clip_test.go

     1  // Copyright 2011 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package draw
     6  
     7  import (
     8  	"image"
     9  	"testing"
    10  )
    11  
    12  type clipTest struct {
    13  	desc          string
    14  	r, dr, sr, mr image.Rectangle
    15  	sp, mp        image.Point
    16  	nilMask       bool
    17  	r0            image.Rectangle
    18  	sp0, mp0      image.Point
    19  }
    20  
    21  var clipTests = []clipTest{
    22  	// The following tests all have a nil mask.
    23  	{
    24  		"basic",
    25  		image.Rect(0, 0, 100, 100),
    26  		image.Rect(0, 0, 100, 100),
    27  		image.Rect(0, 0, 100, 100),
    28  		image.Rectangle{},
    29  		image.Point{},
    30  		image.Point{},
    31  		true,
    32  		image.Rect(0, 0, 100, 100),
    33  		image.Point{},
    34  		image.Point{},
    35  	},
    36  	{
    37  		"clip dr",
    38  		image.Rect(0, 0, 100, 100),
    39  		image.Rect(40, 40, 60, 60),
    40  		image.Rect(0, 0, 100, 100),
    41  		image.Rectangle{},
    42  		image.Point{},
    43  		image.Point{},
    44  		true,
    45  		image.Rect(40, 40, 60, 60),
    46  		image.Pt(40, 40),
    47  		image.Point{},
    48  	},
    49  	{
    50  		"clip sr",
    51  		image.Rect(0, 0, 100, 100),
    52  		image.Rect(0, 0, 100, 100),
    53  		image.Rect(20, 20, 80, 80),
    54  		image.Rectangle{},
    55  		image.Point{},
    56  		image.Point{},
    57  		true,
    58  		image.Rect(20, 20, 80, 80),
    59  		image.Pt(20, 20),
    60  		image.Point{},
    61  	},
    62  	{
    63  		"clip dr and sr",
    64  		image.Rect(0, 0, 100, 100),
    65  		image.Rect(0, 0, 50, 100),
    66  		image.Rect(20, 20, 80, 80),
    67  		image.Rectangle{},
    68  		image.Point{},
    69  		image.Point{},
    70  		true,
    71  		image.Rect(20, 20, 50, 80),
    72  		image.Pt(20, 20),
    73  		image.Point{},
    74  	},
    75  	{
    76  		"clip dr and sr, sp outside sr (top-left)",
    77  		image.Rect(0, 0, 100, 100),
    78  		image.Rect(0, 0, 50, 100),
    79  		image.Rect(20, 20, 80, 80),
    80  		image.Rectangle{},
    81  		image.Pt(15, 8),
    82  		image.Point{},
    83  		true,
    84  		image.Rect(5, 12, 50, 72),
    85  		image.Pt(20, 20),
    86  		image.Point{},
    87  	},
    88  	{
    89  		"clip dr and sr, sp outside sr (middle-left)",
    90  		image.Rect(0, 0, 100, 100),
    91  		image.Rect(0, 0, 50, 100),
    92  		image.Rect(20, 20, 80, 80),
    93  		image.Rectangle{},
    94  		image.Pt(15, 66),
    95  		image.Point{},
    96  		true,
    97  		image.Rect(5, 0, 50, 14),
    98  		image.Pt(20, 66),
    99  		image.Point{},
   100  	},
   101  	{
   102  		"clip dr and sr, sp outside sr (bottom-left)",
   103  		image.Rect(0, 0, 100, 100),
   104  		image.Rect(0, 0, 50, 100),
   105  		image.Rect(20, 20, 80, 80),
   106  		image.Rectangle{},
   107  		image.Pt(15, 91),
   108  		image.Point{},
   109  		true,
   110  		image.Rectangle{},
   111  		image.Pt(15, 91),
   112  		image.Point{},
   113  	},
   114  	{
   115  		"clip dr and sr, sp inside sr",
   116  		image.Rect(0, 0, 100, 100),
   117  		image.Rect(0, 0, 50, 100),
   118  		image.Rect(20, 20, 80, 80),
   119  		image.Rectangle{},
   120  		image.Pt(44, 33),
   121  		image.Point{},
   122  		true,
   123  		image.Rect(0, 0, 36, 47),
   124  		image.Pt(44, 33),
   125  		image.Point{},
   126  	},
   127  
   128  	// The following tests all have a non-nil mask.
