test: added new test cases

carver_test.go

@@ -0,0 +1,204 @@
+package caire
+
+import (
+	"image"
+	"image/color"
+	"image/draw"
+	"testing"
+)
+
+var p *Processor
+
+func init() {
+	p = &Processor{
+		NewWidth:       ImgWidth,
+		NewHeight:      ImgHeight,
+		BlurRadius:     1,
+		SobelThreshold: 4,
+		Percentage:     false,
+		Square:         false,
+		Debug:          false,
+	}
+}
+
+func TestCarver_EnergySeamShouldNotBeDetected(t *testing.T) {
+	var seams [][]Seam
+	var totalEnergySeams int
+
+	img := image.NewNRGBA(image.Rect(0, 0, ImgWidth, ImgHeight))
+	dx, dy := img.Bounds().Dx(), img.Bounds().Dy()
+
+	var c = NewCarver(dx, dy)
+	for x := 0; x < ImgWidth; x++ {
+		width, height := img.Bounds().Max.X, img.Bounds().Max.Y
+		c = NewCarver(width, height)
+		c.ComputeSeams(img, p)
+		les := c.FindLowestEnergySeams()
+		seams = append(seams, les)
+	}
+
+	for i := 0; i < len(seams); i++ {
+		for s := 0; s < len(seams[i]); s++ {
+			totalEnergySeams += seams[i][s].X
+		}
+	}
+	if totalEnergySeams != 0 {
+		t.Errorf("Energy seam shouldn't been detected")
+	}
+}
+
+func TestCarver_DetectHorizontalEnergySeam(t *testing.T) {
+	var seams [][]Seam
+	var totalEnergySeams int
+
+	img := image.NewNRGBA(image.Rect(0, 0, ImgWidth, ImgHeight))
+	draw.Draw(img, img.Bounds(), &image.Uniform{image.White}, image.ZP, draw.Src)
+
+	// Replace the pixel colors in a single row from 0xff to 0xdd. 5 is an arbitrary value.
+	// The seam detector should recognize that line as being of low energy density
+	// and should perform the seam computation process.
+	// This way we'll make sure, that the seam detector correctly detects one and only one line.
+	dx, dy := img.Bounds().Dx(), img.Bounds().Dy()
+	for x := 0; x < dx; x++ {
+		img.Pix[(5*dx+x)*4+0] = 0xdd
+		img.Pix[(5*dx+x)*4+1] = 0xdd
+		img.Pix[(5*dx+x)*4+2] = 0xdd
+		img.Pix[(5*dx+x)*4+3] = 0xdd
+	}
+
+	var c = NewCarver(dx, dy)
+	for x := 0; x < ImgWidth; x++ {
+		width, height := img.Bounds().Max.X, img.Bounds().Max.Y
+		c = NewCarver(width, height)
+		c.ComputeSeams(img, p)
+		les := c.FindLowestEnergySeams()
+		seams = append(seams, les)
+	}
+
+	for i := 0; i < len(seams); i++ {
+		for s := 0; s < len(seams[i]); s++ {
+			totalEnergySeams += seams[i][s].X
+		}
+	}
+	if totalEnergySeams == 0 {
+		t.Errorf("The seam detector should have detected a horizontal energy seam")
+	}
+}
+
+func TestCarver_DetectVerticalEnergySeam(t *testing.T) {
+	var seams [][]Seam
+	var totalEnergySeams int
+
+	img := image.NewNRGBA(image.Rect(0, 0, ImgWidth, ImgHeight))
+	draw.Draw(img, img.Bounds(), &image.Uniform{image.White}, image.ZP, draw.Src)
+
+	// Replace the pixel colors in a single column from 0xff to 0xdd. 5 is an arbitrary value.
+	// The seam detector should recognize that line as being of low energy density
+	// and should perform the seam computation process.
+	// This way we'll make sure, that the seam detector correctly detects one and only one line.
+	dx, dy := img.Bounds().Dx(), img.Bounds().Dy()
+	for y := 0; y < dy; y++ {
+		img.Pix[5*4+(dx*y)*4+0] = 0xdd
+		img.Pix[5*4+(dx*y)*4+1] = 0xdd
+		img.Pix[5*4+(dx*y)*4+2] = 0xdd
