Started work on code cleanup.

Makefile

@@ -3,7 +3,6 @@ include $(GOROOT)/src/Make.inc
 TARG=github.com/dchest/captcha
 GOFILES=\
 	captcha.go\
-	draw.go\
 	font.go\
 	image.go
 

captcha.go

@@ -2,7 +2,6 @@ package captcha
 
 import (
 	"bytes"
-	"image/png"
 	"os"
 	"rand"
 	"time"
@@ -14,8 +13,6 @@ import (
 )
 
 const (
-	dotSize    = 6
-	maxSkew    = 3
 	expiration = 2 * 60 // 2 minutes
 	collectNum = 100    // number of items that triggers collection
 )
@@ -47,7 +44,7 @@ func init() {
 }
 
 func randomNumbers() []byte {
-	n := make([]byte, 6)
+	n := make([]byte, 3)
 	if _, err := io.ReadFull(crand.Reader, n); err != nil {
 		panic(err)
 	}
@@ -72,14 +69,14 @@ func New() string {
 	return id
 }
 
-func WriteImage(w io.Writer, id string) os.Error {
+func WriteImage(w io.Writer, id string, width, height int) os.Error {
 	store.mu.RLock()
 	defer store.mu.RUnlock()
 	ns, ok := store.ids[id]
 	if !ok {
 		return os.NewError("captcha id not found")
 	}
-	return png.Encode(w, NewImage(ns))
+	return NewImage(ns, width, height).PNGEncode(w)
 }
 
 func Verify(w io.Writer, id string, ns []byte) bool {

cmd/main.go

@@ -6,5 +6,6 @@ import (
 )
 
 func main() {
-	captcha.EncodeNewImage(os.Stdout)
+	img, _ := captcha.NewRandomImage(300, 80)
+	img.PNGEncode(os.Stdout)
 }

draw.go

@@ -1,118 +0,0 @@
-package captcha
-
-import (
-	"image"
-	"rand"
-)
-
-func drawHorizLine(img *image.NRGBA, color image.Color, fromX, toX, y int) {
-	for x := fromX; x <= toX; x++ {
-		img.Set(x, y, color)
-	}
-}
-
-func drawCircle(img *image.NRGBA, color image.Color, x0, y0, radius int) {
-	f := 1 - radius
-	ddFx := 1
-	ddFy := -2 * radius
-	x := 0
-	y := radius
-
-	img.Set(x0, y0+radius, color)
-	img.Set(x0, y0-radius, color)
-	drawHorizLine(img, color, x0-radius, x0+radius, y0)
-
-	for x < y {
-		if f >= 0 {
-			y--
-			ddFy += 2
-			f += ddFy
-		}
-		x++
-		ddFx += 2
-		f += ddFx
-		drawHorizLine(img, color, x0-x, x0+x, y0+y)
-		drawHorizLine(img, color, x0-x, x0+x, y0-y)
-		drawHorizLine(img, color, x0-y, x0+y, y0+x)
-		drawHorizLine(img, color, x0-y, x0+y, y0-x)
-	}
-}
-
-
-func min3(x, y, z uint8) (o uint8) {
-	o = x
-	if y < o {
-		o = y
-	}
-	if z < o {
-		o = z
-	}
-	return
-}
-
-func max3(x, y, z uint8) (o uint8) {
-	o = x
-	if y > o {
-		o = y
-	}
-	if z > o {
-		o = z
-	}
-	return
-}
-
-func setRandomBrightness(c *image.NRGBAColor, max uint8) {
-	minc := min3(c.R, c.G, c.B)
-	maxc := max3(c.R, c.G, c.B)
-	if maxc > max {
-		return
-	}
-	n := rand.Intn(int(max-maxc)) - int(minc)
-	c.R = uint8(int(c.R) + n)
-	c.G = uint8(int(c.G) + n)
-	c.B = uint8(int(c.B) + n)
-}
-
-func fillWithCircles(img *image.NRGBA, color image.NRGBAColor, n, maxradius int) {
-	maxx := img.Bounds().Max.X
-	maxy := img.Bounds().Max.Y
-	for i := 0; i < n; i++ {
-		setRandomBrightness(&color, 255)
-		r := rand.Intn(maxradius-1) + 1
-		drawCircle(img, color, rand.Intn(maxx-r*2)+r, rand.Intn(maxy-r*2)+r, r)
-	}
-}
-
-func drawCirclesLine(img *image.NRGBA, color image.Color) {
-	r := 0
-	maxx := img.Bounds().Max.X
-	maxy := img.Bounds().Max.Y
-	y := rand.Intn(maxy/2+maxy/3) - rand.Intn(maxy/3)
-	for x := 0; x < maxx; x += r  {
-		r = rand.Intn(dotSize/2)
-		y += rand.Intn(3) - 1
-		if y <= 0 || y >= maxy {
-			y = rand.Intn(maxy/2) + rand.Intn(maxy/2)
-		}
-		drawCircle(img, color, x, y, r)
-	}
-}
-
-func drawNumber(img *image.NRGBA, number []byte, x, y int, color image.NRGBAColor) {
-	skf := rand.Intn(maxSkew) - maxSkew/2
-	if skf < 0 {
-		x -= skf * numberHeight
-	}
-	for y0 := 0; y0 < numberHeight; y0++ {
-		for x0 := 0; x0 < numberWidth; x0++ {
-			radius := rand.Intn(dotSize/2) + dotSize/2
-			addx := rand.Intn(radius / 4)
-			addy := rand.Intn(radius / 4)
-			if number[y0*numberWidth+x0] == 1 {
-				drawCircle(img, color, x+x0*dotSize+dotSize+addx,
-					y+y0*dotSize+dotSize+addy, radius)
-			}
-		}
-		x += skf
-	}
-}

