stdlib_test.go

Documentation: golang.org/x/image/draw

     1  // Copyright 2015 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  	"bytes"
     9  	"image"
    10  	"image/color"
    11  	"testing"
    12  )
    13  
    14  // TestFastPaths tests that the fast path implementations produce identical
    15  // results to the generic implementation.
    16  func TestFastPaths(t *testing.T) {
    17  	drs := []image.Rectangle{
    18  		image.Rect(0, 0, 10, 10),   // The dst bounds.
    19  		image.Rect(3, 4, 8, 6),     // A strict subset of the dst bounds.
    20  		image.Rect(-3, -5, 2, 4),   // Partial out-of-bounds #0.
    21  		image.Rect(4, -2, 6, 12),   // Partial out-of-bounds #1.
    22  		image.Rect(12, 14, 23, 45), // Complete out-of-bounds.
    23  		image.Rect(5, 5, 5, 5),     // Empty.
    24  	}
    25  	srs := []image.Rectangle{
    26  		image.Rect(0, 0, 12, 9),    // The src bounds.
    27  		image.Rect(2, 2, 10, 8),    // A strict subset of the src bounds.
    28  		image.Rect(10, 5, 20, 20),  // Partial out-of-bounds #0.
    29  		image.Rect(-40, 0, 40, 8),  // Partial out-of-bounds #1.
    30  		image.Rect(-8, -8, -4, -4), // Complete out-of-bounds.
    31  		image.Rect(5, 5, 5, 5),     // Empty.
    32  	}
    33  	srcfs := []func(image.Rectangle) (image.Image, error){
    34  		srcGray,
    35  		srcNRGBA,
    36  		srcRGBA,
    37  		srcUnif,
    38  		srcYCbCr,
    39  	}
    40  	var srcs []image.Image
    41  	for _, srcf := range srcfs {
    42  		src, err := srcf(srs[0])
    43  		if err != nil {
    44  			t.Fatal(err)
    45  		}
    46  		srcs = append(srcs, src)
    47  	}
    48  	qs := []Interpolator{
    49  		NearestNeighbor,
    50  		ApproxBiLinear,
    51  		CatmullRom,
    52  	}
    53  	ops := []Op{
    54  		Over,
    55  		Src,
    56  	}
    57  	blue := image.NewUniform(color.RGBA{0x11, 0x22, 0x44, 0x7f})
    58  
    59  	for _, dr := range drs {
    60  		for _, src := range srcs {
    61  			for _, sr := range srs {
    62  				for _, transform := range []bool{false, true} {
    63  					for _, q := range qs {
    64  						for _, op := range ops {
    65  							dst0 := image.NewRGBA(drs[0])
    66  							dst1 := image.NewRGBA(drs[0])
    67  							Draw(dst0, dst0.Bounds(), blue, image.Point{}, Src)
    68  							Draw(dstWrapper{dst1}, dst1.Bounds(), srcWrapper{blue}, image.Point{}, Src)
    69  
    70  							if transform {
    71  								m := transformMatrix(3.75, 2, 1)
    72  								q.Transform(dst0, m, src, sr, op, nil)
    73  								q.Transform(dstWrapper{dst1}, m, srcWrapper{src}, sr, op, nil)
    74  							} else {
    75  								q.Scale(dst0, dr, src, sr, op, nil)
    76  								q.Scale(dstWrapper{dst1}, dr, srcWrapper{src}, sr, op, nil)
    77  							}
    78  
    79  							if !bytes.Equal(dst0.Pix, dst1.Pix) {
    80  								t.Errorf("pix differ for dr=%v, src=%T, sr=%v, transform=%t, q=%T",
    81  									dr, src, sr, transform, q)
    82  							}
    83  						}
    84  					}
    85  				}
    86  			}
    87  		}
    88  	}
    89  }
    90
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