+		img.Pix[5*4+(dx*y)*4+3] = 0xff
+	}
+
+	var c = NewCarver(dx, dy)
+	img = c.RotateImage90(img)
+	for x := 0; x < ImgHeight; x++ {
+		width, height := img.Bounds().Max.X, img.Bounds().Max.Y
+		c = NewCarver(width, height)
+		c.ComputeSeams(img, p)
+		les := c.FindLowestEnergySeams()
+		seams = append(seams, les)
+	}
+	img = c.RotateImage270(img)
+
+	for i := 0; i < len(seams); i++ {
+		for s := 0; s < len(seams[i]); s++ {
+			totalEnergySeams += seams[i][s].X
+		}
+	}
+	if totalEnergySeams == 0 {
+		t.Errorf("The seam detector should have detected a vertical energy seam")
+	}
+}
+
+func TestCarver_RemoveSeam(t *testing.T) {
+	img := image.NewNRGBA(image.Rect(0, 0, ImgWidth, ImgHeight))
+	bounds := img.Bounds()
+
+	// We choose to fill up the background with an uniform white color
+	// and afterwards we replace the colors in a single row with lower intensity ones.
+	draw.Draw(img, bounds, &image.Uniform{image.White}, image.ZP, draw.Src)
+	origImg := img
+
+	dx, dy := img.Bounds().Dx(), img.Bounds().Dy()
+	// Replace the pixels in row 5 with lower intensity colors.
+	for x := 0; x < dx; x++ {
+		img.Set(x, 5, color.RGBA{R: 0xdd, G: 0xdd, B: 0xdd, A: 0xff})
+	}
+
+	c := NewCarver(dx, dy)
+	c.ComputeSeams(img, p)
+	seams := c.FindLowestEnergySeams()
+	img = c.RemoveSeam(img, seams, false)
+
+	isEq := true
+	// The test should pass if the detector correctly finds the row wich pixel values are of lower intensity.
+	for x := 0; x < dx; x++ {
+		for y := 0; y < dy; y++ {
+			// In case the seam detector correctly recognize the modified line as of low importance
+			// it should remove it, which means the new image width should be 1px less then the original image.
+			r0, g0, b0, _ := origImg.At(x, y).RGBA()
+			r1, g1, b1, _ := img.At(x, y).RGBA()
+
+			if r0>>8 != r1>>8 && g0>>8 != g1>>8 && b0>>8 != b1>>8 {
+				isEq = false
+			}
+		}
+	}
+	if isEq {
+		t.Errorf("Seam should have been removed")
+	}
+}
+
+func TestCarver_AddSeam(t *testing.T) {
+	img := image.NewNRGBA(image.Rect(0, 0, ImgWidth, ImgHeight))
+	bounds := img.Bounds()
+
+	// We choose to fill up the background with an uniform white color
+	// Afterwards we'll replace the colors in a single row with lower intensity ones.
+	draw.Draw(img, bounds, &image.Uniform{image.White}, image.ZP, draw.Src)
+	origImg := img
+
+	dx, dy := img.Bounds().Dx(), img.Bounds().Dy()
+	// Replace the pixels in row 5 with lower intensity colors.
+	for x := 0; x < dx; x++ {
+		img.Set(x, 5, color.RGBA{R: 0xdd, G: 0xdd, B: 0xdd, A: 0xff})
+	}
+
+	c := NewCarver(dx, dy)
+	c.ComputeSeams(img, p)
+	seams := c.FindLowestEnergySeams()
+	img = c.AddSeam(img, seams, false)
+
+	dx, dy = img.Bounds().Dx(), img.Bounds().Dy()
+
+	isEq := true
+	// The test should pass if the detector correctly finds the row wich has lower intensity colors.
+	for x := 0; x < dx; x++ {
+		for y := 0; y < dy; y++ {
+			r0, g0, b0, _ := origImg.At(x, y).RGBA()
+			r1, g1, b1, _ := img.At(x, y).RGBA()
+
+			if r0>>8 != r1>>8 && g0>>8 != g1>>8 && b0>>8 != b1>>8 {
+				isEq = false
+			}
+		}
+	}
+	if isEq {
+		t.Errorf("Seam should have been added")
+	}
+}

