imagefn - flip_test.go

     1  package imagefn
     2  
     3  import (
     4  	"image"
     5  	"image/color"
     6  	"testing"
     7  )
     8  
     9  func testImage(a, b image.Image) bool {
    10  	ab := a.Bounds()
    11  	bb := b.Bounds()
    12  	dx := ab.Dx()
    13  	dy := ab.Dy()
    14  	if dx != bb.Dx() || dy != bb.Dy() {
    15  		return false
    16  	}
    17  	for j := 0; j < dy; j++ {
    18  		for i := 0; i < dx; i++ {
    19  			ar, ag, ab, aa := a.At(ab.Min.X+i, ab.Min.Y+j).RGBA()
    20  			br, bg, bb, ba := b.At(bb.Min.X+i, bb.Min.Y+j).RGBA()
    21  			if ar != br || ag != bg || ab != bb || aa != ba {
    22  				return false
    23  			}
    24  		}
    25  	}
    26  	return true
    27  }
    28  
    29  func newGray(w, h int, pix ...uint8) *image.Gray {
    30  	g := image.NewGray(image.Rect(0, 0, w, h))
    31  Loop:
    32  	for y := 0; y < h; y++ {
    33  		for x := 0; x < w; x++ {
    34  			g.SetGray(x, y, color.Gray{pix[0]})
    35  			pix = pix[1:]
    36  			if len(pix) == 0 {
    37  				break Loop
    38  			}
    39  		}
    40  	}
    41  	return g
    42  }
    43  
    44  func TestFlipX(t *testing.T) {
    45  	for n, test := range [...]struct {
    46  		In, Out  *image.Gray
    47  		SubImage image.Rectangle
    48  	}{
    49  		{
    50  			newGray(1, 1, 1),
    51  			newGray(1, 1, 1),
    52  			image.Rect(0, 0, 1, 1),
    53  		},
    54  		{
    55  			newGray(1, 2, 0, 1),
    56  			newGray(1, 2, 0, 1),
    57  			image.Rect(0, 1, 1, 2),
    58  		},
    59  		{
    60  			newGray(2, 1, 0, 1),
    61  			newGray(2, 1, 1, 0),
    62  			image.Rect(0, 0, 1, 1),
    63  		},
    64  		{
    65  			newGray(3, 3, 0, 1, 2, 3, 4, 5, 6, 7, 8),
    66  			newGray(3, 3, 2, 1, 0, 5, 4, 3, 8, 7, 6),
    67  			image.Rect(1, 1, 3, 3),
    68  		},
    69  	} {
    70  		fx := FlipX(test.In)
    71  		if !testImage(fx, test.Out) {
    72  			t.Errorf("test %d: images do not match", n+1)
    73  		}
    74  		if !testImage(SubImage(fx, test.SubImage), test.Out.SubImage(test.SubImage)) {
    75  			t.Errorf("test %d: subimages do not match", n+1)
    76  		}
    77  	}
    78  }
    79  
    80  func TestFlipY(t *testing.T) {
    81  	for n, test := range []struct {
    82  		In, Out  *image.Gray
    83  		SubImage image.Rectangle
    84  	}{
    85  		{
    86  			newGray(1, 1, 1),
    87  			newGray(1, 1, 1),
    88  			image.Rect(0, 0, 1, 1),
    89  		},
    90  		{
    91  			newGray(2, 1, 0, 1),
    92  			newGray(2, 1, 0, 1),
    93  			image.Rect(0, 1, 2, 1),
    94  		},
    95  		{
    96  			newGray(1, 2, 0, 1),
    97  			newGray(1, 2, 1, 0),
    98  			image.Rect(0, 0, 1, 1),
    99  		},
   100  		{
   101  			newGray(3, 3, 0, 1, 2, 3, 4, 5, 6, 7, 8),
   102  			newGray(3, 3, 6, 7, 8, 3, 4, 5, 0, 1, 2),
   103  			image.Rect(1, 1, 3, 3),
   104  		},
   105  	} {
   106  		fy := FlipY(test.In)
   107  		if !testImage(fy, test.Out) {
   108  			t.Errorf("test %d: images do not match", n+1)
   109  		}
   110  		if !testImage(SubImage(fy, test.SubImage), test.Out.SubImage(test.SubImage)) {
   111  			t.Errorf("test %d: subimages do not match", n+1)
   112  		}
   113  	}
   114  }