340 lines
8.2 KiB
Go
340 lines
8.2 KiB
Go
package captcha
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import (
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"crypto/rand"
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"github.com/golang/freetype"
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"github.com/llgcode/draw2d"
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"github.com/llgcode/draw2d/draw2dimg"
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"image"
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"image/color"
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"log"
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"math"
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"math/big"
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"os"
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"path/filepath"
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"strconv"
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)
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const (
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chars = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
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operator = "+-*/"
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defaultLen = 4
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defaultFontSize = 20
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defaultDpi = 72
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)
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// Captcha 图形验证码 使用字体默认ttf格式
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// w 图片宽度, h图片高度，CodeLen验证码的个数
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// FontSize 字体大小, Dpi 清晰度，FontPath 字体目录， FontName 字体名字
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// mode 验证模式 0：普通字符串，1：10以内简单数学公式
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type Captcha struct {
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W, H, CodeLen int
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FontSize float64
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Dpi int
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FontPath, FontName string
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mode int
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}
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// NewCaptcha 实例化验证码
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func NewCaptcha(w, h, CodeLen int) *Captcha {
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return &Captcha{W: w, H: h, CodeLen: CodeLen}
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}
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// OutPut 输出
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func (captcha *Captcha) OutPut() (string, *image.RGBA) {
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img := captcha.initCanvas()
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return captcha.doImage(img)
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}
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// RangeRand 获取区间[-m, n]的随机数
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func (captcha *Captcha) RangeRand(min, max int64) int64 {
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if min > max {
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panic("the min is greater than max!")
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}
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if min < 0 {
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f64Min := math.Abs(float64(min))
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i64Min := int64(f64Min)
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result, _ := rand.Int(rand.Reader, big.NewInt(max+1+i64Min))
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return result.Int64() - i64Min
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} else {
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result, _ := rand.Int(rand.Reader, big.NewInt(max-min+1))
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return min + result.Int64()
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}
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}
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// 随机字符串
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func (captcha *Captcha) getRandCode() string {
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if captcha.CodeLen <= 0 {
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captcha.CodeLen = defaultLen
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}
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var code = ""
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for l := 0; l < captcha.CodeLen; l++ {
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charsPos := captcha.RangeRand(0, int64(len(chars)-1))
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code += string(chars[charsPos])
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}
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return code
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}
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// 获取算术运算公式
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func (captcha *Captcha) getFormulaMixData() (string, []string) {
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num1 := int(captcha.RangeRand(11, 20))
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num2 := int(captcha.RangeRand(1, 10))
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opArr := []rune(operator)
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opRand := opArr[captcha.RangeRand(0, 3)]
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strNum1 := strconv.Itoa(num1)
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strNum2 := strconv.Itoa(num2)
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var ret int
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var opRet string
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switch string(opRand) {
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case "+":
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ret = num1 + num2
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opRet = "+"
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case "-":
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if num1-num2 > 0 {
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ret = num1 - num2
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opRet = "-"
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} else {
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ret = num1 + num2
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opRet = "+"
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}
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case "*":
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if num1*num2 < 100 {
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ret = num1 * num2
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//opRet = "×"
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opRet = "×"
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} else {
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ret = num1 + num2
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opRet = "+"
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}
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case "/":
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if num1%num2 == 0 {
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ret = num1 / num2
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opRet = "÷"
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} else {
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ret = num1 + num2
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opRet = "+"
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}
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}
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return strconv.Itoa(ret), []string{strNum1, opRet, strNum2, "=", "?"}
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}
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// 初始化画布
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func (captcha *Captcha) initCanvas() *image.RGBA {
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dest := image.NewRGBA(image.Rect(0, 0, captcha.W, captcha.H))
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// 随机色
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r := uint8(255) // uint8(captcha.RangeRand(50, 250))
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g := uint8(255) // uint8(captcha.RangeRand(50, 250))
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b := uint8(255) // uint8(captcha.RangeRand(50, 250))
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// 填充背景色
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for x := 0; x < captcha.W; x++ {
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for y := 0; y < captcha.H; y++ {
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dest.Set(x, y, color.RGBA{R: r, G: g, B: b, A: 255}) //设定alpha图片的透明度
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}
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}
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return dest
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}
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// 处理图像
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func (captcha *Captcha) doImage(dest *image.RGBA) (string, *image.RGBA) {
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gc := draw2dimg.NewGraphicContext(dest)
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defer gc.Close()
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defer gc.FillStroke()
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captcha.setFont(gc)
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captcha.doPoint(gc)
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captcha.doLine(gc)
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captcha.doSinLine(gc)
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var codeStr string
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if captcha.mode == 1 {
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ret, formula := captcha.getFormulaMixData()
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// log.Println("算数验证码: ", formula)
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codeStr = ret
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captcha.doFormula(gc, formula)
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} else {
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codeStr = captcha.getRandCode()
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captcha.doCode(gc, codeStr)
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}
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return codeStr, dest
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}
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// 验证码字符设置到图像上
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func (captcha *Captcha) doCode(gc *draw2dimg.GraphicContext, code string) {
