+
+
package imageconverter
+
+import (
+ "fmt"
+ "image"
+ "image/gif"
+ "image/jpeg"
+ "image/png"
+ "io"
+ "os"
+ "path/filepath"
+ "strings"
+
+ "golang.org/x/image/bmp"
+ "golang.org/x/image/tiff"
+)
+
+var (
+ convImage func(path string, info os.FileInfo, err error, args Args) error
+ execute func(source, dest string) (err error)
+ osOpen func(name string) (*os.File, error)
+ osCreate func(name string) (*os.File, error)
+ sourceFileClose func(file *os.File) error
+ destFileClose func(file *os.File) error
+ imageDecode func(r io.Reader) (image.Image, string, error)
+ newImgEncoder func(ext string) (Encoder, error)
+)
+
+func init() {
+ convImage = convertImage
+ execute = exec
+ osOpen = os.Open
+ sourceFileClose = func(file *os.File) error {
+ return file.Close()
+ }
+ osCreate = os.Create
+ destFileClose = func(file *os.File) error {
+ return file.Close()
+ }
+ imageDecode = image.Decode
+ newImgEncoder = newImageEncoder
+
+}
+
+type Args struct {
+ Directory string
+ BeforeExtension string
+ AfterExtension string
+}
+
+type Encoder interface {
+ Encode(w io.Writer, m image.Image) error
+}
+
+type JpegEncoder struct{}
+
+func (enc JpegEncoder) Encode(w io.Writer, m image.Image) error {
+ return jpeg.Encode(w, m, &jpeg.Options{Quality: jpeg.DefaultQuality})
+}
+
+type PngEncoder struct{}
+
+func (enc PngEncoder) Encode(w io.Writer, m image.Image) error {
+ return png.Encode(w, m)
+}
+
+type GifEncoder struct{}
+
+func (enc GifEncoder) Encode(w io.Writer, m image.Image) error {
+ return gif.Encode(w, m, &gif.Options{NumColors: 256})
+}
+
+type BmpEncoder struct{}
+
+func (enc BmpEncoder) Encode(w io.Writer, m image.Image) error {
+ return bmp.Encode(w, m)
+}
+
+type TiffEncoder struct{}
+
+func (enc TiffEncoder) Encode(w io.Writer, m image.Image) error {
+ return tiff.Encode(w, m, nil)
+}
+
+func newImageEncoder(dest string) (Encoder, error) {
+ switch strings.ToLower(filepath.Ext(dest)) {
+ case ".jpg", ".jpeg":
+ return JpegEncoder{}, nil
+ case ".png":
+ return PngEncoder{}, nil
+ case ".gif":
+ return GifEncoder{}, nil
+ case ".bmp":
+ return BmpEncoder{}, nil
+ case ".tiff", ".tif":
+ return TiffEncoder{}, nil
+ default:
+ return nil, fmt.Errorf("image file could not be created due to an unknown extension. target: %s", dest)
+ }
+}
+
+func exec(source, dest string) (err error) {
+ sourceFile, err := osOpen(source)
+ if err != nil {
+ return fmt.Errorf("file could not be opened. target: %s", source)
+ }
+ defer sourceFileClose(sourceFile)
+
+ destFile, err := osCreate(dest)
+ if err != nil {
+ return fmt.Errorf("image file could not be created. target: %s", dest)
+ }
+
+ defer func() {
+ if err == nil {
+ err = destFileClose(destFile)
+ }
+ }()
+
+ img, _, err := imageDecode(sourceFile)
+ if err != nil {
+ return err
+ }
+
+ e, err := newImgEncoder(dest)
+ if err != nil {
+ return err
+ }
+ return e.Encode(destFile, img)
+}
+
+func convertImage(path string, info os.FileInfo, err error, args Args) error {
+ if err != nil {
+ return fmt.Errorf("prevent panic by handling failure accessing a path %q: %v\n", path, err)
+ }
+
+ if info.IsDir() {
+ return nil
+ }
+
+ ext := strings.ToLower(filepath.Ext(path))
+ if "."+args.BeforeExtension != ext {
+ return nil
+ }
+ return execute(path, replaceExt(info.Name(), "."+args.AfterExtension))
+}
+
+// 指定したディレクトリ以下のJPGファイルをPNGに変換（デフォルト）
+// ディレクトリ以下は再帰的に処理する
+// 変換前と変換後の画像形式を指定できる（オプション）
+func Convert(args Args) error {
+ return filepath.Walk(args.Directory, func(path string, info os.FileInfo, err error) error {
+ return convImage(path, info, err, args)
+ })
+}
+
+func replaceExt(filePath, toExt string) string {
+ return filePath[:len(filePath)-len(filepath.Ext(filePath))] + toExt
+}
+
+
+
+
+
package main
+
+import (
+ "flag"
+ "fmt"
+ "os"
+ "testing"
+
+ "github.com/gopherdojo/dojo8/kadai1/wataboru/imageconverter"
+)
+
+const (
+ // ExitCodeSuccess is the exit code on success
+ ExitCodeSuccess = 0
+ // ExitCodeError is the exit code when failed
+ ExitCodeError = 1
+ // ExitCodeError is the exit code when failed
+ ExitCodeInvalidDirectoryError = 2
+)
+
+var (
+ args imageconverter.Args
+ osStat func(name string) (os.FileInfo, error)
+ osIsNotExist func(err error) bool
+ imgconv func(args imageconverter.Args) error
+)
+
+func init() {
+ testing.Init()
+ flag.StringVar(&args.Directory, "dir", "", "Input target Directory.\n ex) `--dir=./convert_image`")
+ flag.StringVar(&args.Directory, "d", "", "Input target Directory. (short)")
+ flag.StringVar(&args.BeforeExtension, "before", "jpg", "Input extension before conversion.\n ex) `--before=png`")
+ flag.StringVar(&args.BeforeExtension, "b", "jpg", "Input extension before conversion. (short)")
+ flag.StringVar(&args.AfterExtension, "after", "png", "Input extension after conversion.\n ex) `--after=jpg`")
+ flag.StringVar(&args.AfterExtension, "a", "png", "Input extension after conversion. (short)")
+ flag.Parse()
+
+ osStat = func(name string) (os.FileInfo, error) {
+ return os.Stat(name)
+ }
+ osIsNotExist = func(err error) bool {
+ return os.IsNotExist(err)
+ }
+ imgconv = imageconverter.Convert
+
+}
+
+func run() int {
+ if args.Directory == "" {
+ fmt.Fprintln(os.Stderr, "Input target Directory.\n ex) `--dir=./convert_image`")
+ return ExitCodeInvalidDirectoryError
+ }
+
+ if _, err := osStat(args.Directory); osIsNotExist(err) {
+ fmt.Fprintln(os.Stderr, "Target directory is not found.")
+ return ExitCodeInvalidDirectoryError
+ }
+
+ if err := imgconv(args); err != nil {
+ fmt.Fprintln(os.Stderr, err.Error())
+ return ExitCodeError
+ }
+
+ return ExitCodeSuccess
+}
+
+func main() {
+ os.Exit(run())
+}
+
+
+