   129  	{
   130  		"basic mask",
   131  		image.Rect(0, 0, 80, 80),
   132  		image.Rect(20, 0, 100, 80),
   133  		image.Rect(0, 0, 50, 49),
   134  		image.Rect(0, 0, 46, 47),
   135  		image.Point{},
   136  		image.Point{},
   137  		false,
   138  		image.Rect(20, 0, 46, 47),
   139  		image.Pt(20, 0),
   140  		image.Pt(20, 0),
   141  	},
   142  	{
   143  		"clip sr and mr",
   144  		image.Rect(0, 0, 100, 100),
   145  		image.Rect(0, 0, 100, 100),
   146  		image.Rect(23, 23, 55, 86),
   147  		image.Rect(44, 44, 87, 58),
   148  		image.Pt(10, 10),
   149  		image.Pt(11, 11),
   150  		false,
   151  		image.Rect(33, 33, 45, 47),
   152  		image.Pt(43, 43),
   153  		image.Pt(44, 44),
   154  	},
   155  }
   156  
   157  func TestClip(t *testing.T) {
   158  	dst0 := image.NewRGBA(image.Rect(0, 0, 100, 100))
   159  	src0 := image.NewRGBA(image.Rect(0, 0, 100, 100))
   160  	mask0 := image.NewRGBA(image.Rect(0, 0, 100, 100))
   161  	for _, c := range clipTests {
   162  		dst := dst0.SubImage(c.dr).(*image.RGBA)
   163  		src := src0.SubImage(c.sr).(*image.RGBA)
   164  		r, sp, mp := c.r, c.sp, c.mp
   165  		if c.nilMask {
   166  			clip(dst, &r, src, &sp, nil, nil)
   167  		} else {
   168  			clip(dst, &r, src, &sp, mask0.SubImage(c.mr), &mp)
   169  		}
   170  
   171  		// Check that the actual results equal the expected results.
   172  		if !c.r0.Eq(r) {
   173  			t.Errorf("%s: clip rectangle want %v got %v", c.desc, c.r0, r)
   174  			continue
   175  		}
   176  		if !c.sp0.Eq(sp) {
   177  			t.Errorf("%s: sp want %v got %v", c.desc, c.sp0, sp)
   178  			continue
   179  		}
   180  		if !c.nilMask {
   181  			if !c.mp0.Eq(mp) {
   182  				t.Errorf("%s: mp want %v got %v", c.desc, c.mp0, mp)
   183  				continue
   184  			}
   185  		}
   186  
   187  		// Check that the clipped rectangle is contained by the dst / src / mask
   188  		// rectangles, in their respective coordinate spaces.
   189  		if !r.In(c.dr) {
   190  			t.Errorf("%s: c.dr %v does not contain r %v", c.desc, c.dr, r)
   191  		}
   192  		// sr is r translated into src's coordinate space.
   193  		sr := r.Add(c.sp.Sub(c.dr.Min))
   194  		if !sr.In(c.sr) {
   195  			t.Errorf("%s: c.sr %v does not contain sr %v", c.desc, c.sr, sr)
   196  		}
   197  		if !c.nilMask {
   198  			// mr is r translated into mask's coordinate space.
   199  			mr := r.Add(c.mp.Sub(c.dr.Min))
   200  			if !mr.In(c.mr) {
   201  				t.Errorf("%s: c.mr %v does not contain mr %v", c.desc, c.mr, mr)
   202  			}
   203  		}
   204  	}
   205  }
   206
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