英文:
Rendering .gif in Go
问题
我正在尝试使一个代码示例正常工作。这个示例来自于《The GO Programming Language》（https://github.com/adonovan/gopl.io/blob/1ae3ec64947b7a5331b186f1b1138fc98c0f1c06/ch1/lissajous/main.go）。当尝试查看动画时，gif 图像无法渲染。gif 渲染软件报告了以下错误：
自 2016 年以来，.gif 标准是否发生了变化，或者我做错了什么？
// 版权所有 © 2016 Alan A. A. Donovan & Brian W. Kernighan.
// 许可证：https://creativecommons.org/licenses/by-nc-sa/4.0/
// Lissajous 生成随机 Lissajous 图形的 GIF 动画。
package main
import (
"image"
"image/color"
"image/gif"
"io"
"math"
"math/rand"
"os"
)
var palette = []color.Color{color.White, color.Black}
const (
whiteIndex = 0 // 调色板中的第一个颜色
blackIndex = 1 // 调色板中的下一个颜色
)
func main() {
lissajous(os.Stdout)
}
func lissajous(out io.Writer) {
const (
cycles = 5 // x 振荡器的完整周期数
res = 0.001 // 角度分辨率
size = 100 // 图像画布覆盖的范围 [-size..+size]
nframes = 64 // 动画帧数
delay = 8 // 帧之间的延迟（以 10ms 为单位）
)
freq := rand.Float64() * 3.0 // y 振荡器的相对频率
anim := gif.GIF{LoopCount: nframes}
phase := 0.0 // 相位差
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) // 注意：忽略编码错误
}
构建和运行命令如下：
go build .\main.go
.\main.exe > out.gif
英文:
I am trying to get a code example to work. It is from 'The GO Programming Language' (https://github.com/adonovan/gopl.io/blob/1ae3ec64947b7a5331b186f1b1138fc98c0f1c06/ch1/lissajous/main.go). When trying to view the animation, the gif doesn't get rendered. The gif rendering software reports the error:
Has the .gif standards changed since 2016 or is there something I'm doing wrong?
// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
// 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 build and run commands are:
go build .\main.go
.\main.exe > out.gif
答案1
得分: 1
使用 bufio.NewWriter
func main() {
fileName := "1.gif"
f, err3 := os.Create(fileName)
if err3 != nil {
fmt.Println("创建文件失败")
}
w := bufio.NewWriter(f)
lissajous(w)
w.Flush()
f.Close()
}
或者
func main() {
w := bufio.NewWriter(os.Stdout)
lissajous(w)
w.Flush()
os.Stdout.Close()
}
英文:
Use bufio.NewWriter
func main() {
fileName := "1.gif"
f, err3 := os.Create(fileName)
if err3 != nil {
fmt.Println("create file fail")
}
w := bufio.NewWriter(f)
lissajous(w)
w.Flush()
f.Close()
}
or
func main() {
w := bufio.NewWriter(os.Stdout)
lissajous(w)
w.Flush()
os.Stdout.Close()
}
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