thumbnail/DirectThumbnailer.go

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package thumbnail
import (
"image"
"mime"
"path/filepath"
"strings"
)
type DirectThumbnailer struct {
cfg Config
}
var _ Thumbnailer = &DirectThumbnailer{} // interface assertion
func NewThumbnailer(w, h int) Thumbnailer {
opts := DefaultConfig
opts.Width = w
opts.Height = h
return NewThumbnailerEx(&opts)
}
func NewThumbnailerEx(opts *Config) Thumbnailer {
if opts == nil {
opts = &DefaultConfig
}
return &DirectThumbnailer{cfg: *opts}
}
func (this *DirectThumbnailer) RenderFile(absPath string) ([]byte, error) {
mimeType := mime.TypeByExtension(filepath.Ext(absPath))
return this.RenderFileAs(absPath, mimeType)
}
func (this *DirectThumbnailer) RenderFileAs(absPath, mimeType string) ([]byte, error) {
// Decode source
var src image.Image
var err error = nil
if strings.HasPrefix(mimeType, `image/`) {
src, err = this.imageSnapshot(absPath, mimeType)
} else if strings.HasPrefix(mimeType, `video/`) {
src, err = this.videoSnapshot(absPath)
} else {
return nil, ErrUnsupportedFiletype
}
if err != nil {
return nil, err
}
// Scale
dest, err := this.scaleImage(src)
if err != nil {
return nil, err
}
// Rasterise result
return this.encode(dest)
}