fix(#106): allow custom area extraction without x/y axis

resize.go

@@ -242,7 +242,7 @@ func extractOrEmbedImage(image *C.VipsImage, o Options) (*C.VipsImage, error) {
 		left, top := (o.Width-inWidth)/2, (o.Height-inHeight)/2
 		image, err = vipsEmbed(image, left, top, o.Width, o.Height, o.Extend, o.Background)
 		break
-	case o.Top != 0 || o.Left != 0:
+	case o.Top > 0 || o.Left > 0 || o.AreaWidth > 0 || o.AreaHeight > 0:
 		if o.AreaWidth == 0 {
 			o.AreaHeight = o.Width
 		}

resize_test.go

@@ -284,6 +284,40 @@ func TestSharpen(t *testing.T) {
 	Write("fixtures/test_sharpen.jpg", newImg)
 }
 
+func TestExtractWithDefaultAxis(t *testing.T) {
+	options := Options{AreaWidth: 200, AreaHeight: 200}
+	buf, _ := Read("fixtures/test.jpg")
+
+	newImg, err := Resize(buf, options)
+	if err != nil {
+		t.Errorf("Resize(imgData, %#v) error: %#v", options, err)
+	}
+
+	size, _ := Size(newImg)
+	if size.Height != options.AreaHeight || size.Width != options.AreaWidth {
+		t.Fatalf("Invalid image size: %dx%d", size.Width, size.Height)
+	}
+
+	Write("fixtures/test_extract_defaults.jpg", newImg)
+}
+
+func TestExtractCustomAxis(t *testing.T) {
+	options := Options{Top: 100, Left: 100, AreaWidth: 200, AreaHeight: 200}
+	buf, _ := Read("fixtures/test.jpg")
+
+	newImg, err := Resize(buf, options)
+	if err != nil {
+		t.Errorf("Resize(imgData, %#v) error: %#v", options, err)
+	}
+
+	size, _ := Size(newImg)
+	if size.Height != options.AreaHeight || size.Width != options.AreaWidth {
+		t.Fatalf("Invalid image size: %dx%d", size.Width, size.Height)
+	}
+
+	Write("fixtures/test_extract_custom_axis.jpg", newImg)
+}
+
 func TestConvert(t *testing.T) {
 	width, height := 300, 240
 	formats := [3]ImageType{PNG, WEBP, JPEG}