refactor: crop and tests

README.md

@@ -2,9 +2,9 @@
 
 Go library for blazing fast image processing based on [libvips](https://github.com/jcupitt/libvips) using C bindings. 
 
-**bimg** was focused on performance, resizing an image with libvips is typically 4x faster than using the quickest ImageMagick and GraphicsMagick settings.
+libvips is typically 4x faster than using the quickest ImageMagick and GraphicsMagick settings, and even 8x faster with JPEG format. It support JPEG, PNG, WEBP, TIFF and Magick image formats.
 
-**bimg** was heavily inspired in [sharp](https://github.com/lovell/sharp), a great node.js package for image processing build by [Lovell Fuller](https://github.com/lovell).
+bimg was heavily inspired in [sharp](https://github.com/lovell/sharp), a great node.js package for image processing build by [Lovell Fuller](https://github.com/lovell).
 
 `Work in progress`
 
@@ -29,6 +29,16 @@ curl -s https://raw.githubusercontent.com/lovell/sharp/master/preinstall.sh | su
 
 The [install script](https://github.com/lovell/sharp/blob/master/preinstall.sh) requires `curl` and `pkg-config`.
 
+## Image operations
+
+- Resize
+- Crop
+- Enlarge
+- Zoom
+- Extract
+- Image metadata
+- Image conversion to multiple formats
+
 ## API
 
 ```go

image.go

@@ -22,6 +22,15 @@ func (i *Image) Extract(top int, left int, width int, height int) ([]byte, error
 	return i.Process(options)
 }
 
+func (i *Image) Crop(width int, height int) ([]byte, error) {
+	options := Options{
+		Width:  width,
+		Height: height,
+		Crop:   true,
+	}
+	return i.Process(options)
+}
+
 func (i *Image) Rotate(a Angle) ([]byte, error) {
 	options := Options{Rotate: a}
 	return i.Process(options)

image_test.go

@@ -7,13 +7,31 @@ import (
 )
 
 func TestImageResize(t *testing.T) {
-	data, _ := os.Open("fixtures/test.jpg")
-	buf, err := ioutil.ReadAll(data)
+	image := readImage()
+	_, err := image.Resize(300, 240)
+	if err != nil {
+		t.Errorf("Cannot process the image: %#v", err)
+	}
+}
 
-	image := NewImage(buf)
+func TestImageCrop(t *testing.T) {
+	image := readImage()
+	_, err := image.Crop(300, 240)
+	if err != nil {
+		t.Errorf("Cannot process the image: %#v", err)
+	}
+}
 
-	buf, err = image.Resize(300, 240)
+func TestImageRotate(t *testing.T) {
+	image := readImage()
+	_, err := image.Rotate(D90)
 	if err != nil {
 		t.Errorf("Cannot process the image: %#v", err)
 	}
 }
+
+func readImage() *Image {
+	data, _ := os.Open("fixtures/test.jpg")
+	buf, _ := ioutil.ReadAll(data)
+	return NewImage(buf)
+}