set custom output/aspect/scale formats, add package-level error vars

Thumbnailer.go

@@ -1,7 +1,7 @@
 package thumbnail
 
 import (
-	"fmt"
+	"errors"
 	"image/gif"
 	"image/jpeg"
 	"image/png"
@@ -12,22 +12,55 @@ import (
 	lru "github.com/hashicorp/golang-lru"
 )
 
+type OutputFormat uint8
+type AspectFormat uint8
+type ScaleFormat uint8
+
+const (
+	OUTPUT_PNG_CRUSH OutputFormat = 2
+	OUTPUT_JPG       OutputFormat = 3
+	OUTPUT__DEFAULT               = OUTPUT_PNG_CRUSH
+
+	ASPECT_PADDED   AspectFormat = 80
+	ASPECT_SVELTE   AspectFormat = 81
+	ASPECT__DEFAULT              = ASPECT_PADDED
+
+	SCALEFMT_NN       ScaleFormat = 120
+	SCALEFMT_BILINEAR ScaleFormat = 121
+	SCALEFMT__DEFAULT             = SCALEFMT_BILINEAR
+)
+
+var (
+	ErrInvalidOption       error = errors.New("Invalid format parameter")
+	ErrUnsupportedFiletype error = errors.New("Unsupported filetype")
+)
+
 type Thumbnailer struct {
-	Width  int
+	width  int
-	Height int
+	height int
+	ofmt   OutputFormat
+	afmt   AspectFormat
+	sfmt   ScaleFormat
 
 	thumbCache *lru.Cache // threadsafe
 }
 
 func NewThumbnailer(Width, Height, MaxCacheSize int) *Thumbnailer {
+	return NewThumbnailerEx(Width, Height, MaxCacheSize, OUTPUT__DEFAULT, ASPECT__DEFAULT, SCALEFMT__DEFAULT)
+}
+
+func NewThumbnailerEx(Width, Height, MaxCacheSize int, of OutputFormat, af AspectFormat, sf ScaleFormat) *Thumbnailer {
 	thumbCache, err := lru.New(MaxCacheSize)
 	if err != nil {
 		panic(err)
 	}
 
 	return &Thumbnailer{
-		Width:      Width,
+		width:      Width,
-		Height:     Height,
+		height:     Height,
+		ofmt:       of,
+		afmt:       af,
+		sfmt:       sf,
 		thumbCache: thumbCache,
 	}
 }
@@ -98,7 +131,7 @@ func (this *Thumbnailer) RenderFile_NoCache(absPath string) ([]byte, error) {
 		return this.RenderScaledFfmpeg(absPath)
 
 	default:
-		return nil, fmt.Errorf("No thumbnailer for file type '%s'", extension)
+		return nil, ErrUnsupportedFiletype
 
 	}
 

image.go

@@ -1,7 +1,9 @@
 package thumbnail
 
 import (
+	"bytes"
 	"image"
+	"image/jpeg"
 
 	"code.ivysaur.me/imagequant"
 )
@@ -13,32 +15,27 @@ func (this *Thumbnailer) RenderScaledImage(src image.Image) ([]byte, error) {
 	destH := 0
 
 	if srcW > srcH {
-		destW = this.Width
+		destW = this.width
-		destH = this.Height * srcH / srcW
+		destH = this.height * srcH / srcW
 	} else {
-		destW = this.Width * srcW / srcH
+		destW = this.width * srcW / srcH
-		destH = this.Height
+		destH = this.height
 	}
 
-	offsetX := (this.Width - destW) / 2
+	offsetX := (this.width - destW) / 2
-	offsetY := (this.Height - destH) / 2
+	offsetY := (this.height - destH) / 2
 
 	scaleW := float64(srcW) / float64(destW)
 	scaleH := float64(srcH) / float64(destH)
 
-	dest := image.NewRGBA(image.Rectangle{Max: image.Point{X: this.Width, Y: this.Height}})
+	dest := image.NewRGBA(image.Rectangle{Max: image.Point{X: this.width, Y: this.height}})
+
+	switch this.sfmt {
+
+	case SCALEFMT_BILINEAR:
 
 		for y := 0; y < destH; y += 1 {
 			for x := 0; x < destW; x += 1 {
-
-			/*
-				// NN
-				mapx := int(float64(x) * scaleW)
-				mapy := int(float64(y) * scaleH)
-				dest.Set(x+offsetX, y+offsetY, src.At(mapx, mapy))
-			*/
-
-			// Bilinear
 				c00 := src.At(int(float64(x)*scaleW), int(float64(y)*scaleH))
 				c01 := src.At(int((float64(x)+0.5)*scaleW), int(float64(y)*scaleH))
 				c10 := src.At(int(float64(x)*scaleW), int((float64(y)+0.5)*scaleH))
@@ -49,5 +46,34 @@ func (this *Thumbnailer) RenderScaledImage(src image.Image) ([]byte, error) {
 			}
 		}
 
+	case SCALEFMT_NN:
+
+		for y := 0; y < destH; y += 1 {
+			for x := 0; x < destW; x += 1 {
+				mapx := int(float64(x) * scaleW)
+				mapy := int(float64(y) * scaleH)
+				dest.Set(x+offsetX, y+offsetY, src.At(mapx, mapy))
+			}
+		}
+
+	}
+
+	switch this.ofmt {
+	case OUTPUT_PNG_CRUSH:
 		return crush(dest, imagequant.SPEED_FASTEST)
+
+	case OUTPUT_JPG:
+		buff := bytes.Buffer{}
+		err := jpeg.Encode(&buff, dest, &jpeg.Options{Quality: jpeg.DefaultQuality})
+		if err != nil {
+			return nil, err
+		}
+
+		return buff.Bytes(), nil
+
+	default:
+		return nil, ErrInvalidOption
+
+	}
+
 }

video.go

@@ -11,10 +11,22 @@ func (this *Thumbnailer) RenderScaledFfmpeg(absPath string) ([]byte, error) {
 
 	scaleCmd := fmt.Sprintf(
 		`thumbnail,scale='if(gt(a,%d/%d),%d,-1)':'if(gt(a,%d/%d),-1,%d)'`,
-		this.Height, this.Width, this.Height,
+		this.height, this.width, this.height,
-		this.Height, this.Width, this.Width,
+		this.height, this.width, this.width,
 	)
 
+	// BUG(): always produces ASPECT_SVELTE shape - need to re-pad for ASPECT_PADDED
+
+	var vcodec string
+	switch this.ofmt {
+	case OUTPUT_JPG:
+		vcodec = "jpg"
+	case OUTPUT_PNG_CRUSH:
+		vcodec = "png"
+	default:
+		return nil, ErrInvalidOption
+	}
+
 	cmd := exec.Command(
 		"ffmpeg",
 		"-loglevel", "0",
@@ -23,7 +35,7 @@ func (this *Thumbnailer) RenderScaledFfmpeg(absPath string) ([]byte, error) {
 		"-vf", scaleCmd,
 		"-frames:v", "1",
 		"-f", "image2pipe",
-		"-c:v", "png",
+		"-c:v", vcodec,
 		"-",
 	)