Improved images.Crop() and implemented testing

images/manipulation.go

@@ -1,20 +1,30 @@
 package images
 
 import (
+	"fmt"
 	"image"
 
 	"github.com/nfnt/resize"
 	"github.com/oliamb/cutter"
 )
 
-func ResizeSquare(size uint, img image.Image) image.Image {
-	return resize.Resize(size, 0, img, resize.Bilinear)
+func Resize(width, height uint, img image.Image) image.Image {
+	return resize.Resize(width, height, img, resize.Bilinear)
 }
 
-func CropSquare(img image.Image, size int, anchor image.Point) (image.Image, error) {
+func Crop(img image.Image, rect image.Rectangle) (image.Image, error) {
+
+	if img.Bounds().Max.X < rect.Max.X || img.Bounds().Max.Y < rect.Max.Y{
+		return nil, fmt.Errorf(
+			"crop dimensions out of bounds of image, image width '%dpx' & height '%dpx'; crop bottom right coordinate at X '%dpx' Y '%dpx'",
+			img.Bounds().Max.X, img.Bounds().Max.Y,
+			rect.Max.X, rect.Max.Y,
+		)
+	}
+
 	return cutter.Crop(img, cutter.Config{
-		Width:  size,
-		Height: size,
-		Anchor: anchor,
+		Width:  rect.Dx(),
+		Height: rect.Dy(),
+		Anchor: rect.Min,
 	})
 }

images/manipulation_test.go

@@ -0,0 +1,99 @@
+package images
+
+import (
+	"bytes"
+	"errors"
+	"github.com/stretchr/testify/require"
+	"image"
+	"testing"
+)
+
+func TestResize(t *testing.T) {
+
+}
+
+func TestCrop(t *testing.T) {
+	type params struct{
+		Rectangle image.Rectangle
+		OutputBound image.Rectangle
+		OutputSize int
+		CropError error
+	}
+
+	topLeftSquare := image.Rectangle{
+		Min: image.Point{X: 0, Y: 0},
+		Max: image.Point{X: 80, Y: 80},
+	}
+	offsetSquare := image.Rectangle{
+		Min: image.Point{X: 80,	Y: 80},
+		Max: image.Point{X: 160, Y: 160},
+	}
+	outOfBoundsSquare := image.Rectangle{
+		Min: image.Point{X: 0, Y: 0},
+		Max: image.Point{X: 1000000, Y: 1000000},
+	}
+	rect := image.Rectangle{}
+	options := &Details{
+		Quality: 70,
+	}
+
+	cs := []struct{
+		FileName string
+		Params   []params
+	}{
+		{
+			"elephant.jpg",
+			[]params{
+				{topLeftSquare, topLeftSquare, 1447, nil},
+				{offsetSquare, rect, 0, errors.New("crop dimensions out of bounds of image, image width '80px' & height '80px'; crop bottom right coordinate at X '160px' Y '160px'")},
+				{outOfBoundsSquare, rect, 0, errors.New("crop dimensions out of bounds of image, image width '80px' & height '80px'; crop bottom right coordinate at X '1000000px' Y '1000000px'")},
+			},
+		},
+		{
+			"rose.webp",
+			[]params{
+				{topLeftSquare, topLeftSquare, 1183, nil},
+				{offsetSquare, offsetSquare, 1251, nil},
+				{outOfBoundsSquare, rect, 0, errors.New("crop dimensions out of bounds of image, image width '400px' & height '301px'; crop bottom right coordinate at X '1000000px' Y '1000000px'")},
+			},
+		},
+		{
+			"spin.gif",
+			[]params{
+				{topLeftSquare, topLeftSquare, 693, nil},
+				{offsetSquare, offsetSquare, 1339, nil},
+				{outOfBoundsSquare, rect, 0, errors.New("crop dimensions out of bounds of image, image width '256px' & height '256px'; crop bottom right coordinate at X '1000000px' Y '1000000px'")},
+			},
+		},
+		{
+			"status.png",
+			[]params{
+				{topLeftSquare, topLeftSquare, 1027, nil},
+				{offsetSquare, offsetSquare, 1157, nil},
+				{outOfBoundsSquare, rect, 0, errors.New("crop dimensions out of bounds of image, image width '256px' & height '256px'; crop bottom right coordinate at X '1000000px' Y '1000000px'")},
+			},
+		},
+	}
+
+	for _, c := range cs {
+		img, err := Get(path + c.FileName)
+		require.NoError(t, err)
+
+		for _, p := range c.Params {
+			cImg, err := Crop(img, p.Rectangle)
+			if p.CropError != nil {
+				require.EqualError(t, err, p.CropError.Error())
+				continue
+			} else {
+				require.NoError(t, err)
+			}
+			require.Exactly(t, p.OutputBound.Dx(), cImg.Bounds().Dx(), c.FileName)
+			require.Exactly(t, p.OutputBound.Dy(), cImg.Bounds().Dy(), c.FileName)
+
+			bb := bytes.NewBuffer([]byte{})
+			err = Render(bb, cImg, options)
+			require.NoError(t, err)
+			require.Exactly(t, p.OutputSize, bb.Len())
+		}
+	}
+}