接下来是一个用github.com/afocus/captcha库生成验证码的示例

go
package main

import (
	"image/color"
	"image/png"
	"net/http"

	"github.com/afocus/captcha"
)

var cap *captcha.Captcha

func main() {

	cap = captcha.New()

	if err := cap.SetFont("comic.ttf"); err != nil {
		panic(err.Error())
	}

	/*
	   //We can load font not only from localfile, but also from any []byte slice
	   	fontContenrs, err := ioutil.ReadFile("comic.ttf")
	   	if err != nil {
	   		panic(err.Error())
	   	}

	   	err = cap.AddFontFromBytes(fontContenrs)
	   	if err != nil {
	   		panic(err.Error())
	   	}
	*/

	cap.SetSize(150, 100)
	cap.SetDisturbance(captcha.HIGH)
	cap.SetFrontColor(color.RGBA{255, 255, 255, 255})
	cap.SetBkgColor(color.RGBA{255, 0, 0, 255}, color.RGBA{0, 0, 255, 255}, color.RGBA{0, 153, 0, 255})

	http.HandleFunc("/r", func(w http.ResponseWriter, r *http.Request) {
		img, str := cap.Create(6, captcha.ALL)
		png.Encode(w, img)
		println(str)
	})

	http.HandleFunc("/c", func(w http.ResponseWriter, r *http.Request) {
		str := r.URL.RawQuery
		img := cap.CreateCustom(str)
		png.Encode(w, img)
	})

	http.ListenAndServe(":8085", nil)

}

除却这些代码，还需要包含特定字体

包含字体的.ttf文件，切记，这个库大小超过150 x 150,生成的验证码会出现不可识别的情况，所以适合生成小型验证码需求