Merge pull request #156 from Dynom/SmartCropToGravity

Replacing SmartCrop with a Gravity option

image.go

@@ -44,10 +44,10 @@ func (i *Image) ResizeAndCrop(width, height int) ([]byte, error) {
 // SmartCrop produces a thumbnail aiming at focus on the interesting part.
 func (i *Image) SmartCrop(width, height int) ([]byte, error) {
 	options := Options{
-		Width:     width,
-		Height:    height,
-		Crop:      true,
-		SmartCrop: true,
+		Width:   width,
+		Height:  height,
+		Crop:    true,
+		Gravity: GravitySmart,
 	}
 	return i.Process(options)
 }

image_test.go

@@ -456,20 +456,23 @@ func TestFluentInterface(t *testing.T) {
 }
 
 func TestImageSmartCrop(t *testing.T) {
-	if VipsMajorVersion >= 8 && VipsMinorVersion > 4 {
-		i := initImage("northern_cardinal_bird.jpg")
-		buf, err := i.SmartCrop(300, 300)
-		if err != nil {
-			t.Errorf("Cannot process the image: %#v", err)
-		}
 
-		err = assertSize(buf, 300, 300)
-		if err != nil {
-			t.Error(err)
-		}
-
-		Write("fixtures/test_smart_crop.jpg", buf)
+	if !(VipsMajorVersion >= 8 && VipsMinorVersion > 4) {
+		t.Skipf("Skipping this test, libvips doesn't meet version requirement %s > 8.4", VipsVersion)
 	}
+
+	i := initImage("northern_cardinal_bird.jpg")
+	buf, err := i.SmartCrop(300, 300)
+	if err != nil {
+		t.Errorf("Cannot process the image: %#v", err)
+	}
+
+	err = assertSize(buf, 300, 300)
+	if err != nil {
+		t.Error(err)
+	}
+
+	Write("fixtures/test_smart_crop.jpg", buf)
 }
 
 func initImage(file string) *Image {

options.go

@@ -27,6 +27,8 @@ const (
 	GravitySouth
 	// GravityWest represents the west value used for image gravity orientation.
 	GravityWest
+	// GravitySmart enables libvips Smart Crop algorithm for image gravity orientation.
+	GravitySmart
 )
 
 // Interpolator represents the image interpolation value.
@@ -193,7 +195,7 @@ type Options struct {
 	Compression    int
 	Zoom           int
 	Crop           bool
-	SmartCrop      bool
+	SmartCrop      bool // Deprecated
 	Enlarge        bool
 	Embed          bool
 	Flip           bool

resize.go

@@ -249,7 +249,7 @@ func extractOrEmbedImage(image *C.VipsImage, o Options) (*C.VipsImage, error) {
 	inHeight := int(image.Ysize)
 
 	switch {
-	case o.SmartCrop:
+	case o.Gravity == GravitySmart, o.SmartCrop:
 		image, err = vipsSmartCrop(image, o.Width, o.Height)
 		break
 	case o.Crop:

resize_test.go

@@ -2,6 +2,7 @@ package bimg
 
 import (
 	"bytes"
+	"crypto/md5"
 	"image"
 	"image/jpeg"
 	"io/ioutil"
@@ -392,6 +393,51 @@ func TestResizePngWithTransparency(t *testing.T) {
 	Write("fixtures/transparent_out.png", newImg)
 }
 
+func TestIfBothSmartCropOptionsAreIdentical(t *testing.T) {
+	if !(VipsMajorVersion >= 8 && VipsMinorVersion > 4) {
+		t.Skipf("Skipping this test, libvips doesn't meet version requirement %s > 8.4", VipsVersion)
+	}
+
+	benchmarkOptions := Options{Width: 100, Height: 100, Crop: true}
+	smartCropOptions := Options{Width: 100, Height: 100, Crop: true, SmartCrop: true}
+	gravityOptions := Options{Width: 100, Height: 100, Crop: true, Gravity: GravitySmart}
+
+	testImg, err := os.Open("fixtures/northern_cardinal_bird.jpg")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer testImg.Close()
+
+	testImgByte, err := ioutil.ReadAll(testImg)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	scImg, err := Resize(testImgByte, smartCropOptions)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	gImg, err := Resize(testImgByte, gravityOptions)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	benchmarkImg, err := Resize(testImgByte, benchmarkOptions)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	sch, gh, bh := md5.Sum(scImg), md5.Sum(gImg), md5.Sum(benchmarkImg)
+	if gh == bh || sch == bh {
+		t.Error("Expected both options produce a different result from a standard crop.")
+	}
+
+	if sch != gh {
+		t.Errorf("Expected both options to result in the same output, %x != %x", sch, gh)
+	}
+}
+
 func runBenchmarkResize(file string, o Options, b *testing.B) {
 	buf, _ := Read(path.Join("fixtures", file))