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webp.go
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webp.go
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package coder
import (
"bufio"
"github.com/mocukie/webp-go/webp"
"github.com/mocukie/webpdeep/pkg/imagex"
"github.com/pkg/errors"
"io"
"strings"
)
var webpDecodeOpts = webp.NewDecOptions()
func init() {
webpDecodeOpts.ImageType = webp.TypeNRGBA
}
type WebP struct {
Opts *webp.EncodeOptions
CopyMeta bool
CheckImage bool
}
func (wp *WebP) Convert(in io.Reader, out io.Writer) (err error, warnings []error) {
opts := wp.Opts
img, _, meta, e := imagex.Decode(bufio.NewReader(in))
if e != nil {
err = errors.Wrap(e, "[WebP] decode image failed")
return
}
var webpData []byte
if webpData, err = webp.EncodeSlice(img, opts); err != nil {
err = errors.Wrap(err, "[WebP] encode failed")
return
}
if opts.Lossless && wp.CheckImage {
webpImg, e := webp.DecodeSlice(webpData, webpDecodeOpts)
if e != nil {
warnings = append(warnings, errors.Wrap(e, "[WebP] decode failed when compare lossless image"))
} else if !imagex.IsImageEqual(img, webpImg) {
warnings = append(warnings, errors.New("[WebP] lossless options on, but image not equal"))
}
}
if wp.CopyMeta && !meta.Empty() {
for _, cc := range [...]webp.FourCC{webp.ICCP, webp.EXIF, webp.XMP} {
if chunk := meta.Get(strings.TrimRight(string(cc[:4:4]), " ")); chunk != nil {
var tmp []byte
tmp, e = webp.SetMetadata(webpData, cc, chunk)
if e != nil {
warnings = append(warnings, errors.Wrapf(e, "[WebP] set %s failed", cc))
} else {
webpData = tmp
}
}
}
}
if _, err = out.Write(webpData); err != nil {
err = errors.Wrap(err, "[WebP] write to output failed")
}
return
}