feat(#26): support zoom. several refactors and fixes

README.md

@@ -41,10 +41,10 @@ The [install script](https://github.com/lovell/sharp/blob/master/preinstall.sh)
 - Resize
 - Enlarge
 - Crop
-- Rotate
-- Auto-rotate (based on EXIF orientation)
-- Flip
+- Rotate (and auto-rotate based on EXIF orientation)
+- Flip (and auto-flip based on EXIF metadata)
 - Flop
+- Zoom
 - Thumbnail
 - Extract area
 - Format conversion

image.go

@@ -92,6 +92,12 @@ func (i *Image) Watermark(image []byte, left, top int) ([]byte, error) {
 	return i.Process(options)
 }
 
+// Zoom the image by the given factor
+func (i *Image) Zoom(level int) ([]byte, error) {
+	options := Options{Zoom: level}
+	return i.Process(options)
+}
+
 // Rotate the image by given angle degrees (0, 90, 180 or 270)
 func (i *Image) Rotate(a Angle) ([]byte, error) {
 	options := Options{Rotate: a}

image_test.go

@@ -119,16 +119,30 @@ func TestImageWatermark(t *testing.T) {
 
 	err = assertSize(buf, 800, 600)
 	if err != nil {
-		//t.Error(err)
+		t.Error(err)
 	}
 
-	if DetermineImageType(buf) != PNG {
-		//t.Fatal("Image is not jpeg")
+	if DetermineImageType(buf) != JPEG {
+		t.Fatal("Image is not jpeg")
 	}
 
 	Write("fixtures/test_watermark_out.jpg", buf)
 }
 
+func TestImageZoom(t *testing.T) {
+	buf, err := initImage("test.jpg").Zoom(1)
+	if err != nil {
+		t.Errorf("Cannot process the image: %#v", err)
+	}
+
+	err = assertSize(buf, 3360, 2100)
+	if err != nil {
+		t.Error(err)
+	}
+
+	Write("fixtures/test_zoom_out.jpg", buf)
+}
+
 func TestImageFlip(t *testing.T) {
 	buf, err := initImage("test.jpg").Flip()
 	if err != nil {

options.go

@@ -71,6 +71,7 @@ type Options struct {
 	Extend       int
 	Quality      int
 	Compression  int
+	Zoom         int
 	Crop         bool
 	Enlarge      bool
 	Embed        bool

resize.go

@@ -106,6 +106,12 @@ func Resize(buf []byte, o Options) ([]byte, error) {
 		}
 	}
 
+	// Zoom image if necessary
+	image, err = zoomImage(image, o.Zoom)
+	if err != nil {
+		return nil, err
+	}
+
 	// Rotate / flip image if necessary
 	image, err = rotateImage(image, o)
 	if err != nil {
@@ -205,23 +211,31 @@ func insertImage(image *C.struct__VipsImage, t ImageType, o Insert, save vipsSav
 
 	if imageType != t {
 		save.Type = t
-		debug("Image type insert: %s", save.Type)
 		buf, err := vipsSave(insert, save)
 		if err != nil {
 			return nil, err
 		}
+
 		insert, imageType, err = vipsRead(buf)
-		debug("New type image: %s", imageType)
 		if err != nil {
 			return nil, err
 		}
 	}
 
-	debug("Insert images: %#v", insert)
+	debug("Insert image: %#v", insert)
 
 	return vipsInsert(image, insert, o.Left, o.Top)
 }
 
+func zoomImage(image *C.struct__VipsImage, zoom int) (*C.struct__VipsImage, error) {
+	if zoom == 0 {
+		return image, nil
+	}
+	zoom += 1
+
+	return vipsZoom(image, zoom)
+}
+
 func shrinkImage(image *C.struct__VipsImage, o Options, residual float64, shrink int) (*C.struct__VipsImage, float64, error) {
 	// Use vips_shrink with the integral reduction
 	image, err := vipsShrink(image, shrink)

vips.go

@@ -76,7 +76,7 @@ func VipsDebug() {
 	C.im__print_all()
 }
 
-// Get the allocated memory by vips in bytes
+// Get memory info stats from vips
 func VipsMemory() VipsMemoryInfo {
 	return VipsMemoryInfo{
 		Memory:          int64(C.vips_tracked_get_mem()),
@@ -109,14 +109,25 @@ func vipsFlip(image *C.struct__VipsImage, direction Direction) (*C.struct__VipsI
 	return out, nil
 }
 
+func vipsZoom(image *C.struct__VipsImage, zoom int) (*C.struct__VipsImage, error) {
+	var out *C.struct__VipsImage
+	defer C.g_object_unref(C.gpointer(image))
+
+	err := C.vips_zoom_bridge(image, &out, C.int(zoom), C.int(zoom))
+	if err != 0 {
+		return nil, catchVipsError()
+	}
+
+	return out, nil
+}
+
 func vipsInsert(image *C.struct__VipsImage, sub *C.struct__VipsImage, left, top int) (*C.struct__VipsImage, error) {
 	var out *C.struct__VipsImage
-	var cache *C.struct__VipsImage
 
 	defer C.g_object_unref(C.gpointer(image))
 	defer C.g_object_unref(C.gpointer(sub))
 
-	err = C.vips_insert_bridge(image, sub, &out, C.int(left), C.int(top))
+	err := C.vips_insert_bridge(image, sub, &out, C.int(left), C.int(top))
 	if err != 0 {
 		return nil, catchVipsError()
 	}

vips.h

@@ -92,15 +92,15 @@ vips_enum_nick_bridge(VipsImage *image) {
 };
 
 int
-vips_insert_bridge(VipsImage *in, VipsImage *sub, VipsImage **out, int left, int top)
+vips_zoom_bridge(VipsImage *in, VipsImage **out, int xfac, int yfac)
 {
-	return vips_insert(in, sub, out, left, top, NULL);
+	return vips_zoom(in, out, xfac, yfac, NULL);
 };
 
 int
-vips_bandjoin2_bridge(VipsImage *in, VipsImage *sub, VipsImage **out)
+vips_insert_bridge(VipsImage *in, VipsImage *sub, VipsImage **out, int left, int top)
 {
-	return vips_bandjoin2(in, sub, out, NULL);
+	return vips_insert(in, sub, out, left, top, NULL);
 };
 
 int