b, 255)
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fontPosX := float64(width/textLen*i) + fontSize*0.6
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writeText(dc, text[i:i+1], float64(fontPosX), float64(height/2))
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}
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buffer := bytes.NewBuffer(nil)
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dc.EncodePNG(buffer)
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b = buffer.Bytes()
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return
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}
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// 渲染文字
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func writeText(dc *gg.Context, text string, x, y float64) {
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xfload := 5 - rand.Float64()*10 + x
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yfload := 5 - rand.Float64()*10 + y
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radians := 40 - rand.Float64()*80
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dc.RotateAbout(gg.Radians(radians), x, y)
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dc.DrawStringAnchored(text, xfload, yfload, 0.2, 0.5)
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dc.RotateAbout(-1*gg.Radians(radians), x, y)
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dc.Stroke()
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}
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// 随机坐标
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func getRandPos(width, height int) (x float64, y float64) {
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x = rand.Float64() * float64(width)
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y = rand.Float64() * float64(height)
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return x, y
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}
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// 随机颜色
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func getRandColor(maxColor int) (r, g, b, a int) {
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r = int(uint8(rand.Intn(maxColor)))
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g = int(uint8(rand.Intn(maxColor)))
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b = int(uint8(rand.Intn(maxColor)))
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a = int(uint8(rand.Intn(255)))
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return r, g, b, a
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}
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// 随机颜色范围
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func getRandColorRange(miniColor, maxColor int) (r, g, b, a int) {
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if miniColor > maxColor {
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miniColor = 0
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maxColor = 255
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}
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r = int(uint8(rand.Intn(maxColor-miniColor) + miniColor))
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g = int(uint8(rand.Intn(maxColor-miniColor) + miniColor))
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b = int(uint8(rand.Intn(maxColor-miniColor) + miniColor))
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a = int(uint8(rand.Intn(maxColor-miniColor) + miniColor))
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return r, g, b, a
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}
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// 加载字体
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func loadFontFace(points float64) font.Face {
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f, err := truetype.Parse(COMICSAN)
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if err != nil {
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panic(err)
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}
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face := truetype.NewFace(f, &truetype.Options{
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Size: points,
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})
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return face
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}
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