rename CnvImage => Image

kadai2/tanaka0325/imgconv/cmd/imgconv/main.go

@@ -41,8 +41,8 @@ func main() {
 	for _, path := range paths {
 		param := imgconv.ConvertParam{
 			Path:        path,
-			BeforeImage: imgconv.NewCnvImage(*options.From),
-			AfterImage:  imgconv.NewCnvImage(*options.To),
+			BeforeImage: imgconv.NewImage(*options.From),
+			AfterImage:  imgconv.NewImage(*options.To),
 			FromExt:     *options.From,
 			ToExt:       *options.To,
 		}

kadai2/tanaka0325/imgconv/image.go

@@ -0,0 +1,81 @@
+package imgconv
+
+import (
+	"image"
+	"image/gif"
+	"image/jpeg"
+	"image/png"
+	"io"
+
+	"golang.org/x/image/bmp"
+	"golang.org/x/image/tiff"
+)
+
+type Decoder interface {
+	Decode(io.Reader) (image.Image, error)
+}
+
+type Encoder interface {
+	Encode(io.Writer, image.Image) error
+}
+
+type DecodeEncoder interface {
+	Decoder
+	Encoder
+}
+
+type Image struct{}
+
+// ImagePng is type for png format.
+type ImagePNG Image
+
+func (ip ImagePNG) Decode(r io.Reader) (image.Image, error) { return png.Decode(r) }
+
+func (ip ImagePNG) Encode(w io.Writer, i image.Image) error { return png.Encode(w, i) }
+
+// ImageJPEG is type for jpeg format.
+type ImageJPEG Image
+
+func (ip ImageJPEG) Decode(r io.Reader) (image.Image, error) { return jpeg.Decode(r) }
+
+func (ip ImageJPEG) Encode(w io.Writer, i image.Image) error { return jpeg.Encode(w, i, nil) }
+
+// ImageGIF is type for gif format.
+type ImageGIF Image
+
+func (ip ImageGIF) Decode(r io.Reader) (image.Image, error) { return gif.Decode(r) }
+
+func (ip ImageGIF) Encode(w io.Writer, i image.Image) error {
+	return gif.Encode(w, i, &gif.Options{NumColors: 256})
+}
+
+// ImageBMP is type for bmp format.
+type ImageBMP Image
+
+func (ip ImageBMP) Decode(r io.Reader) (image.Image, error) { return bmp.Decode(r) }
+
+func (ip ImageBMP) Encode(w io.Writer, i image.Image) error { return bmp.Encode(w, i) }
+
+// ImageTIFF is type for tiff format.
+type ImageTIFF Image
+
+func (ip ImageTIFF) Decode(r io.Reader) (image.Image, error) { return tiff.Decode(r) }
+
+func (ip ImageTIFF) Encode(w io.Writer, i image.Image) error { return tiff.Encode(w, i, nil) }
+
+func NewImage(ext string) DecodeEncoder {
+	switch ext {
+	case "png":
+		return &ImagePNG{}
+	case "jpg", "jpeg":
+		return &ImageJPEG{}
+	case "gif":
+		return &ImageGIF{}
+	case "bmp":
+		return &ImageBMP{}
+	case "tiff", "tif":
+		return &ImageTIFF{}
+	}
+
+	return nil
+}