fix ResizeWithVScale and remove code duplication (#47)

vips/image.go

@@ -1168,12 +1168,18 @@ func (r *ImageRef) Rank(width int, height int, index int) error {
 
 // Resize resizes the image based on the scale, maintaining aspect ratio
 func (r *ImageRef) Resize(scale float64, kernel Kernel) error {
+	return r.ResizeWithVScale(scale, -1, kernel)
+}
+
+// ResizeWithVScale resizes the image with both horizontal as well as vertical scaling.
+// The parameters are the scaling factors.
+func (r *ImageRef) ResizeWithVScale(hScale, vScale float64, kernel Kernel) error {
 	err := r.PremultiplyAlpha()
 	if err != nil {
 		return err
 	}
 
-	out, err := vipsResize(r.image, scale, kernel)
+	out, err := vipsResizeWithVScale(r.image, hScale, vScale, kernel)
 	if err != nil {
 		return err
 	}
@@ -1182,17 +1188,6 @@ func (r *ImageRef) Resize(scale float64, kernel Kernel) error {
 	return r.UnpremultiplyAlpha()
 }
 
-// ResizeWithVScale resizes the image with both horizontal as well as vertical scaling.
-// The parameters are the scaling factors.
-func (r *ImageRef) ResizeWithVScale(hScale, vScale float64, kernel Kernel) error {
-	out, err := vipsResizeWithVScale(r.image, hScale, vScale, kernel)
-	if err != nil {
-		return err
-	}
-	r.setImage(out)
-	return nil
-}
-
 // Thumbnail resizes the image to the given width and height.
 // If crop is true the returned image size will be exactly the given height and width,
 // otherwise the width and height will be within the given parameters.

vips/resample.go

@@ -18,7 +18,7 @@ const (
 )
 
 // https://libvips.github.io/libvips/API/current/libvips-resample.html#vips-resize
-func vipsResize(in *C.VipsImage, scale float64, kernel Kernel) (*C.VipsImage, error) {
+func vipsResizeWithVScale(in *C.VipsImage, hscale, vscale float64, kernel Kernel) (*C.VipsImage, error) {
 	incOpCounter("resize")
 	var out *C.VipsImage
 
@@ -27,19 +27,7 @@ func vipsResize(in *C.VipsImage, scale float64, kernel Kernel) (*C.VipsImage, er
 		kernel = KernelLanczos3
 	}
 
-	if err := C.resize_image(in, &out, C.double(scale), C.double(-1), C.int(kernel)); err != 0 {
-		return nil, handleImageError(out)
-	}
-
-	return out, nil
-}
-
-// https://libvips.github.io/libvips/API/current/libvips-resample.html#vips-resize
-func vipsResizeWithVScale(in *C.VipsImage, scale, vscale float64, kernel Kernel) (*C.VipsImage, error) {
-	incOpCounter("resize")
-	var out *C.VipsImage
-
-	if err := C.resize_image(in, &out, C.double(scale), C.gdouble(vscale), C.int(kernel)); err != 0 {
+	if err := C.resize_image(in, &out, C.double(hscale), C.double(vscale), C.int(kernel)); err != 0 {
 		return nil, handleImageError(out)
 	}