Golangを使用して複数の写真をアニメーションGIF画像に変換する方法

go get -u github.com/chai2010/webp
go get -u github.com/disintegration/imaging

package main

import (
    "image"
    "image/gif"
    "os"
    "path/filepath"

    "github.com/chai2010/webp"
    "github.com/disintegration/imaging"
)

func loadImages(dir string) ([]image.Image, error) {
    var images []image.Image

    err := filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
        // Check if the file is an image file
        if isImage(path) {
            // Decode the image file
            img, err := loadImage(path)
            if err != nil {
                return err
            }

            images = append(images, img)
        }

        return nil
    })

    if err != nil {
        return nil, err
    }

    return images, nil
}

func isImage(path string) bool {
    ext := filepath.Ext(path)
    switch ext {
    case ".jpg", ".jpeg", ".png", ".webp":
        return true
    default:
        return false
    }
}

func loadImage(path string) (image.Image, error) {
    file, err := os.Open(path)
    if err != nil {
        return nil, err
    }
    defer file.Close()

    ext := filepath.Ext(path)
    switch ext {
    case ".jpg", ".jpeg":
        return imaging.Decode(file)
    case ".png":
        return webp.Decode(file)
    case ".webp":
        return png.Decode(file)
    default:
        return nil, fmt.Errorf("unsupported image format")
    }
}

func convertToGIF(dir string, output string) error {
    // Load all images in the directory
    images, err := loadImages(dir)
    if err != nil {
        return err
    }

    // Create a new GIF image
    anim := gif.GIF{}

    // Add each image to the GIF
    for _, img := range images {
        // Convert the image to RGBA format
        rgba := imaging.New(img.Bounds().Max.X, img.Bounds().Max.Y, color.NRGBA{0, 0, 0, 0})
        draw.Draw(rgba, rgba.Bounds(), img, image.ZP, draw.Src)

        // Add the image to the GIF animation
        anim.Image = append(anim.Image, rgba)
        anim.Delay = append(anim.Delay, 10) // Delay between frames (in 10ms units)
    }

    // Save the GIF animation to the output file
    file, err := os.Create(output)
    if err != nil {
        return err
    }
    defer file.Close()

    return gif.EncodeAll(file, &anim)
}

func main() {
    dir := "./images"   // Directory containing the images
    output := "output.gif" // Output GIF file

    err := convertToGIF(dir, output)
    if err != nil {
        fmt.Printf("Failed to convert images to GIF: %v
", err)
    } else {
        fmt.Println("Images successfully converted to GIF")
    }
}