feat(#6, #10, #11)

image.go

@@ -1,12 +1,46 @@
 package bimg
 
-/*
-#cgo pkg-config: vips
-#include "vips/vips.h"
-*/
-import "C"
-
 type Image struct {
-	buf   []byte
+	buffer []byte
-	image *C.struct__VipsImage
+}
+
+func (i *Image) Resize(width int, height int) ([]byte, error) {
+	options := Options{
+		Width:  width,
+		Height: height,
+	}
+	return Resize(i.buffer, options)
+}
+
+func (i *Image) Extract(top int, left int, width int, height int) ([]byte, error) {
+	options := Options{
+		Width:  width,
+		Height: height,
+		Top:    top,
+		Left:   left,
+	}
+	return Resize(i.buffer, options)
+}
+
+func (i *Image) Rotate(degrees Angle) ([]byte, error) {
+	options := Options{Rotate: degrees}
+	return Resize(i.buffer, options)
+}
+
+func (i *Image) Flip() ([]byte, error) {
+	options := Options{Flip: VERTICAL}
+	return Resize(i.buffer, options)
+}
+
+func (i *Image) Flop() ([]byte, error) {
+	options := Options{Flip: HORIZONTAL}
+	return Resize(i.buffer, options)
+}
+
+func (i *Image) Type() string {
+	return DetermineImageTypeName(i.buffer)
+}
+
+func NewImage(buf []byte) *Image {
+	return &Image{buf}
 }

options.go

@@ -22,18 +22,14 @@ func (i Interpolator) String() string {
 	return interpolations[i]
 }
 
-type Rotation struct {
+type Angle int
-	angle int
-}
 
-func (a Rotation) calculate() int {
+const (
-	angle := a.angle
+	D0   Angle = C.VIPS_ANGLE_D0
-	divisor := angle % 90
+	D90  Angle = C.VIPS_ANGLE_D90
-	if divisor != 0 {
+	D180 Angle = C.VIPS_ANGLE_D180
-		angle = a.angle - divisor
+	D270 Angle = C.VIPS_ANGLE_D270
-	}
+)
-	return angle
-}
 
 type Direction int
 
@@ -45,12 +41,14 @@ const (
 type Options struct {
 	Height       int
 	Width        int
+	Top          int
+	Left         int
 	Crop         bool
 	Enlarge      bool
 	Extend       int
 	Embed        bool
 	Quality      int
-	Rotate       int
+	Rotate       Angle
 	Flip         Direction
 	Gravity      Gravity
 	Interpolator Interpolator

resize.go

@@ -16,8 +16,15 @@ const (
 	NOHALO
 )
 
+const (
+	CENTRE Gravity = iota
+	NORTH
+	EAST
+	SOUTH
+	WEST
+)
+
 func Resize(buf []byte, o Options) ([]byte, error) {
-	// detect (if possible) the file type
 	defer C.vips_thread_shutdown()
 
 	image, err := vipsRead(buf)
@@ -34,7 +41,6 @@ func Resize(buf []byte, o Options) ([]byte, error) {
 	inWidth := int(image.Xsize)
 	inHeight := int(image.Ysize)
 
-	// crop
 	if o.Crop {
 		left, top := calculateCrop(inWidth, inHeight, o.Width, o.Height, o.Gravity)
 		o.Width = int(math.Min(float64(inWidth), float64(o.Width)))
@@ -45,9 +51,24 @@ func Resize(buf []byte, o Options) ([]byte, error) {
 		}
 	}
 
-	// rotate
+	rotation, flip := calculateRotationAndFlip(image, o.Rotate)
+	if flip {
+		o.Flip = HORIZONTAL
+	}
+	if rotation != D0 {
+		o.Rotate = rotation
+	}
+
 	if o.Rotate > 0 {
-		image, err = Rotate(image, Rotation{o.Rotate})
+		rotation := calculateRotation(o.Rotate)
+		image, err = vipsRotate(image, rotation)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if o.Flip > 0 {
+		image, err = vipsFlip(image, o.Flip)
 		if err != nil {
 			return nil, err
 		}
@@ -62,21 +83,9 @@ func Resize(buf []byte, o Options) ([]byte, error) {
 	return buf, nil
 }
 
-func Rotate(image *C.struct__VipsImage, r Rotation) (*C.struct__VipsImage, error) {
-	//vips := &Vips{}
-	return vipsRotate(image, r.calculate())
-}
-
-const (
-	CENTRE Gravity = iota
-	NORTH
-	EAST
-	SOUTH
-	WEST
-)
-
 func calculateCrop(inWidth, inHeight, outWidth, outHeight int, gravity Gravity) (int, int) {
 	left, top := 0, 0
+
 	switch gravity {
 	case NORTH:
 		left = (inWidth - outWidth + 1) / 2
@@ -92,5 +101,58 @@ func calculateCrop(inWidth, inHeight, outWidth, outHeight int, gravity Gravity)
 		left = (inWidth - outWidth + 1) / 2
 		top = (inHeight - outHeight + 1) / 2
 	}
+
 	return left, top
 }
+
+func calculateRotationAndFlip(image *C.struct__VipsImage, angle Angle) (Angle, bool) {
+	rotate := D0
+	flip := false
+
+	if angle == -1 {
+		switch vipsExifOrientation(image) {
+		case 6:
+			rotate = D90
+			break
+		case 3:
+			rotate = D180
+			break
+		case 8:
+			rotate = D270
+			break
+		case 2:
+			flip = true
+			break // flip 1
+		case 7:
+			flip = true
+			rotate = D90
+			break // flip 6
+		case 4:
+			flip = true
+			rotate = D180
+			break // flip 3
+		case 5:
+			flip = true
+			rotate = D270
+			break // flip 8
+		}
+	} else {
+		if angle == 90 {
+			rotate = D90
+		} else if angle == 180 {
+			rotate = D180
+		} else if angle == 270 {
+			rotate = D270
+		}
+	}
+
+	return rotate, flip
+}
+
+func calculateRotation(angle Angle) Angle {
+	divisor := angle % 90
+	if divisor != 0 {
+		angle = angle - divisor
+	}
+	return angle
+}

vips.go

@@ -13,7 +13,7 @@ import (
 	"unsafe"
 )
 
-type vipsImage *C.struct__VipsImage
+type vipsImage C.struct__VipsImage
 
 func init() {
 	runtime.LockOSThread()
@@ -34,13 +34,13 @@ type Vips struct {
 	buf []byte
 }
 
-func vipsRotate(image *C.struct__VipsImage, degrees int) (*C.struct__VipsImage, error) {
+func vipsRotate(image *C.struct__VipsImage, angle Angle) (*C.struct__VipsImage, error) {
 	var out *C.struct__VipsImage
 
-	err := C.vips_rotate(image, &out, C.int(degrees))
+	err := C.vips_rotate(image, &out, C.int(angle))
 	C.g_object_unref(C.gpointer(image))
 	if err != 0 {
-		return nil, vipsError()
+		return nil, catchVipsError()
 	}
 	defer C.g_object_unref(C.gpointer(out))
 
@@ -53,7 +53,7 @@ func vipsFlip(image *C.struct__VipsImage, direction Direction) (*C.struct__VipsI
 	err := C.vips_flip_seq(image, &out)
 	C.g_object_unref(C.gpointer(image))
 	if err != 0 {
-		return nil, vipsError()
+		return nil, catchVipsError()
 	}
 	defer C.g_object_unref(C.gpointer(out))
 
@@ -74,9 +74,8 @@ func vipsRead(buf []byte) (*C.struct__VipsImage, error) {
 	imageTypeC := C.int(imageType)
 
 	err := C.vips_init_image(imageBuf, length, imageTypeC, &image)
-	//err := C.vips_jpegload_buffer_seq(imageBuf, length, &image)
 	if err != 0 {
-		return nil, vipsError()
+		return nil, catchVipsError()
 	}
 
 	return image, nil
@@ -88,7 +87,7 @@ func vipsExtract(image *C.struct__VipsImage, left int, top int, width int, heigh
 	err := C.vips_extract_area_0(image, &buf, C.int(left), C.int(top), C.int(width), C.int(height))
 	C.g_object_unref(C.gpointer(image))
 	if err != 0 {
-		return nil, vipsError()
+		return nil, catchVipsError()
 	}
 
 	return buf, nil
@@ -122,6 +121,10 @@ func vipsImageType(buf []byte) int {
 	return imageType
 }
 
+func vipsExifOrientation(image *C.struct__VipsImage) int {
+	return int(C.vips_exif_orientation(image))
+}
+
 type vipsSaveOptions struct {
 	Quality int
 }
@@ -132,7 +135,7 @@ func vipsSave(image *C.struct__VipsImage, o vipsSaveOptions) ([]byte, error) {
 
 	err := C.vips_jpegsave_custom(image, &ptr, &length, 1, C.int(o.Quality), 0)
 	if err != 0 {
-		return nil, vipsError()
+		return nil, catchVipsError()
 	}
 	C.g_object_unref(C.gpointer(image))
 
@@ -143,7 +146,7 @@ func vipsSave(image *C.struct__VipsImage, o vipsSaveOptions) ([]byte, error) {
 	return buf, nil
 }
 
-func vipsError() error {
+func catchVipsError() error {
 	s := C.GoString(C.vips_error_buffer())
 	C.vips_error_clear()
 	C.vips_thread_shutdown()

vips.h

@@ -11,6 +11,12 @@ enum types {
 	MAGICK
 };
 
+void
+vips_malloc_cb(VipsObject *object, char *buf)
+{
+	g_free(buf);
+};
+
 int
 vips_affine_interpolator(VipsImage *in, VipsImage **out, double a, double b, double c, double d, VipsInterpolate *interpolator)
 {
@@ -94,9 +100,27 @@ vips_init_image(void *buf, size_t len, int imageType, VipsImage **out) {
 #endif
   }
 
+  if (out != NULL) {
+  	// Listen for "postclose" signal to delete input buffer
+  	//g_signal_connect(out, "postclose", G_CALLBACK(vips_malloc_cb), buf);
+	}
+
   return code;
 };
 
+int
+vips_exif_orientation(VipsImage *image) {
+  int orientation = 0;
+  const char **exif;
+  if (
+    vips_image_get_typeof(image, "exif-ifd0-Orientation") != 0 &&
+    !vips_image_get_string(image, "exif-ifd0-Orientation", exif)
+  ) {
+    orientation = atoi(exif[0]);
+  }
+  return orientation;
+};
+
 int
 vips_embed_extend(VipsImage *in, VipsImage **out, int left, int top, int width, int height, int extend)
 {