grayscale_test.go

@@ -6,10 +6,12 @@ import (
 	"testing"
 )
 
-const ImgWidth = 10
-const ImgHeight = 10
+const (
+	ImgWidth  = 10
+	ImgHeight = 10
+)
 
-func TestGrayscale(t *testing.T) {
+func TestImage_GrayscaleMode(t *testing.T) {
 	img := image.NewRGBA(image.Rect(0, 0, ImgWidth, ImgHeight))
 	for i := 0; i < img.Bounds().Dx(); i++ {
 		for j := 0; j < img.Bounds().Dy(); j++ {

process.go

@@ -417,7 +417,7 @@ func (p *Processor) Process(r io.Reader, w io.Writer) error {
 	if err != nil {
 		return err
 	}
-	img := imgToNRGBA(src)
+	img := p.imgToNRGBA(src)
 
 	switch w.(type) {
 	case *os.File:
@@ -491,7 +491,7 @@ func (p *Processor) enlarge(c *Carver, img *image.NRGBA) (*image.NRGBA, error) {
 }
 
 // imgToNRGBA converts any image type to *image.NRGBA with min-point at (0, 0).
-func imgToNRGBA(img image.Image) *image.NRGBA {
+func (p *Processor) imgToNRGBA(img image.Image) *image.NRGBA {
 	srcBounds := img.Bounds()
 	if srcBounds.Min.X == 0 && srcBounds.Min.Y == 0 {
 		if src0, ok := img.(*image.NRGBA); ok {

process_test.go

@@ -5,25 +5,14 @@ import (
 	"testing"
 )
 
-func TestProcessor_Resize(t *testing.T) {
-	reduceImageH(t)
-	reduceImageV(t)
-}
-
-func reduceImageH(t *testing.T) {
+func TestResize_ReduceImageWidth(t *testing.T) {
 	img := image.NewNRGBA(image.Rect(0, 0, ImgWidth, ImgHeight))
 	var c = NewCarver(img.Bounds().Dx(), img.Bounds().Dy())
 	newWidth := ImgWidth / 2
-	p := &Processor{
-		BlurRadius:     2,
-		SobelThreshold: 10,
-		NewWidth:       newWidth,
-		NewHeight:      ImgHeight,
-		Percentage:     false,
-		Square:         false,
-		Debug:          false,
-	}
-	// Reduce image size horizontally
+
+	p.NewWidth = newWidth
+	p.NewHeight = ImgHeight
+
 	for x := 0; x < newWidth; x++ {
 		width, height := img.Bounds().Max.X, img.Bounds().Max.Y
 		c = NewCarver(width, height)
@@ -38,20 +27,14 @@ func reduceImageH(t *testing.T) {
 	}
 }
 
-func reduceImageV(t *testing.T) {
+func TestResize_ReduceImageHeight(t *testing.T) {
 	img := image.NewNRGBA(image.Rect(0, 0, ImgWidth, ImgHeight))
 	var c = NewCarver(img.Bounds().Dx(), img.Bounds().Dy())
 	newHeight := ImgHeight / 2
-	p := &Processor{
-		BlurRadius:     2,
-		SobelThreshold: 10,
-		NewWidth:       ImgWidth,
-		NewHeight:      newHeight,
-		Percentage:     false,
-		Square:         false,
-		Debug:          false,
-	}
-	// Reduce image size horizontally
+
+	p.NewWidth = ImgWidth
+	p.NewHeight = newHeight
+
 	img = c.RotateImage90(img)
 	for x := 0; x < newHeight; x++ {
 		width, height := img.Bounds().Max.X, img.Bounds().Max.Y
@@ -67,3 +50,51 @@ func reduceImageV(t *testing.T) {
 		t.Errorf("Resulted image height expected to be %v. Got %v", newHeight, imgHeight)
 	}
 }
+
+func TestResize_IncreaseImageWidth(t *testing.T) {
+	img := image.NewNRGBA(image.Rect(0, 0, ImgWidth, ImgHeight))
+	origImgWidth := img.Bounds().Dx()
+	var c = NewCarver(img.Bounds().Dx(), img.Bounds().Dy())
+	newWidth := ImgWidth * 2
+
+	p.NewWidth = newWidth
+	p.NewHeight = ImgHeight
+
+	for x := 0; x < newWidth; x++ {
+		width, height := img.Bounds().Max.X, img.Bounds().Max.Y
+		c = NewCarver(width, height)
+		c.ComputeSeams(img, p)
+		seams := c.FindLowestEnergySeams()
+		img = c.AddSeam(img, seams, p.Debug)
+	}
+	imgWidth := img.Bounds().Max.X - origImgWidth
+
+	if imgWidth != newWidth {
+		t.Errorf("Resulted image width expected to be %v. Got %v", newWidth, imgWidth)
+	}
+}
+
+func TestResize_IncreaseImageHeight(t *testing.T) {
+	img := image.NewNRGBA(image.Rect(0, 0, ImgWidth, ImgHeight))
+	origImgHeigth := img.Bounds().Dy()
+	var c = NewCarver(img.Bounds().Dx(), img.Bounds().Dy())
+	newHeight := ImgHeight * 2
+
+	p.NewWidth = ImgWidth
+	p.NewHeight = newHeight
+
+	img = c.RotateImage90(img)
+	for x := 0; x < newHeight; x++ {
+		width, height := img.Bounds().Max.X, img.Bounds().Max.Y
+		c = NewCarver(width, height)
+		c.ComputeSeams(img, p)
+		seams := c.FindLowestEnergySeams()
+		img = c.AddSeam(img, seams, p.Debug)
+	}
+	img = c.RotateImage270(img)
+	imgHeight := img.Bounds().Max.Y - origImgHeigth
+
+	if imgHeight != newHeight {
+		t.Errorf("Resulted image height expected to be %v. Got %v", newHeight, imgHeight)
+	}
+}