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captcha
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Make New() concurrency-safe (#6)

This commit is contained in:
Takuya Kaneda 2020-07-19 22:25:17 +09:00 committed by GitHub
parent 26e89c7d47
commit 3db110f2af
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 23 additions and 23 deletions
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46
captcha.go
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@ -22,7 +22,6 @@ import (
const charPreset = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" const charPreset = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
var rng = rand.New(rand.NewSource(time.Now().UnixNano()))
var ttfFont *truetype.Font var ttfFont *truetype.Font
// Options manage captcha generation details. // Options manage captcha generation details.
@ -105,6 +104,7 @@ func (data *Data) WriteGIF(w io.Writer, o *gif.Options) error {
func init() { func init() {
ttfFont, _ = freetype.ParseFont(ttf) ttfFont, _ = freetype.ParseFont(ttf)
rand.Seed(time.Now().UnixNano())
} }
// LoadFont let you load an external font. // LoadFont let you load an external font.
@ -169,7 +169,7 @@ func NewMathExpr(width int, height int, option ...SetOption) (*Data, error) {
func randomText(opts *Options) (text string) { func randomText(opts *Options) (text string) {
n := len(opts.CharPreset) n := len(opts.CharPreset)
for i := 0; i < opts.TextLength; i++ { for i := 0; i < opts.TextLength; i++ {
text += string(opts.CharPreset[rng.Intn(n)]) text += string(opts.CharPreset[rand.Intn(n)])
} }
return text return text
@ -178,16 +178,16 @@ func randomText(opts *Options) (text string) {
func drawNoise(img *image.NRGBA, opts *Options) { func drawNoise(img *image.NRGBA, opts *Options) {
noiseCount := (opts.width * opts.height) / int(28.0/opts.Noise) noiseCount := (opts.width * opts.height) / int(28.0/opts.Noise)
for i := 0; i < noiseCount; i++ { for i := 0; i < noiseCount; i++ {
x := rng.Intn(opts.width) x := rand.Intn(opts.width)
y := rng.Intn(opts.height) y := rand.Intn(opts.height)
img.Set(x, y, randomColor()) img.Set(x, y, randomColor())
} }
} }
func randomColor() color.RGBA { func randomColor() color.RGBA {
red := rng.Intn(256) red := rand.Intn(256)
green := rng.Intn(256) green := rand.Intn(256)
blue := rng.Intn(256) blue := rand.Intn(256)
return color.RGBA{R: uint8(red), G: uint8(green), B: uint8(blue), A: uint8(255)} return color.RGBA{R: uint8(red), G: uint8(green), B: uint8(blue), A: uint8(255)}
} }
@ -205,14 +205,14 @@ func drawSineCurve(img *image.NRGBA, opts *Options) {
if opts.width <= 40 { if opts.width <= 40 {
xStart, xEnd = 1, opts.width-1 xStart, xEnd = 1, opts.width-1
} else { } else {
xStart = rng.Intn(opts.width/10) + 1 xStart = rand.Intn(opts.width/10) + 1
xEnd = opts.width - rng.Intn(opts.width/10) - 1 xEnd = opts.width - rand.Intn(opts.width/10) - 1
} }
curveHeight := float64(rng.Intn(opts.height/6) + opts.height/6) curveHeight := float64(rand.Intn(opts.height/6) + opts.height/6)
yStart := rng.Intn(opts.height*2/3) + opts.height/6 yStart := rand.Intn(opts.height*2/3) + opts.height/6
angle := 1.0 + rng.Float64() angle := 1.0 + rand.Float64()
yFlip := 1.0 yFlip := 1.0
if rng.Intn(2) == 0 { if rand.Intn(2) == 0 {
yFlip = -1.0 yFlip = -1.0
} }
curveColor := randomColorFromOptions(opts) curveColor := randomColorFromOptions(opts)
@ -232,15 +232,15 @@ func drawText(text string, img *image.NRGBA, opts *Options) error {
ctx.SetFont(ttfFont) ctx.SetFont(ttfFont)
fontSpacing := opts.width / len(text) fontSpacing := opts.width / len(text)
fontOffset := rng.Intn(fontSpacing / 2) fontOffset := rand.Intn(fontSpacing / 2)
for idx, char := range text { for idx, char := range text {
fontScale := 0.8 + rng.Float64()*0.4 fontScale := 0.8 + rand.Float64()*0.4
fontSize := float64(opts.height) / fontScale * opts.FontScale fontSize := float64(opts.height) / fontScale * opts.FontScale
ctx.SetFontSize(fontSize) ctx.SetFontSize(fontSize)
ctx.SetSrc(image.NewUniform(randomColorFromOptions(opts))) ctx.SetSrc(image.NewUniform(randomColorFromOptions(opts)))
x := fontSpacing*idx + fontOffset x := fontSpacing*idx + fontOffset
y := opts.height/6 + rng.Intn(opts.height/3) + int(fontSize/2) y := opts.height/6 + rand.Intn(opts.height/3) + int(fontSize/2)
pt := freetype.Pt(x, y) pt := freetype.Pt(x, y)
if _, err := ctx.DrawString(string(char), pt); err != nil { if _, err := ctx.DrawString(string(char), pt); err != nil {
return err return err
@ -256,19 +256,19 @@ func randomColorFromOptions(opts *Options) color.Color {
return randomInvertColor(opts.BackgroundColor) return randomInvertColor(opts.BackgroundColor)
} }
return opts.Palette[rng.Intn(length)] return opts.Palette[rand.Intn(length)]
} }
func randomInvertColor(base color.Color) color.Color { func randomInvertColor(base color.Color) color.Color {
baseLightness := getLightness(base) baseLightness := getLightness(base)
var value float64 var value float64
if baseLightness >= 0.5 { if baseLightness >= 0.5 {
value = baseLightness - 0.3 - rng.Float64()*0.2 value = baseLightness - 0.3 - rand.Float64()*0.2
} else { } else {
value = baseLightness + 0.3 + rng.Float64()*0.2 value = baseLightness + 0.3 + rand.Float64()*0.2
} }
hue := float64(rng.Intn(361)) / 360 hue := float64(rand.Intn(361)) / 360
saturation := 0.6 + rng.Float64()*0.2 saturation := 0.6 + rand.Float64()*0.2
return hsva{h: hue, s: saturation, v: value, a: 255} return hsva{h: hue, s: saturation, v: value, a: 255}
} }
@ -311,8 +311,8 @@ func minColor(numList ...uint32) (min uint32) {
} }
func randomEquation() (text string, equation string) { func randomEquation() (text string, equation string) {
left := 1 + rng.Intn(9) left := 1 + rand.Intn(9)
right := 1 + rng.Intn(9) right := 1 + rand.Intn(9)
text = strconv.Itoa(left + right) text = strconv.Itoa(left + right)
equation = strconv.Itoa(left) + "+" + strconv.Itoa(right) equation = strconv.Itoa(left) + "+" + strconv.Itoa(right)