fix(resize): auto rotate image before resize calculus

resize.go

@@ -32,6 +32,20 @@ func Resize(buf []byte, o Options) ([]byte, error) {
 
 	debug("Options: %#v", o)
 
+	// Auto rotate image based on EXIF orientation header
+	image, rotated, err := rotateAndFlipImage(image, o)
+	if err != nil {
+		return nil, err
+	}
+
+	// If JPEG image, retrieve the buffer
+	if rotated && imageType == JPEG && !o.NoAutoRotate {
+		buf, err = getImageBuffer(image)
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	inWidth := int(image.Xsize)
 	inHeight := int(image.Ysize)
 
@@ -68,12 +82,6 @@ func Resize(buf []byte, o Options) ([]byte, error) {
 		residual = float64(shrink) / factor
 	}
 
-	// Explicit or auto rotate image based on EXIF header
-	image, err = rotateAndFlipImage(image, o)
-	if err != nil {
-		return nil, err
-	}
-
 	// Zoom image, if necessary
 	image, err = zoomImage(image, o.Zoom)
 	if err != nil {
@@ -249,8 +257,9 @@ func extractOrEmbedImage(image *C.VipsImage, o Options) (*C.VipsImage, error) {
 	return image, err
 }
 
-func rotateAndFlipImage(image *C.VipsImage, o Options) (*C.VipsImage, error) {
+func rotateAndFlipImage(image *C.VipsImage, o Options) (*C.VipsImage, bool, error) {
 	var err error
+	var rotated bool
 	var direction Direction = -1
 
 	if o.NoAutoRotate == false {
@@ -264,6 +273,7 @@ func rotateAndFlipImage(image *C.VipsImage, o Options) (*C.VipsImage, error) {
 	}
 
 	if o.Rotate > 0 {
+		rotated = true
 		image, err = vipsRotate(image, getAngle(o.Rotate))
 	}
 
@@ -274,10 +284,11 @@ func rotateAndFlipImage(image *C.VipsImage, o Options) (*C.VipsImage, error) {
 	}
 
 	if direction != -1 {
+		rotated = true
 		image, err = vipsFlip(image, direction)
 	}
 
-	return image, err
+	return image, rotated, err
 }
 
 func watermakImage(image *C.VipsImage, w Watermark) (*C.VipsImage, error) {

resize_test.go

@@ -113,7 +113,7 @@ func TestResizeCustomSizes(t *testing.T) {
 }
 
 func TestRotate(t *testing.T) {
-	options := Options{Width: 800, Height: 600, Rotate: 270}
+	options := Options{Width: 800, Height: 600, Rotate: 270, Crop: true}
 	buf, _ := Read("fixtures/test.jpg")
 
 	newImg, err := Resize(buf, options)
@@ -122,19 +122,19 @@ func TestRotate(t *testing.T) {
 	}
 
 	if DetermineImageType(newImg) != JPEG {
-		t.Fatal("Image is not jpeg")
+		t.Error("Image is not jpeg")
 	}
 
 	size, _ := Size(newImg)
-	if size.Height != options.Width {
+	if size.Width != options.Width || size.Height != options.Height {
-		t.Fatalf("Invalid image size: %dx%d", size.Width, size.Height)
+		t.Errorf("Invalid image size: %dx%d", size.Width, size.Height)
 	}
 
 	Write("fixtures/test_rotate_out.jpg", newImg)
 }
 
-func TestInvalidRotate(t *testing.T) {
+func TestInvalidRotateDegrees(t *testing.T) {
-	options := Options{Width: 800, Height: 600, Rotate: 111}
+	options := Options{Width: 800, Height: 600, Rotate: 111, Crop: true}
 	buf, _ := Read("fixtures/test.jpg")
 
 	newImg, err := Resize(buf, options)
@@ -143,15 +143,15 @@ func TestInvalidRotate(t *testing.T) {
 	}
 
 	if DetermineImageType(newImg) != JPEG {
-		t.Fatal("Image is not jpeg")
+		t.Errorf("Image is not jpeg")
 	}
 
 	size, _ := Size(newImg)
-	if size.Height != options.Width {
+	if size.Width != options.Width || size.Height != options.Height {
-		t.Fatalf("Invalid image size: %dx%d", size.Width, size.Height)
+		t.Errorf("Invalid image size: %dx%d", size.Width, size.Height)
 	}
 
-	Write("fixtures/test_invalid_rotate_out.jpg", newImg)
+	Write("fixtures/test_rotate_invalid_out.jpg", newImg)
 }
 
 func TestCorruptedImage(t *testing.T) {

vips.go

@@ -341,8 +341,23 @@ func vipsSave(image *C.VipsImage, o vipsSaveOptions) ([]byte, error) {
 	return buf, nil
 }
 
-func max(x int) int {
+func getImageBuffer(image *C.VipsImage) ([]byte, error) {
-	return int(math.Max(float64(x), 0))
+	var ptr unsafe.Pointer
+
+	length := C.size_t(0)
+	interlace := C.int(0)
+	quality := C.int(100)
+
+	err := C.int(0)
+	err = C.vips_jpegsave_bridge(image, &ptr, &length, 1, quality, interlace)
+	if int(err) != 0 {
+		return nil, catchVipsError()
+	}
+
+	defer C.g_free(C.gpointer(ptr))
+	defer C.vips_error_clear()
+
+	return C.GoBytes(ptr, C.int(length)), nil
 }
 
 func vipsExtract(image *C.VipsImage, left, top, width, height int) (*C.VipsImage, error) {
@@ -484,3 +499,7 @@ func vipsSharpen(image *C.VipsImage, o Sharpen) (*C.VipsImage, error) {
 	}
 	return out, nil
 }
+
+func max(x int) int {
+	return int(math.Max(float64(x), 0))
+}