refactor(thumbnails): separate out 'kovidgoyal/imaging' dependencies

Move code using the 'kovidgoyal/imaging' package to separate files
to make it easier to create alternative implementations based on build
tags.

services/thumbnails/pkg/preprocessor/preprocessor.go

@@ -27,18 +27,6 @@ type FileConverter interface {
 	Convert(r io.Reader) (interface{}, error)
 }
 
-// ImageDecoder is a converter for the image file
-type ImageDecoder struct{}
-
-// Convert reads the image file and returns the thumbnail image
-func (i ImageDecoder) Convert(r io.Reader) (interface{}, error) {
-	img, err := imaging.Decode(r, imaging.AutoOrientation(true))
-	if err != nil {
-		return nil, errors.Wrap(err, `could not decode the image`)
-	}
-	return img, nil
-}
-
 // GifDecoder is a converter for the gif file
 type GifDecoder struct{}
 

services/thumbnails/pkg/preprocessor/preprocessor_imaging.go

@@ -0,0 +1,20 @@
+package preprocessor
+
+import (
+	"io"
+
+	"github.com/kovidgoyal/imaging"
+	"github.com/pkg/errors"
+)
+
+// ImageDecoder is a converter for the image file
+type ImageDecoder struct{}
+
+// Convert reads the image file and returns the thumbnail image
+func (i ImageDecoder) Convert(r io.Reader) (interface{}, error) {
+	img, err := imaging.Decode(r, imaging.AutoOrientation(true))
+	if err != nil {
+		return nil, errors.Wrap(err, `could not decode the image`)
+	}
+	return img, nil
+}

services/thumbnails/pkg/thumbnail/encoding.go

@@ -1,10 +1,7 @@
 package thumbnail
 
 import (
-	"image"
 	"image/gif"
-	"image/jpeg"
-	"image/png"
 	"io"
 	"strings"
 
@@ -29,50 +26,6 @@ type Encoder interface {
 	MimeType() string
 }
 
-// PngEncoder encodes to png
-type PngEncoder struct{}
-
-// Encode encodes to png format
-func (e PngEncoder) Encode(w io.Writer, img interface{}) error {
-	m, ok := img.(image.Image)
-	if !ok {
-		return errors.ErrInvalidType
-	}
-	return png.Encode(w, m)
-}
-
-// Types returns the png suffix
-func (e PngEncoder) Types() []string {
-	return []string{typePng}
-}
-
-// MimeType returns the mimetype for png files.
-func (e PngEncoder) MimeType() string {
-	return "image/png"
-}
-
-// JpegEncoder encodes to jpg
-type JpegEncoder struct{}
-
-// Encode encodes to jpg
-func (e JpegEncoder) Encode(w io.Writer, img interface{}) error {
-	m, ok := img.(image.Image)
-	if !ok {
-		return errors.ErrInvalidType
-	}
-	return jpeg.Encode(w, m, nil)
-}
-
-// Types returns the jpg suffixes.
-func (e JpegEncoder) Types() []string {
-	return []string{typeJpeg, typeJpg}
-}
-
-// MimeType returns the mimetype for jpg files.
-func (e JpegEncoder) MimeType() string {
-	return "image/jpeg"
-}
-
 // GifEncoder encodes to gif
 type GifEncoder struct{}
 

services/thumbnails/pkg/thumbnail/encoding_imaging.go

@@ -0,0 +1,54 @@
+package thumbnail
+
+import (
+	"image"
+	"image/jpeg"
+	"image/png"
+	"io"
+
+	"github.com/owncloud/ocis/v2/services/thumbnails/pkg/errors"
+)
+
+// PngEncoder encodes to png
+type PngEncoder struct{}
+
+// Encode encodes to png format
+func (e PngEncoder) Encode(w io.Writer, img interface{}) error {
+	m, ok := img.(image.Image)
+	if !ok {
+		return errors.ErrInvalidType
+	}
+	return png.Encode(w, m)
+}
+
+// Types returns the png suffix
+func (e PngEncoder) Types() []string {
+	return []string{typePng}
+}
+
+// MimeType returns the mimetype for png files.
+func (e PngEncoder) MimeType() string {
+	return "image/png"
+}
+
+// JpegEncoder encodes to jpg
+type JpegEncoder struct{}
+
+// Encode encodes to jpg
+func (e JpegEncoder) Encode(w io.Writer, img interface{}) error {
+	m, ok := img.(image.Image)
+	if !ok {
+		return errors.ErrInvalidType
+	}
+	return jpeg.Encode(w, m, nil)
+}
+
+// Types returns the jpg suffixes.
+func (e JpegEncoder) Types() []string {
+	return []string{typeJpeg, typeJpg}
+}
+
+// MimeType returns the mimetype for jpg files.
+func (e JpegEncoder) MimeType() string {
+	return "image/jpeg"
+}

services/thumbnails/pkg/thumbnail/generator.go

@@ -14,44 +14,17 @@ import (
 // Generator generates a web friendly file version.
 type Generator interface {
 	Generate(size image.Rectangle, img interface{}) (interface{}, error)
+	Dimensions(img interface{}) (image.Rectangle, error)
 	ProcessorID() string
 }
 
