Added captcha Config

Author: feiin

canvas.go

@@ -2,14 +2,16 @@ package captcha
 
 import (
 	// "fmt"
+	"image"
+	"image/draw"
 
 	"embed"
 	// "fmt"
 	"github.com/golang/freetype"
 	"github.com/golang/freetype/truetype"
-	"image"
+	// "image"
 	"image/color"
-	// "math"
+	"math"
 	"math/rand"
 	"time"
 )
@@ -33,6 +35,13 @@ type Canvas struct {
 	*image.NRGBA
 	Width  int
 	Height int
+	Config Config
+}
+
+//DrawBackgroud 设置画板背景
+func (c *Canvas) DrawBackgroud() {
+	backgroupColor := image.NewUniform(c.Config.BackgroupColor)
+	draw.Draw(c, c.Bounds(), backgroupColor, image.ZP, draw.Over)
 }
 
 func (c *Canvas) DrawLines(lineCount int) {
@@ -51,12 +60,12 @@ func (c *Canvas) DrawLines(lineCount int) {
 func (c *Canvas) DrawLine(p1, p2 Point, color color.Color) {
 
 	var k float64 = 0
-	b := p1.Y
+	var b float64 = 0
 	if (p2.X - p1.X) != 0 {
 		k = float64(p2.Y-p1.Y) / float64(p2.X-p1.X)
 	}
 
-	b = p1.Y - int(k*float64(p1.X))
+	b = float64(p1.Y) - k*float64(p1.X)
 
 	sx := 1
 	offsetX := p1.X
@@ -65,9 +74,32 @@ func (c *Canvas) DrawLine(p1, p2 Point, color color.Color) {
 		sx = -1
 	}
 
+	if k == 0 && p2.X == p1.X {
+
+		tmpY := p1.Y
+
+		if p2.Y < p1.Y {
+			sx = -1
+		}
+
+		for {
+
+			c.Set(offsetX, tmpY, color)
+
+			if tmpY == p2.Y {
+				break
+			}
+
+			tmpY = tmpY + sx
+
+		}
+
+		return
+	}
+
 	for {
 
-		offsetY := int(k*float64(offsetX)) + b
+		offsetY := int(k*float64(offsetX) + b)
 		c.Set(offsetX, offsetY, color)
 
 		if offsetX == p2.X {
@@ -78,32 +110,180 @@ func (c *Canvas) DrawLine(p1, p2 Point, color color.Color) {
 	}
 }
 
+//DrawBezierLines 画贝塞尔干扰线
+func (c *Canvas) DrawBezierLines(lineCount int) {
+
+	for lineCount > 0 {
+
+		lineColor := randomColor()
+
+		x1 := rand.Intn(c.Width / 4)
+		y1 := randomInt(c.Height/4, int(float64(c.Height)*0.9))
+
+		x2 := randomInt(c.Width/2, int(float64(c.Width)*0.9))
+		y2 := randomInt(c.Height/4, int(float64(c.Height)*0.9))
+
+		cx := randomInt(c.Width/4, int(float64(c.Width)*0.7))
+		cy := randomInt(c.Height/4, int(float64(c.Height)*0.6))
+
+		// B(t) = (1-t)P0 + 2t(1-t)P1 + tP2,   t∈[0,1]
+		// x = Math.pow(1-t, 2) * x1 + 2 * t * (1-t) * cx + Math.pow(t, 2) * x2
+		// y = Math.pow(1-t, 2) * y1 + 2 * t * (1-t) * cy + Math.pow(t, 2) * y2
+		var t float64
+		for t < 1 {
+
+			x := math.Pow(1-t, 2.0)*float64(x1) + 2*t*(1-t)*float64(cx) + math.Pow(t, 2.0)*float64(x2)
+			y := math.Pow(1-t, 2)*float64(y1) + 2*t*(1-t)*float64(cy) + math.Pow(t, 2)*float64(y2)
+
+			c.Set(int(x), int(y), lineColor)
+			t = t + 0.001
+		}
+
+		lineCount--
+	}
+
+}
+
 func (c *Canvas) DrawString(text string) {
 
