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,
+		Width:   width,
-		Height:    height,
+		Height:  height,
-		Crop:      true,
+		Crop:    true,
-		SmartCrop: true,
+		Gravity: GravitySmart,
 	}
 	return i.Process(options)
 }

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 +195,6 @@ type Options struct {
 	Compression    int
 	Zoom           int
 	Crop           bool
-	SmartCrop      bool
 	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:
 		image, err = vipsSmartCrop(image, o.Width, o.Height)
 		break
 	case o.Crop: