GO language to achieve bulk compression of images and watermarks

Some time ago, when I wanted to make a photo station, I took a lot of photos with my mobile phone. However, it was too troublesome to use PS to compress and modify the size. Finally, I came up with the idea of using golang to realize it. github.com /nfnt/resize, a third library, only supports the JPG image format.

package main

import (

    "fmt"

    "github.com/nfnt/resize"

    "image"

    "image/draw"

    "image/jpeg"

    "image/png"

    "io/ioutil"

    "log"

    "math/rand"

    "os"

    "runtime"

    "strconv"

    "strings"

    "time"

)

func main() {

    runtime.GOMAXPROCS(runtime.NumCPU())

    cmd("data/")

    fmt.Println("OK!")

}

//  Perform operations 

func cmd(path string) {

    files, _ := ioutil.ReadDir(path)

    for _, file := range files {

        if file.IsDir() {

            fmt.Println(" directory " + file.Name())

            cmd(path + file.Name() + "/")

        } else {

            if strings.Contains(strings.ToLower(file.Name()), ".jpg") {

                //  Random name 

                to := path + random_name() + ".jpg"

                origin := path + file.Name()

                fmt.Println(" Are dealing with " + origin + ">>>" + to)

                cmd_resize(origin, 2048, 0, to)

                defer os.Remove(origin)

            }

        }

    }

}

//  Change the size 

func cmd_resize(file string, width uint, height uint, to string) {

    //  Open the image and decode it 

    file_origin, _ := os.Open(file)

    origin, _ := jpeg.Decode(file_origin)

    defer file_origin.Close()

    canvas := resize.Resize(width, height, origin, resize.Lanczos3)

    file_out, err := os.Create(to)

    if err != nil {

        log.Fatal(err)

    }

    defer file_out.Close()

    jpeg.Encode(file_out, canvas, &jpeg.Options{80})

    // cmd_watermark(to, strings.Replace(to, ".jpg", "@big.jpg", 1))

    cmd_thumbnail(to, 480, 360, strings.Replace(to, ".jpg", "@small.jpg", 1))

}

func cmd_thumbnail(file string, width uint, height uint, to string) {

    //  Open the image and decode it 

    file_origin, _ := os.Open(file)

    origin, _ := jpeg.Decode(file_origin)

    defer file_origin.Close()

    canvas := resize.Thumbnail(width, height, origin, resize.Lanczos3)

    file_out, err := os.Create(to)

    if err != nil {

        log.Fatal(err)

    }

    defer file_out.Close()

    jpeg.Encode(file_out, canvas, &jpeg.Options{80})

}

//  The watermark 

func cmd_watermark(file string, to string) {

    //  Open the image and decode it 

    file_origin, _ := os.Open(file)

    origin, _ := jpeg.Decode(file_origin)

    defer file_origin.Close()

    //  Open the watermark and decode it 

    file_watermark, _ := os.Open("watermark.png")

    watermark, _ := png.Decode(file_watermark)

    defer file_watermark.Close()

    // Original map boundary 

    origin_size := origin.Bounds()

    // Create a new layer 

    canvas := image.NewNRGBA(origin_size)

    //  Stick the original figure 

    draw.Draw(canvas, origin_size, origin, image.ZP, draw.Src)

    //  Post watermark pictures 

    draw.Draw(canvas, watermark.Bounds().Add(image.Pt(30, 30)), watermark, image.ZP, draw.Over)

    // Generate a new image 

    create_image, _ := os.Create(to)

    jpeg.Encode(create_image, canvas, &jpeg.Options{95})

    defer create_image.Close()

}

//  Randomly generated file name 

func random_name() string {

    rand.Seed(time.Now().UnixNano())

    return strconv.Itoa(rand.Int())

}

That's all for this article. I hope it will be helpful for you to master go.