-// SimpleGenerator is the default image generator and is used for all image types expect gif.
-type SimpleGenerator struct {
-	processor Processor
-}
-
-func NewSimpleGenerator(filetype, process string) (SimpleGenerator, error) {
-	processor, err := ProcessorFor(filetype, process)
-	if err != nil {
-		return SimpleGenerator{}, err
-	}
-	return SimpleGenerator{processor: processor}, nil
-}
-
-// ProcessorID returns the processor identification.
-func (g SimpleGenerator) ProcessorID() string {
-	return g.processor.ID()
-}
-
-// Generate generates a alternative image version.
-func (g SimpleGenerator) Generate(size image.Rectangle, img interface{}) (interface{}, error) {
-	m, ok := img.(image.Image)
-	if !ok {
-		return nil, errors.ErrInvalidType
-	}
-
-	return g.processor.Process(m, size.Dx(), size.Dy(), imaging.Lanczos), nil
-}
-
 // GifGenerator is used to create a web friendly version of the provided gif image.
 type GifGenerator struct {
 	processor Processor
 }
 
 func NewGifGenerator(filetype, process string) (GifGenerator, error) {
-	processor, err := ProcessorFor(filetype, process)
+	processor, err := ProcessorFor(process, filetype)
 	if err != nil {
 		return GifGenerator{}, err
 	}
@@ -97,6 +70,14 @@ func (g GifGenerator) Generate(size image.Rectangle, img interface{}) (interface
 	return m, nil
 }
 
+func (g GifGenerator) Dimensions(img interface{}) (image.Rectangle, error) {
+	m, ok := img.(*gif.GIF)
+	if !ok {
+		return image.Rectangle{}, errors.ErrInvalidType
+	}
+	return m.Image[0].Bounds(), nil
+}
+
 func (g GifGenerator) imageToPaletted(img image.Image, p color.Palette) *image.Paletted {
 	b := img.Bounds()
 	pm := image.NewPaletted(b, p)

services/thumbnails/pkg/thumbnail/generator_simple.go

@@ -0,0 +1,44 @@
+package thumbnail
+
+import (
+	"image"
+
+	"github.com/kovidgoyal/imaging"
+	"github.com/owncloud/ocis/v2/services/thumbnails/pkg/errors"
+)
+
+// SimpleGenerator is the default image generator and is used for all image types expect gif.
+type SimpleGenerator struct {
+	processor Processor
+}
+
+func NewSimpleGenerator(filetype, process string) (SimpleGenerator, error) {
+	processor, err := ProcessorFor(process, filetype)
+	if err != nil {
+		return SimpleGenerator{}, err
+	}
+	return SimpleGenerator{processor: processor}, nil
+}
+
+// ProcessorID returns the processor identification.
+func (g SimpleGenerator) ProcessorID() string {
+	return g.processor.ID()
+}
+
+// Generate generates a alternative image version.
+func (g SimpleGenerator) Generate(size image.Rectangle, img interface{}) (interface{}, error) {
+	m, ok := img.(image.Image)
+	if !ok {
+		return nil, errors.ErrInvalidType
+	}
+
+	return g.processor.Process(m, size.Dx(), size.Dy(), imaging.Lanczos), nil
+}
+
+func (g SimpleGenerator) Dimensions(img interface{}) (image.Rectangle, error) {
+	m, ok := img.(image.Image)
+	if !ok {
+		return image.Rectangle{}, errors.ErrInvalidType
+	}
+	return m.Bounds(), nil
+}

services/thumbnails/pkg/thumbnail/thumbnail.go

@@ -3,7 +3,6 @@ package thumbnail
 import (
 	"bytes"
 	"image"
-	"image/gif"
 	"mime"
 
 	"github.com/owncloud/ocis/v2/ocis-pkg/log"
@@ -70,15 +69,12 @@ type SimpleManager struct {
 // Generate creates a thumbnail and stores it
 func (s SimpleManager) Generate(r Request, img interface{}) (string, error) {
 	var match image.Rectangle
-	var inputDimensions image.Rectangle
-	switch m := img.(type) {
-	case *gif.GIF:
-		match = s.resolutions.ClosestMatch(r.Resolution, m.Image[0].Bounds())
-		inputDimensions = m.Image[0].Bounds()
-	case image.Image:
-		match = s.resolutions.ClosestMatch(r.Resolution, m.Bounds())
-		inputDimensions = m.Bounds()
+
+	inputDimensions, err := r.Generator.Dimensions(img)
+	if err != nil {
+		return "", err
 	}
+	match = s.resolutions.ClosestMatch(r.Resolution, inputDimensions)
 
 	// validate max input image dimensions - 6016x4000
 	if inputDimensions.Size().X > s.maxDimension.X || inputDimensions.Size().Y > s.maxDimension.Y {

services/thumbnails/pkg/thumbnail/thumbnail_test.go

@@ -183,6 +183,10 @@ func TestPreviewGenerationTooBigImage(t *testing.T) {
 
 			ext := path.Ext(tt.fileName)
 			req.Encoder, _ = EncoderForType(ext)
+			req.Generator, err = GeneratorFor(ext, "fit")
+			if err != nil {
+				return
+			}
 			generate, err := sut.Generate(req, convert)
 			if err != nil {
 				return