+	var drawPos []DrawPos
 	for _, ch := range text {
 
-		dc := freetype.NewContext()
-		dc.SetDPI(float64(72))
-		dc.SetFont(defaultFont)
-		dc.SetClip(c.Bounds())
-		dc.SetDst(c)
+		pos := c.randomFontPosition(56)
 
-		// 文字大小
-		dc.SetFontSize(float64(56))
+		fontImg, areaPoint := c.DrawFont(string(ch), c.Config.FrontColors)
+
+		minX := areaPoint.MinX
+		maxX := areaPoint.MaxX
+		minY := areaPoint.MinY
+		maxY := areaPoint.MaxY
+		width := maxX - minX
+		height := maxY - minY
+		nW := fontImg.Bounds().Max.X
+		nH := fontImg.Bounds().Max.Y
+		for x := 0; x < nW; x++ {
+			for y := 0; y < nH; y++ {
+				co := fontImg.At(x, y)
+				if _, _, _, a := co.RGBA(); a > 0 {
+					if x >= minX && x <= maxX && y >= minY && y <= maxY {
+						c.Set(pos.X+(x-minX), pos.Y-height+(y-minY), fontImg.At(x, y))
+					}
+				}
+			}
+		}
 
-		// 文字颜色
-		fontColor := image.NewUniform(randomColor())
-		dc.SetSrc(fontColor)
+		var dp DrawPos
+		dp.X = minX + pos.X
+		dp.Y = pos.Y - height
+		dp.Width = width
+		dp.Height = height
 
-		pos := c.randomFontPosition(56)
-		// 画文本
-		pt := freetype.Pt(pos.X, pos.Y) // 字出现的位置
-		_, err := dc.DrawString(string(ch), pt)
-		if err != nil {
-			panic(err)
+		drawPos = append(drawPos, dp)
+
+	}
+
+	// lineColor := randomColor()
+
+	// for _, linePos := range drawPos {
+	// 	p1 := Point{X: linePos.X, Y: linePos.Y}
+	// 	p2 := Point{X: linePos.X + linePos.Width, Y: linePos.Y}
+
+	// 	p3 := Point{X: linePos.X, Y: linePos.Y + linePos.Height}
+	// 	p4 := Point{X: linePos.X + linePos.Width, Y: linePos.Y + linePos.Height}
+	// 	c.DrawLine(p1, p2, lineColor)
+	// 	c.DrawLine(p1, p3, lineColor)
+	// 	c.DrawLine(p3, p4, lineColor)
+	// 	c.DrawLine(p2, p4, lineColor)
+
+	// }
+	// fmt.Printf("drawpos %+v %s", drawPos, text)
+
+}
+
+//DrawFont 绘制验证码字
+func (c *Canvas) DrawFont(fontText string, fontColors []color.Color) (*Palette, *AreaPoint) {
+	fontSize := 56
+
+	rand.Seed(time.Now().UnixNano())
+
+	fntColorIndex := rand.Intn(len(fontColors))
+
+	rColor := fontColors[fntColorIndex]
+	p := []color.Color{
+		color.RGBA{R: 0xFF, G: 0xFF, B: 0xFF, A: 0x00},
+		rColor,
+	}
+
+	canvas := NewPalette(image.Rect(0, 0, fontSize, fontSize), p)
+
+	dc := freetype.NewContext()
+	dc.SetDPI(float64(72))
+	dc.SetFont(defaultFont)
+	dc.SetClip(canvas.Bounds())
+	dc.SetDst(canvas)
+
+	// 文字大小
+	dc.SetFontSize(float64(56))
+
+	// 文字颜色
+	fontColor := image.NewUniform(rColor)
+	dc.SetSrc(fontColor)
+
+	// 画文本
+	pt := freetype.Pt(0, fontSize) // 字出现的位置
+	_, err := dc.DrawString(string(fontText), pt)
+
+	if err != nil {
+		panic(err)
+	}
+
+	//旋转角度
+	canvas.Rotate(randomInt(-30, 30))
+	ap := c.calcImageSpace(canvas)
+	return canvas, ap
+
+}
+
+func (c *Canvas) calcImageSpace(pa *Palette) *AreaPoint {
+	nW := pa.Bounds().Max.X
+	nH := pa.Bounds().Max.Y
+	// 计算裁剪的最小及最大的坐标
+	minX := nW
+	maxX := 0
+	minY := nH
+	maxY := 0
+	for x := 0; x < nW; x++ {
+		for y := 0; y < nH; y++ {
+			co := pa.At(x, y)
+			if _, _, _, a := co.RGBA(); a > 0 {
+				if x < minX {
+					minX = x
+				}
+				if x > maxX {
+					maxX = x
+				}
+
+				if y < minY {
+					minY = y
+				}
+				if y > maxY {
+					maxY = y
+				}
+			}
 		}
 	}
 
