Restructure and simplify options etc.

Author: bep

internal/libwebp/a__encoder.go

@@ -38,24 +38,24 @@ import (
 	"image/draw"
 	"io"
 	"unsafe"
+
+	"github.com/bep/gowebp/libwebp/options"
 )
 
 type (
 	Encoder struct {
-		options *Options
-		config  *C.WebPConfig
-		img     *image.NRGBA
+		config *C.WebPConfig
+		img    *image.NRGBA
 	}
 )
 
-func NewEncoder(src image.Image, options *Options) (e *Encoder, err error) {
-	var config *C.WebPConfig
-
-	if config, err = options.GetConfig(); err != nil {
+func NewEncoder(src image.Image, options options.EncodingOptions) (*Encoder, error) {
+	config, err := encodingOptionsToCConfig(options)
+	if err != nil {
 		return nil, err
 	}
 
-	e = &Encoder{options: options, config: config}
+	e := &Encoder{config: config}
 
 	switch v := src.(type) {
 	case *image.NRGBA:
@@ -64,7 +64,7 @@ func NewEncoder(src image.Image, options *Options) (e *Encoder, err error) {
 		e.img = e.convertToNRGBA(src)
 	}
 
-	return
+	return e, nil
 }
 
 func (e *Encoder) Encode(w io.Writer) error {
@@ -89,9 +89,27 @@ func (e *Encoder) Encode(w io.Writer) error {
 	return err
 }
 
-func (e *Encoder) convertToNRGBA(src image.Image) (dst *image.NRGBA) {
-	dst = image.NewNRGBA(src.Bounds())
+func (e *Encoder) convertToNRGBA(src image.Image) *image.NRGBA {
+	dst := image.NewNRGBA(src.Bounds())
 	draw.Draw(dst, dst.Bounds(), src, src.Bounds().Min, draw.Src)
 
-	return
+	return dst
+}
+
+func encodingOptionsToCConfig(o options.EncodingOptions) (*C.WebPConfig, error) {
+	cfg := &C.WebPConfig{}
+	quality := C.float(o.Quality)
+
+	if C.WebPConfigPreset(cfg, C.WebPPreset(o.EncodingPreset), quality) == 0 {
+		return nil, errors.New("failed to init encoder config")
+	}
+
+	cfg.quality = quality
+
+	if C.WebPValidateConfig(cfg) == 0 {
+		return nil, errors.New("failed to validate config")
+	}
+
+	return cfg, nil
+
 }

internal/libwebp/a__options.go

@@ -0,0 +1,19 @@
+package libwebp
+
+import (
+	"image"
+	"io"
+
+	"github.com/bep/gowebp/libwebp/options"
+
+	"github.com/bep/gowebp/internal/libwebp"
+)
+
+// Encode encodes src as Webp into w using the options in o.
+func Encode(w io.Writer, src image.Image, o options.EncodingOptions) error {
+	if enc, err := libwebp.NewEncoder(src, o); err != nil {
+		return err
+	} else {
+		return enc.Encode(w)
+	}
+}

libwebp/encode.go

@@ -0,0 +1,86 @@
+package libwebp
+
+import (
+	"image/jpeg"
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/bep/gowebp/libwebp/options"
+)
+
+func TestEncode(t *testing.T) {
+	t.Run("encode lossy", func(t *testing.T) {
+		r, err := os.Open("../test_data/images/source.jpg")
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		img, err := jpeg.Decode(r)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if err = Encode(ioutil.Discard, img, options.EncodingOptions{}); err != nil {
+			t.Fatal(err)
+		}
+	})
+	t.Run("encode lossless", func(t *testing.T) {
+		r, err := os.Open("../test_data/images/source.jpg")
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		img, err := jpeg.Decode(r)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if err = Encode(ioutil.Discard, img, options.EncodingOptions{Quality: 75}); err != nil {
+			t.Fatal(err)
+		}
+	})
+}
+
+func BenchmarkEncode(b *testing.B) {
+	r, err := os.Open("../test_data/images/source.jpg")
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	img, err := jpeg.Decode(r)
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	opts := options.EncodingOptions{Quality: 75}
+
+	for i := 0; i < b.N; i++ {
+		if err = Encode(ioutil.Discard, img, opts); err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+// Just to have something to compare with.
+func BenchmarkEncodeJpeg(b *testing.B) {
+	r, err := os.Open("../test_data/images/source.jpg")
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	img, err := jpeg.Decode(r)
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	opts := &jpeg.Options{
+		Quality: 75,
+	}
+
+	for i := 0; i < b.N; i++ {
+		if err = jpeg.Encode(ioutil.Discard, img, opts); err != nil {
+			b.Fatal(err)
+		}
+	}
+}

libwebp/encode_test.go

@@ -0,0 +1,22 @@
+package options
+
+const (
+	PresetDefault EncodingPreset = iota
+	PresetPicture
+	PresetPhoto
+	PresetDrawing
+	PresetIcon
+	PresetText
+)
+
+type (
+	EncodingPreset int
+	EncodingOptions        struct {
+
+		// Quality is a number between 0 and 100. Set to 0 for lossless.
+		Quality int
+
+		// The encoding preset to use.
+		EncodingPreset
+	}
+)