compy/transcoder/png.go

36 lines
675 B
Go

package transcoder
import (
"github.com/barnacs/compy/proxy"
"github.com/chai2010/webp"
"image/png"
"net/http"
)
type Png struct{}
func (t *Png) Transcode(w *proxy.ResponseWriter, r *proxy.ResponseReader, headers http.Header) error {
img, err := png.Decode(r)
if err != nil {
return err
}
if SupportsWebP(headers) {
w.Header().Set("Content-Type", "image/webp")
options := webp.Options{
Lossless: false,
}
if err = webp.Encode(w, img, &options); err != nil {
return err
}
} else {
enc := &png.Encoder{
CompressionLevel: png.BestCompression,
}
if err = enc.Encode(w, img); err != nil {
return err
}
}
return nil
}