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解答：1.引入两个包，log,net/http2.安装godoc,apt install golang-golang-x-tools,查找某个函数用法godoc strconv 3.函数有多个返回值时，multiple-value strconv.Atoi() in single-value context ，不需要的参数要用_接收4.Lissajour服务里面的cycles参数要是float64类型，使用cycles,_ := strconv.ParseFloat(v[0],64)函数转换5.不能有任何输出语句，否则会弹出下载框6.传参不能太大，要进行一下判断，否则CPU占满
import (
"fmt"
"image"
"image/color"
"image/gif"
"math"
"math/rand"
"log"
"net/http"
"strconv"
)
//定义一个slice切片变量,复合声明
var palette = []color.Color{color.White,color.RGBA{0,255,68,255},color.RGBA{26,255}}
//声明一组常量
const (
whiteIndex = 0
blackIndex = 1
)
func main() {
http.HandleFunc("/",handler)
log.Fatal(http.ListenAndServe("0.0.0.0:8000",nil))
fmt.Println("hello")
}
//处理http请求
func handler(w http.ResponseWriter,r *http.Request) {
//if语句中嵌套表达式
if err := r.ParseForm(); err != nil {
log.Print(err)
}
for k,v := range r.Form {
if k == "cycles" {
//函数有多个返回值时，multiple-value strconv.Atoi() in single-value context ，不需要的参数要用_接收
cycles,64)
//fmt.Fprintf(w,"%q:%d",k,cycles);
//调用gif图形函数
if cycles < 50 {
lissajous(w,cycles)
}
} else {
fmt.Fprintf(w,"URL PATH:%q
",r.URL.Path)
fmt.Fprintf(w,"%q:%q",v)
}
}
}
//gif图形函数
func lissajous(out http.ResponseWriter,cycles float64) {
const (
//cycles = 5 // number of complete x oscillator revolutions
res = 0.001 // angular resolution
size = 100 // image canvas covers [-size..+size]
nframes = 64 // number of animation frames
delay = 8 // delay between frames in 10ms units
)
freq := rand.Float64() * 3.0 // relative frequency of y oscillator
anim := gif.GIF{LoopCount: nframes}
phase := 0.0 // phase difference
for i := 0; i < nframes; i++ {
rect := image.Rect(0,2*size+1,2*size+1)
img := image.NewPaletted(rect,palette)
for t := 0.0; t < cycles*2*math.Pi; t += res {
x := math.Sin(t)
y := math.Sin(t*freq + phase)
img.SetColorIndex(size+int(x*size+0.5),size+int(y*size+0.5),blackIndex)
}
phase += 0.1
anim.Delay = append(anim.Delay,delay)
anim.Image = append(anim.Image,img)
}
gif.EncodeAll(out,&anim) // NOTE: ignoring encoding errors
}