font.go

@@ -1,8 +1,8 @@
 package captcha
 
 const (
-	numberWidth  = 5
-	numberHeight = 8
+	fontWidth  = 5
+	fontHeight = 8
 )
 
 var font = [][]byte{

image.go

@@ -8,28 +8,184 @@ import (
 	"rand"
 )
 
+const (
+	maxSkew = 3
+)
+
+type CaptchaImage struct {
+	*image.NRGBA
+	primaryColor image.NRGBAColor
+	numberWidth  int
+	dotRadius    int
+}
 
-func NewImage(numbers []byte) *image.NRGBA {
-	w := numberWidth * (dotSize + 3) * len(numbers)
-	h := numberHeight * (dotSize + 5)
-	img := image.NewNRGBA(w, h)
-	color := image.NRGBAColor{uint8(rand.Intn(50)), uint8(rand.Intn(50)), uint8(rand.Intn(128)), 0xFF}
-	fillWithCircles(img, color, 40, 4)
-	x := rand.Intn(dotSize)
-	y := 0
-	setRandomBrightness(&color, 180)
+func NewImage(numbers []byte, width, height int) *CaptchaImage {
+	img := new(CaptchaImage)
+	img.NRGBA = image.NewNRGBA(width, height)
+	img.primaryColor = image.NRGBAColor{uint8(rand.Intn(50)), uint8(rand.Intn(50)), uint8(rand.Intn(128)), 0xFF}
+	//width -= 30
+	//height -= 30
+	var border int = 0
+	// if width < height {
+	// 	border = width/4
+	// } else {
+	// 	border = height/4
+	// }
+	bwidth := width - border*2
+	bheight := height - border*2
+	//border := 15
+	//fullNumberWidth := int(float64(width/len(numbers)) *
+	//	float64(fontWidth) / float64(fontHeight))
+	var fullNumberWidth int
+	if float64(fontWidth)/float64(fontHeight) > float64(bwidth)/float64(bheight) {
+		fullNumberWidth	= bheight / fontHeight * fontWidth
+	} else {
+		fullNumberWidth = bwidth / len(numbers)
+	}
+	// add spacing
+	img.numberWidth = fullNumberWidth - fullNumberWidth/fontWidth
+	// center numbers in image
+	x := border
+	y := border
+	setRandomBrightness(&img.primaryColor, 180)
 	for _, n := range numbers {
-		y = rand.Intn(dotSize * 4)
-		drawNumber(img, font[n], x, y, color)
-		x += dotSize*numberWidth + rand.Intn(maxSkew) + 8
+		//y = rand.Intn(dotSize * 4)
+		img.drawNumber(font[n], x, y)
+		x += fullNumberWidth
 	}
-	drawCirclesLine(img, color)
+	//img.strikeThrough(img.primaryColor)
 	return img
 }
 