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for l := 0; l < len(code); l++ {
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y := captcha.RangeRand(int64(captcha.FontSize)-1, int64(captcha.H)+6)
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x := captcha.RangeRand(1, 20)
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// 随机色
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r := uint8(captcha.RangeRand(0, 200))
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g := uint8(captcha.RangeRand(0, 200))
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b := uint8(captcha.RangeRand(0, 200))
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gc.SetFillColor(color.RGBA{R: r, G: g, B: b, A: 255})
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gc.FillStringAt(string(code[l]), float64(x)+captcha.FontSize*float64(l), float64(int64(captcha.H)-y)+captcha.FontSize)
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gc.Stroke()
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}
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}
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// 验证码字符设置到图像上
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func (captcha *Captcha) doFormula(gc *draw2dimg.GraphicContext, formulaArr []string) {
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for l := 0; l < len(formulaArr); l++ {
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y := captcha.RangeRand(0, 10)
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x := captcha.RangeRand(5, 10)
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// 随机色
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r := uint8(captcha.RangeRand(10, 200))
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g := uint8(captcha.RangeRand(10, 200))
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b := uint8(captcha.RangeRand(10, 200))
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gc.SetFillColor(color.RGBA{R: r, G: g, B: b, A: 255})
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gc.FillStringAt(formulaArr[l], float64(x)+captcha.FontSize*float64(l), captcha.FontSize+float64(y))
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gc.Stroke()
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}
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}
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// 增加干扰线
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func (captcha *Captcha) doLine(gc *draw2dimg.GraphicContext) {
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// 设置干扰线
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for n := 0; n < 3; n++ {
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gc.SetLineWidth(float64(captcha.RangeRand(1, 2)))
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//gc.SetLineWidth(1)
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// 随机背景色
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r := uint8(captcha.RangeRand(0, 255))
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g := uint8(captcha.RangeRand(0, 255))
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b := uint8(captcha.RangeRand(0, 255))
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gc.SetStrokeColor(color.RGBA{R: r, G: g, B: b, A: 255})
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// 初始化位置
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gc.MoveTo(float64(captcha.RangeRand(0, int64(captcha.W)+10)), float64(captcha.RangeRand(0, int64(captcha.H)+5)))
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gc.LineTo(float64(captcha.RangeRand(0, int64(captcha.W)+10)), float64(captcha.RangeRand(0, int64(captcha.H)+5)))
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gc.Stroke()
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}
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}
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// 增加干扰点
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func (captcha *Captcha) doPoint(gc *draw2dimg.GraphicContext) {
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for n := 0; n < 10; n++ {
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gc.SetLineWidth(float64(captcha.RangeRand(1, 3)))
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// 随机色
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r := uint8(captcha.RangeRand(0, 255))
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g := uint8(captcha.RangeRand(0, 255))
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b := uint8(captcha.RangeRand(0, 255))
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gc.SetStrokeColor(color.RGBA{R: r, G: g, B: b, A: 255})
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x := captcha.RangeRand(0, int64(captcha.W)+10) + 1
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y := captcha.RangeRand(0, int64(captcha.H)+5) + 1
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gc.MoveTo(float64(x), float64(y))
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gc.LineTo(float64(x+captcha.RangeRand(1, 2)), float64(y+captcha.RangeRand(1, 2)))
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gc.Stroke()
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}
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}
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// 增加正弦干扰线
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func (captcha *Captcha) doSinLine(gc *draw2dimg.GraphicContext) {
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h1 := captcha.RangeRand(-12, 12)
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h2 := captcha.RangeRand(-1, 1)
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w2 := captcha.RangeRand(5, 20)
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h3 := captcha.RangeRand(5, 10)
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h := float64(captcha.H)
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w := float64(captcha.W)
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// 随机色
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r := uint8(captcha.RangeRand(128, 255))
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g := uint8(captcha.RangeRand(128, 255))
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b := uint8(captcha.RangeRand(128, 255))
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gc.SetStrokeColor(color.RGBA{R: r, G: g, B: b, A: 255})
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gc.SetLineWidth(float64(captcha.RangeRand(1, 2)))
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var i float64
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for i = -w / 2; i < w/2; i = i + 0.1 {
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y := h/float64(h3)*math.Sin(i/float64(w2)) + h/2 + float64(h1)
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gc.LineTo(i+w/2, y)
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if h2 == 0 {
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gc.LineTo(i+w/2, y+float64(h2))
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}
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}
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gc.Stroke()
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}
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// SetMode 设置模式
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func (captcha *Captcha) SetMode(mode int) {
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captcha.mode = mode
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}
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// SetFontPath 设置字体路径
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func (captcha *Captcha) SetFontPath(FontPath string) {
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captcha.FontPath = FontPath
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}
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// SetFontName 设置字体名称
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func (captcha *Captcha) SetFontName(FontName string) {
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captcha.FontName = FontName
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}
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// SetFontSize 设置字体大小
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func (captcha *Captcha) SetFontSize(fontSize float64) {
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captcha.FontSize = fontSize
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}
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// 设置相关字体
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func (captcha *Captcha) setFont(gc *draw2dimg.GraphicContext) {
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if captcha.FontPath == "" {
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panic("the font path is empty!")
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}
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if captcha.FontName == "" {
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panic("the font name is empty!")
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}
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// 字体文件
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fontFile := filepath.Join(captcha.FontPath, captcha.FontName+".ttf")
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fontBytes, err := os.ReadFile(fontFile)
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if err != nil {
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log.Println(err)
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return
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}
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font, err := freetype.ParseFont(fontBytes)
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if err != nil {
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log.Println(err)
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return
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}
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// 设置自定义字体相关信息
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gc.FontCache = draw2d.NewSyncFolderFontCache(captcha.FontPath)
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gc.FontCache.Store(draw2d.FontData{Name: captcha.FontName, Family: 0, Style: draw2d.FontStyleNormal}, font)
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gc.SetFontData(draw2d.FontData{Name: captcha.FontName, Style: draw2d.FontStyleNormal})
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//设置清晰度
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if captcha.Dpi <= 0 {
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captcha.Dpi = defaultDpi
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}
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gc.SetDPI(captcha.Dpi)
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// 设置字体大小
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if captcha.FontSize <= 0 {
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captcha.FontSize = defaultFontSize
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}
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gc.SetFontSize(captcha.FontSize)
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}
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