golang 遍历并批量压缩图片

100

101

package main
 
import (
    "bytes"
    "fmt"
    "image"
    "io/ioutil"
    "mylog"
    "os"
    "path"
    "github.com/nfnt/resize"
    _ "image/gif"
    "image/jpeg"
    _ "image/png"
)
 
func main() {
 
    //  GetFiles(".")
    pathslist := GetFiles2(".")
 
    mapRule := make(map[string]int)
    mapRule[".jpg"] = 1
    mapRule[".png"] = 1
    mapRule[".jpeg"] = 1
    for i, m := range pathslist {
        mylog.Println(i, "===>", m)
        ext := path.Ext(m)
        //  fmt.Println(ext)
        if mapRule[ext] == 1 {
            fmt.Println(m)
            old, err := os.ReadFile(m)
            if err != nil {
                fmt.Println(err)
            }
            new_pic := CompressImageResource(old)
 
            ioutil.WriteFile(m, new_pic, 0666)
        }
    }
 
}
 
// 默认最大高度
const MaxHeight uint = 1080
 
// 文件小于 200KB 或者不是jpeg/png格式，不再压缩
func CompressImageResource(data []byte) []byte {
    if len(data) < 1024*200 {
        return data
    }
 
    img, _, err := image.Decode(bytes.NewReader(data))
    if err != nil {
        mylog.Printf("jpeg png compress failed,err:%v", err)
        return data
    }
    // 修改图片的大小
    m := resize.Resize(0, MaxHeight, img, resize.Lanczos3)
    buf := bytes.Buffer{}
 
    // 修改图片的质量
    err = jpeg.Encode(&buf, m, &jpeg.Options{Quality: 85})
    if err != nil {
        mylog.Printf("jpeg compress failed,err:%v", err)
        return data
    }
    if buf.Len() > len(data) {
        return data
    }
    return buf.Bytes()
}
 
func GetFiles(folder string) {
    files, _ := ioutil.ReadDir(folder)
    for _, file := range files {
        if file.IsDir() {
            GetFiles(folder + "/" + file.Name())
        } else {
            fmt.Println(folder + "/" + file.Name() + ",扩展名:" + path.Ext(file.Name()))
        }
    }
 
}
 
func GetFiles2(folder string) []string {
    res := []string{}
    files, _ := ioutil.ReadDir(folder)
    for _, file := range files {
        if file.IsDir() {
            temp2 := GetFiles2(folder + "/" + file.Name())
            res = append(res, temp2...)
        } else {
            res = append(res, folder+"/"+file.Name())
            //  fmt.Println(folder + "/" + file.Name() + ",扩展名:" + path.Ext(file.Name()))
 
        }
    }
 
    return res
}

效果：遍历当前根目录，批量压缩图片

mylog是自定义的日志包

在压缩那步增加并发代码跑，可以大幅提高效率。

并发:

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

package main
 
import (
    "errors"
    "fmt"
    "image"
    "io/ioutil"
    "mylog"
    "os"
    "path"
    "strings"
    "sync"
    "time"
 
    "image/gif"
    "image/jpeg"
    "image/png"
 
    "github.com/nfnt/resize"
    _ "golang.org/x/image/bmp"
)
 
type Glimit struct {
    n int
    c chan struct{}
}
 
// initialization Glimit struct
func New(n int) *Glimit {
    return &Glimit{
        n: n,
        c: make(chan struct{}, n),
    }
}
 
// Run f in a new goroutine but with limit.
func (g *Glimit) Run(f func()) {
    g.c <- struct{}{}
    go func() {
        f()
        <-g.c
    }()
}
 
var wg = sync.WaitGroup{}
var mu sync.Mutex
var count int
 
func main() {
 
    since := time.Now()
    pathslist := GetFiles2(".")
 
    mapRule := make(map[string]int)
    mapRule[".jpg"] = 1
    mapRule[".png"] = 1
    mapRule[".jpeg"] = 1
    mapRule[".gif"] = 1
    mapRule[".bmp"] = 1
 
    g := New(20)
    for i, m := range pathslist {
 
        ext := strings.ToLower(path.Ext(m))
        that_m := m //并发时 很重要
        //  fmt.Println(ext)
        if mapRule[ext] == 1 {
            mylog.Println(i, "===>", m)
            wg.Add(1)
            fmt.Println(m)
            goFunc := func() {
                compressImage_with_path(that_m, that_m)
                mu.Lock()
                count++
                mu.Unlock()
                wg.Done()
            }
            g.Run(goFunc)
 
        }
    }
    wg.Wait()
    fmt.Println(time.Since(since), "，执行次数：", count)
    time.Sleep(10 * time.Second)
}
 
//压缩图片
func compressImage_with_path(imagePath, savePath string) error {
    mylog.Println("文件路径是:", imagePath)
    file, _ := os.Open(imagePath)
    defer file.Close()
    w := 500
    h := 0
 
    img, layout, err := image.Decode(file)
    if err != nil {
        mylog.Println("解码错误:<<<", imagePath, ">>>==>", err)
        return err
    } else {
        mylog.Println("格式:", imagePath, "==>", layout)
    }
    fmt.Println(img.Bounds().Dx())
 
    if w >= img.Bounds().Dx() && w >= img.Bounds().Dy() {
        return nil
    }
    if img.Bounds().Dx() < img.Bounds().Dy() { //考虑翻转的图片
        w, h = h, w
    }
 
    // 调用resize库进行图片缩放
    m := resize.Resize(uint(w), uint(h), img, resize.Lanczos3)
 
    // 需要保存的文件
    imgfile, _ := os.Create(savePath)
    defer imgfile.Close()
    switch layout {
    case "png":
        err = png.Encode(imgfile, m)
    case "jpeg", "jpg", "bmp":
        err = jpeg.Encode(imgfile, m, &jpeg.Options{Quality: 85})
    case "gif":
        err = gif.Encode(imgfile, m, &gif.Options{NumColors: 32})
    default:
        return errors.New("该图片格式不支持压缩")
    }
 
    if err != nil {
        return err
    }
 
    return nil
}
func GetFiles2(folder string) []string {
    res := []string{}
    files, _ := ioutil.ReadDir(folder)
    for _, file := range files {
        if file.IsDir() {
            temp2 := GetFiles2(folder + "/" + file.Name())
            res = append(res, temp2...)
        } else {
            res = append(res, folder+"/"+file.Name())
            //  fmt.Println(folder + "/" + file.Name() + ",扩展名:" + path.Ext(file.Name()))
 
        }
    }
 
    return res
}