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crop.go
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crop.go
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package main
import (
"fmt"
"image"
"image/gif"
"image/jpeg"
"image/png"
"os"
"path/filepath"
)
func cropSave(img image.Image, outFile string, p1, p2 [2]int) (err error) {
cimg := img.(SubImager).SubImage(image.Rect(p1[0], p1[1], p2[0], p2[1]))
var fso *os.File
// 出力先ファイルの書き込みオープン
fso, err = os.Create(filepath.Clean(outFile))
if err != nil {
return
}
defer func() {
e := fso.Close()
if err == nil {
err = e
}
}()
ext, _ := getExt(outFile)
switch ext { // 出力画像の拡張子によってエンコードを変える
case "jpg", "jpeg":
err = jpeg.Encode(fso, cimg, &jpeg.Options{Quality: 100})
case "png":
err = png.Encode(fso, cimg)
case "gif":
err = gif.Encode(fso, cimg, nil)
default:
err = fmt.Errorf("unknown extension: %s", ext)
}
return
}
// 受付可能な画像の拡張子
var acceptableExts = []string{
"jpg",
"jpeg",
"png",
"gif",
}
func getExt(filePath string) (ext string, ok bool) {
ext = filepath.Ext(filePath)[1:]
for _, accebtableExt := range acceptableExts {
if ext == accebtableExt {
ok = true
break
}
}
return
}