-func EncodeNewImage(w io.Writer) (numbers []byte, err os.Error) {
+func NewRandomImage(width, height int) (img *CaptchaImage, numbers []byte) {
 	numbers = randomNumbers()
-	err = png.Encode(w, NewImage(numbers))
+	img = NewImage(numbers, width, height)
+	return
+}
+
+func (img *CaptchaImage) PNGEncode(w io.Writer) os.Error {
+	return png.Encode(w, img)
+}
+
+func (img *CaptchaImage) drawHorizLine(color image.Color, fromX, toX, y int) {
+	for x := fromX; x <= toX; x++ {
+		img.Set(x, y, color)
+	}
+}
+
+func (img *CaptchaImage) drawCircle(color image.Color, x, y, radius int) {
+	f := 1 - radius
+	dfx := 1
+	dfy := -2 * radius
+	xx := 0
+	yy := radius
+
+	img.Set(x, y+radius, color)
+	img.Set(x, y-radius, color)
+	img.drawHorizLine(color, x-radius, x+radius, y)
+
+	for xx < yy {
+		if f >= 0 {
+			yy--
+			dfy += 2
+			f += dfy
+		}
+		xx++
+		dfx += 2
+		f += dfx
+		img.drawHorizLine(color, x-xx, x+xx, y+yy)
+		img.drawHorizLine(color, x-xx, x+xx, y-yy)
+		img.drawHorizLine(color, x-yy, x+yy, y+xx)
+		img.drawHorizLine(color, x-yy, x+yy, y-xx)
+	}
+}
+
+
+func min3(x, y, z uint8) (o uint8) {
+	o = x
+	if y < o {
+		o = y
+	}
+	if z < o {
+		o = z
+	}
 	return
 }
 
+func max3(x, y, z uint8) (o uint8) {
+	o = x
+	if y > o {
+		o = y
+	}
+	if z > o {
+		o = z
+	}
+	return
+}
+
+func setRandomBrightness(c *image.NRGBAColor, max uint8) {
+	minc := min3(c.R, c.G, c.B)
+	maxc := max3(c.R, c.G, c.B)
+	if maxc > max {
+		return
+	}
+	n := rand.Intn(int(max-maxc)) - int(minc)
+	c.R = uint8(int(c.R) + n)
+	c.G = uint8(int(c.G) + n)
+	c.B = uint8(int(c.B) + n)
+}
+
+func rnd(from, to int) int {
+	return rand.Intn(to+1-from) + from
+}
+
+func (img *CaptchaImage) fillWithCircles(color image.NRGBAColor, n, maxradius int) {
+	maxx := img.Bounds().Max.X
+	maxy := img.Bounds().Max.Y
+	for i := 0; i < n; i++ {
+		setRandomBrightness(&color, 255)
+		r := rnd(1, maxradius)
+		img.drawCircle(color, rnd(r, maxx), rnd(r, maxy), r)
+	}
+}
+
+// func (img *CaptchaImage) strikeThrough(color image.Color) {
+// 	r := 0
+// 	maxx := img.Bounds().Max.X
+// 	maxy := img.Bounds().Max.Y
+// 	y := rnd(maxy/3, maxy-maxy/3)
+// 	for x := 0; x < maxx; x += r {
+// 		r = rnd(1, dotSize/2-1)
+// 		y += rnd(-2, 2)
+// 		if y <= 0 || y >= maxy {
+// 			y = rnd(maxy/3, maxy-maxy/3)
+// 		}
+// 		img.drawCircle(color, x, y, r)
+// 	}
+// }
+
+func (img *CaptchaImage) drawNumber(number []byte, x, y int) {
+	//skf := rand.Intn(maxSkew) - maxSkew/2
+	//if skf < 0 {
+	//	x -= skf * numberHeight
+	//}
+	d := img.numberWidth / fontWidth // number height is ignored
+	println(img.numberWidth)
+	srad := d/2             // standard (minumum) radius
+	mrad := d //srad + srad/2 // maximum radius
+	// x += srad
+	// y += srad
+	for yy := 0; yy < fontHeight; yy++ {
+		for xx := 0; xx < fontWidth; xx++ {
+			if number[yy*fontWidth+xx] != 1 {
+				continue
+			}
+			// introduce random variations
+			or := srad            //rnd(srad, mrad)
+			ox := x + (xx * mrad) //+ rnd(0, or/2)
+			oy := y + (yy * mrad) //+ rnd(0, or/2)
+			img.drawCircle(img.primaryColor, ox, oy, or)
+		}
+		//x += skf
+	}
+}