feat: extend bimg with support for autorotate

image.go

@@ -154,6 +154,17 @@ func (i *Image) Rotate(a Angle) ([]byte, error) {
 	return i.Process(options)
 }
 
+// AutoRotate the image to be 'up' by default (setting Orientation=1) with vips.
+func (i *Image) AutoRotate() ([]byte, error) {
+	options := Options{AutoRotate: true}
+	image, err := AutoRotate(i.buffer, options)
+	if err != nil {
+		return nil, err
+	}
+	i.buffer = image
+	return image, nil
+}
+
 // Flip flips the image about the vertical Y axis.
 func (i *Image) Flip() ([]byte, error) {
 	options := Options{Flip: true}

options.go

@@ -204,6 +204,7 @@ type Options struct {
 	NoAutoRotate   bool
 	NoProfile      bool
 	Interlace      bool
+	AutoRotate     bool
 	Extend         Extend
 	Rotate         Angle
 	Background     Color

resize.go

@@ -11,6 +11,30 @@ import (
 	"math"
 )
 
+// AutoRotate is a directly calling vips.
+func AutoRotate(buf []byte, o Options) ([]byte, error) {
+	defer C.vips_thread_shutdown()
+
+	image, imageType, err := loadImage(buf)
+	if err != nil {
+		return nil, err
+	}
+
+	// Clone and define default options
+	o = applyDefaults(o, imageType)
+
+	if !IsTypeSupported(o.Type) {
+		return nil, errors.New("Unsupported image output type")
+	}
+
+	image, err = vipsAutoRotate(image)
+	if err != nil {
+		return nil, err
+	}
+
+	return saveImage(image, o)
+}
+
 // Resize is used to transform a given image as byte buffer
 // with the passed options.
 func Resize(buf []byte, o Options) ([]byte, error) {

type_test.go

@@ -26,8 +26,9 @@ func TestDeterminateImageType(t *testing.T) {
 		buf, _ := ioutil.ReadAll(img)
 		defer img.Close()
 
-		if DetermineImageType(buf) != file.expected {
-			t.Fatal("Image type is not valid")
+		actual := DetermineImageType(buf)
+		if actual != file.expected {
+			t.Fatalf("Image type %#v does not equal the expected %#v", actual, file.expected)
 		}
 	}
 }
@@ -51,8 +52,9 @@ func TestDeterminateImageTypeName(t *testing.T) {
 		buf, _ := ioutil.ReadAll(img)
 		defer img.Close()
 
-		if DetermineImageTypeName(buf) != file.expected {
-			t.Fatal("Image type is not valid")
+		actual := DetermineImageTypeName(buf)
+		if actual != file.expected {
+			t.Fatalf("Image type %#v does not equal the expected %#v", actual, file.expected)
 		}
 	}
 }

vips.go

@@ -244,6 +244,18 @@ func vipsRotate(image *C.VipsImage, angle Angle) (*C.VipsImage, error) {
 	return out, nil
 }
 
+func vipsAutoRotate(image *C.VipsImage) (*C.VipsImage, error) {
+	var out *C.VipsImage
+	defer C.g_object_unref(C.gpointer(image))
+
+	err := C.vips_autorotate(image, &out)
+	if err != 0 {
+		return nil, catchVipsError()
+	}
+
+	return out, nil
+}
+
 func vipsFlip(image *C.VipsImage, direction Direction) (*C.VipsImage, error) {
 	var out *C.VipsImage
 	defer C.g_object_unref(C.gpointer(image))

vips.h

@@ -199,6 +199,11 @@ vips_rotate(VipsImage *in, VipsImage **out, int angle) {
 	}
 }
 
+int
+vips_autorotate(VipsImage *in, VipsImage **out) {
+  return vips_autorot(in, out, NULL);
+}
+
 int
 vips_exif_orientation(VipsImage *image) {
 	int orientation = 0;