119 lines
2.9 KiB
Go
119 lines
2.9 KiB
Go
package vision
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import (
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"image/color"
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"math"
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"apigo.cc/go/rand"
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)
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// CaptchaOption 定义验证码生成选项
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type CaptchaOption struct {
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Text string
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Length int
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Width int
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Height int
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NoiseLevel int // 1-10
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}
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// GenerateCaptcha 生成一个验证码画布
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func GenerateCaptcha(opt *CaptchaOption) *Canvas {
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if opt == nil { opt = &CaptchaOption{} }
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if opt.Length == 0 { opt.Length = 4 }
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if opt.Width == 0 { opt.Width = 150 }
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if opt.Height == 0 { opt.Height = 50 }
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if opt.NoiseLevel == 0 { opt.NoiseLevel = 3 }
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if opt.Text == "" {
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chars := "ABCDEFGHJKMNPQRSTWXYZabcdefhijkmnpqrstwxyz2345678"
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text := make([]byte, opt.Length)
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for i := 0; i < opt.Length; i++ {
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text[i] = chars[rand.Int(0, len(chars)-1)]
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}
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opt.Text = string(text)
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}
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c := New(opt.Width, opt.Height, "#FFFFFF")
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c.RandBG(opt.NoiseLevel)
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// 计算字体大小
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fontSize := math.Max(28, float64(opt.Height)*0.7)
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_ = c.SetFont(fontSize)
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// 绘制随机扭曲文本
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c.RandText(opt.Text)
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return c
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}
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// GenerateGIFCaptcha 生成动态 GIF 验证码
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func GenerateGIFCaptcha(opt *CaptchaOption) *Animation {
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if opt == nil {
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opt = &CaptchaOption{Length: 4, Width: 120, Height: 40}
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}
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const chars = "0123456789"
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code := ""
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for i := 0; i < opt.Length; i++ {
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code += string(chars[rand.Int(0, len(chars)-1)])
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}
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anim := NewAnimation()
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// 每一帧显示不同的干扰和字符位移
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for i := 0; i < 10; i++ {
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c := New(opt.Width, opt.Height, "#FFFFFF")
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c.RandBG(3)
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// 绘制字符，每一帧字符的位置都有微小抖动
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for idx, char := range code {
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x := float64(idx)*float64(opt.Width/opt.Length) + 5 + rand.Float(0.0, 4.0) - 2.0
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y := float64(opt.Height/2) + 10 + rand.Float(0.0, 6.0) - 3.0
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c.dc.Push()
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c.dc.RotateAbout(rand.Float(0.0, 0.4)-0.2, x, y)
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c.dc.SetColor(ParseColor(RandColor()))
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c.dc.DrawString(string(char), x, y)
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c.dc.Pop()
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}
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anim.AddFrame(c, 15) // 150ms 每帧
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}
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return anim
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}
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// RandText 绘制随机扭曲文本 (用于验证码)
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func (c *Canvas) RandText(text string) [][4]float64 {
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w, h := float64(c.Width()), float64(c.Height())
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fullWidth, _ := c.dc.MeasureString(text)
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x := (w - fullWidth) / 2
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y := h/2 + (c.dc.FontHeight()*0.7)/2
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charPositions := make([][4]float64, 0, len(text))
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for _, char := range text {
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charStr := string(char)
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charWidth, _ := c.dc.MeasureString(charStr)
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charHeight := c.dc.FontHeight()
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yOffset := rand.Float(0.0, 10.0) - 5
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angle := rand.Float(0.0, 0.4) - 0.2 // ±11°
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charPositions = append(charPositions, [4]float64{x, y + yOffset - charHeight, charWidth, charHeight})
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c.dc.Push()
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c.dc.RotateAbout(angle, x+charWidth/2, y+yOffset-charHeight/2)
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// 绘制阴影
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c.dc.SetColor(color.Gray{Y: 100})
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c.dc.DrawString(charStr, x+1, y+yOffset+1)
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// 绘制主体
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c.dc.SetColor(ParseColor(RandColor()))
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c.dc.DrawString(charStr, x, y+yOffset)
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c.dc.Pop()
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x += charWidth + rand.Float(0.0, 5.0)
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}
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return charPositions
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}
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