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Open-IM-Server/pkg/utils/image.go

56 lines
1.0 KiB

package utils
import (
"errors"
"image"
"image/gif"
"image/jpeg"
"image/png"
"io"
"os"
"github.com/nfnt/resize"
"golang.org/x/image/bmp"
)
func GenSmallImage(src, dst string) error {
fIn, _ := os.Open(src)
defer fIn.Close()
fOut, _ := os.Create(dst)
defer fOut.Close()
if err := scale(fIn, fOut, 0, 0, 0); err != nil {
return err
}
return nil
}
func scale(in io.Reader, out io.Writer, width, height, quality int) error {
origin, fm, err := image.Decode(in)
if err != nil {
return err
}
if width == 0 || height == 0 {
width = origin.Bounds().Max.X / 2
height = origin.Bounds().Max.Y / 2
}
if quality == 0 {
quality = 25
}
canvas := resize.Thumbnail(uint(width), uint(height), origin, resize.Lanczos3)
switch fm {
case "jpeg":
return jpeg.Encode(out, canvas, &jpeg.Options{quality})
case "png":
return png.Encode(out, canvas)
case "gif":
return gif.Encode(out, canvas, &gif.Options{})
case "bmp":
return bmp.Encode(out, canvas)
default:
return errors.New("ERROR FORMAT")
}
}