compy/transcoder/jpeg.go
Andrew Gaul 9518dc2f1a Add PNG and JPEG to WebP transcoding
WebP lossy mode offers up to 30% better compression than JPEG.
2017-01-16 00:06:17 -08:00

46 lines
897 B
Go

package transcoder
import (
"github.com/barnacs/compy/proxy"
"github.com/chai2010/webp"
"github.com/pixiv/go-libjpeg/jpeg"
"net/http"
)
type Jpeg struct {
decOptions *jpeg.DecoderOptions
encOptions *jpeg.EncoderOptions
}
func NewJpeg(quality int) *Jpeg {
return &Jpeg{
decOptions: &jpeg.DecoderOptions{},
encOptions: &jpeg.EncoderOptions{
Quality: quality,
OptimizeCoding: true,
},
}
}
func (t *Jpeg) Transcode(w *proxy.ResponseWriter, r *proxy.ResponseReader, headers http.Header) error {
img, err := jpeg.Decode(r, t.decOptions)
if err != nil {
return err
}
if SupportsWebP(headers) {
options := webp.Options{
Lossless: false,
Quality: float32(t.encOptions.Quality),
}
if err = webp.Encode(w, img, &options); err != nil {
return err
}
} else {
if err = jpeg.Encode(w, img, t.encOptions); err != nil {
return err
}
}
return nil
}