Go语言编写Gif生成练习，创建损坏的文件

I am working on the exercises in the book The Go Programming Language. In the first chapter, there is an exercise that generates a gif. I have run the program without errors, but have been unable to open the gif. It appears corrupt.

I am on Windows 10 and have tried to open the file in browsers, IfranView 64bit version 4.53, and the default Photos app.

Code:

// Lissajous generates GIF animations of random Lissajous figures.
package main

import (
    "image"
    "image/color"
    "image/gif"
    "io"
    "math"
    "math/rand"
    "os"
)

var palette = []color.Color{color.White, color.Black}
const (
    whiteIndex = 0 // first color in palette
    blackIndex = 1 // next color in palette
)
func main() {
    lissajous(os.Stdout)
}
func lissajous(out io.Writer) {
    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, 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
}

I run the application in Powershell by evoking go run {programname}.go > out.gif and by compiling and running ./{programname}.exe > out.gif.

How can I figure out what's wrong with the gif and how can I generate it correctly?

I'm unable to reproduce your issue.

cmd.exe
Microsoft Windows [Version 10.0.18362.239]

>go version
go version devel +89d300b821 Sun Jul 14 20:15:47 2019 +0000 windows/amd64

>go run lissajous.go > lissajous.gif

Firefox 68.0 (64-bit)
Menu -> Open File -> lissajous.gif

lissajous.go (from the question):

// Lissajous generates GIF animations of random Lissajous figures.
package main

import (
    "image"
    "image/color"
    "image/gif"
    "io"
    "math"
    "math/rand"
    "os"
)

var palette = []color.Color{color.White, color.Black}

const (
    whiteIndex = 0 // first color in palette
    blackIndex = 1 // next color in palette
)

func main() {
    lissajous(os.Stdout)
}
func lissajous(out io.Writer) {
    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, 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
}

The problem arises only if you use Powershell. I faced the same problem and solved it by executing the go run command using cmd.