+	minX = int(math.Max(0, float64(minX-2)))
+	maxX = int(math.Min(float64(nW), float64(maxX+2)))
+	minY = int(math.Max(0, float64(minY-2)))
+	maxY = int(math.Min(float64(nH), float64(maxY+2)))
+
+	return &AreaPoint{
+		minX,
+		maxX,
+		minY,
+		maxY,
+	}
 }
 
 func (c *Canvas) randomFontPosition(fontSize int) Point {

captcha.go

@@ -5,33 +5,76 @@ import (
 	"encoding/base64"
 	"fmt"
 	"image"
-	// "image/color"
+	"image/color"
 	"image/png"
 	"os"
 )
 
+type Config struct {
+	FrontColors    []color.Color
+	BackgroupColor color.Color
+}
+
 type Captcha struct {
 	Width  int
 	Height int
+	Config Config
 }
 
 func NewCaptcha(width, height int) *Captcha {
-	return &Captcha{Width: width, Height: height}
+	cp := Captcha{Width: width, Height: height}
+
+	config := Config{}
+	config.FrontColors = []color.Color{
+		color.RGBA{R: uint8(66), G: uint8(153), B: uint8(244), A: uint8(255)},
+		color.RGBA{R: uint8(234), G: uint8(67), B: uint8(53), A: uint8(255)},
+		color.RGBA{R: uint8(251), G: uint8(188), B: uint8(5), A: uint8(255)},
+		color.RGBA{R: uint8(52), G: uint8(168), B: uint8(83), A: uint8(255)},
+	}
+	config.BackgroupColor = color.White
+
+	cp.Config = config
+	return &cp
+
+}
+
+//SetFontColors 设置字体颜色
+func (cp *Captcha) SetFontColors(colors ...color.Color) {
+	if len(colors) == 0 {
+		return
+	}
+
+	cp.Config.FrontColors = cp.Config.FrontColors[:0]
+	for _, cr := range colors {
+		cp.Config.FrontColors = append(cp.Config.FrontColors, cr)
+	}
+
+}
+
+//SetBackgroundColor 设置背景颜色
+func (cp *Captcha) SetBackgroundColor(color color.Color) {
+	cp.Config.BackgroupColor = color
 }
 
 func (cp *Captcha) GenCaptchaImage() (string, error) {
+
 	c := Canvas{
 		Width:  cp.Width,
 		Height: cp.Height,
 		NRGBA:  image.NewNRGBA(image.Rect(0, 0, cp.Width, cp.Height)),
+		Config: cp.Config,
 	}
 
+	c.DrawBackgroud()
+
 	c.DrawLines(5)
 
-	c.DrawString("测试阿斯蒂")
+	c.DrawString("3567中")
 
 	c.DrawCircles(120)
 
+	// c.DrawBezierLines(5)
+
 	imageBytes, err := encodingWithPng(c)
 
 	if err != nil {

captcha_test.go

@@ -1,12 +1,15 @@
 package captcha
 
 import (
+	"image/color"
 	"testing"
 )
 
 func TestGenCaptcha(t *testing.T) {
 
 	cpt := NewCaptcha(460, 200)
+	cpt.SetBackgroundColor(color.RGBA{R: uint8(20), G: uint8(8), B: uint8(100), A: uint8(255)})
+
 	image, err := cpt.GenCaptchaImage()
 	t.Logf("GenCaptchaImage %s %+v", image, err)
 }