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package base64Captcha
import (
"fmt"
"image/color"
"math/rand"
"strings"
"github.com/golang/freetype/truetype"
)
//DriverMath captcha config for captcha math
type DriverMath struct {
//Height png height in pixel.
Height int
// Width Captcha png width in pixel.
Width int
//NoiseCount text noise count.
NoiseCount int
//ShowLineOptions := OptionShowHollowLine | OptionShowSlimeLine | OptionShowSineLine .
ShowLineOptions int
//BgColor captcha image background color (optional)
BgColor *color.RGBA
//fontsStorage font storage (optional)
fontsStorage FontsStorage
//Fonts loads by name see fonts.go's comment
Fonts []string
fontsArray []*truetype.Font
}
//NewDriverMath creates a driver of math
func NewDriverMath(height int, width int, noiseCount int, showLineOptions int, bgColor *color.RGBA, fontsStorage FontsStorage, fonts []string) *DriverMath {
if fontsStorage == nil {
fontsStorage = DefaultEmbeddedFonts
}
tfs := []*truetype.Font{}
for _, fff := range fonts {
tf := fontsStorage.LoadFontByName("fonts/" + fff)
tfs = append(tfs, tf)
}
if len(tfs) == 0 {
tfs = fontsAll
}
return &DriverMath{Height: height, Width: width, NoiseCount: noiseCount, ShowLineOptions: showLineOptions, fontsArray: tfs, BgColor: bgColor, Fonts: fonts}
}
//ConvertFonts loads fonts from names
func (d *DriverMath) ConvertFonts() *DriverMath {
if d.fontsStorage == nil {
d.fontsStorage = DefaultEmbeddedFonts
}
tfs := []*truetype.Font{}
for _, fff := range d.Fonts {
tf := d.fontsStorage.LoadFontByName("fonts/" + fff)
tfs = append(tfs, tf)
}
if len(tfs) == 0 {
tfs = fontsAll
}
d.fontsArray = tfs
return d
}
//GenerateIdQuestionAnswer creates id,captcha content and answer
func (d *DriverMath) GenerateIdQuestionAnswer() (id, question, answer string) {
id = RandomId()
operators := []string{"+", "-", "x"}
var mathResult int32
switch operators[rand.Int31n(3)] {
case "+":
a := rand.Int31n(20)
b := rand.Int31n(20)
question = fmt.Sprintf("%d+%d=?", a, b)
mathResult = a + b
case "x":
a := rand.Int31n(10)
b := rand.Int31n(10)
question = fmt.Sprintf("%dx%d=?", a, b)
mathResult = a * b
default:
a := rand.Int31n(80) + rand.Int31n(20)
b := rand.Int31n(80)
question = fmt.Sprintf("%d-%d=?", a, b)
mathResult = a - b
}
answer = fmt.Sprintf("%d", mathResult)
return
}
//DrawCaptcha creates math captcha item
func (d *DriverMath) DrawCaptcha(question string) (item Item, err error) {
var bgc color.RGBA
if d.BgColor != nil {
bgc = *d.BgColor
} else {
bgc = RandLightColor()
}
itemChar := NewItemChar(d.Width, d.Height, bgc)
//波浪线 比较丑
if d.ShowLineOptions&OptionShowHollowLine == OptionShowHollowLine {
itemChar.drawHollowLine()
}
//背景有文字干扰
if d.NoiseCount > 0 {
noise := RandText(d.NoiseCount, strings.Repeat(TxtNumbers, d.NoiseCount))
err = itemChar.drawNoise(noise, fontsAll)
if err != nil {
return
}
}
//画 细直线 (n 条)
if d.ShowLineOptions&OptionShowSlimeLine == OptionShowSlimeLine {
itemChar.drawSlimLine(3)
}
//画 多个小波浪线
if d.ShowLineOptions&OptionShowSineLine == OptionShowSineLine {
itemChar.drawSineLine()
}
//draw question
err = itemChar.drawText(question, d.fontsArray)
if err != nil {
return
}
return itemChar, nil
}