...
Run Format

Source file src/image/ycbcr_test.go

Documentation: image

  // Copyright 2012 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  package image
  
  import (
  	"image/color"
  	"testing"
  )
  
  func TestYCbCr(t *testing.T) {
  	rects := []Rectangle{
  		Rect(0, 0, 16, 16),
  		Rect(1, 0, 16, 16),
  		Rect(0, 1, 16, 16),
  		Rect(1, 1, 16, 16),
  		Rect(1, 1, 15, 16),
  		Rect(1, 1, 16, 15),
  		Rect(1, 1, 15, 15),
  		Rect(2, 3, 14, 15),
  		Rect(7, 0, 7, 16),
  		Rect(0, 8, 16, 8),
  		Rect(0, 0, 10, 11),
  		Rect(5, 6, 16, 16),
  		Rect(7, 7, 8, 8),
  		Rect(7, 8, 8, 9),
  		Rect(8, 7, 9, 8),
  		Rect(8, 8, 9, 9),
  		Rect(7, 7, 17, 17),
  		Rect(8, 8, 17, 17),
  		Rect(9, 9, 17, 17),
  		Rect(10, 10, 17, 17),
  	}
  	subsampleRatios := []YCbCrSubsampleRatio{
  		YCbCrSubsampleRatio444,
  		YCbCrSubsampleRatio422,
  		YCbCrSubsampleRatio420,
  		YCbCrSubsampleRatio440,
  		YCbCrSubsampleRatio411,
  		YCbCrSubsampleRatio410,
  	}
  	deltas := []Point{
  		Pt(0, 0),
  		Pt(1000, 1001),
  		Pt(5001, -400),
  		Pt(-701, -801),
  	}
  	for _, r := range rects {
  		for _, subsampleRatio := range subsampleRatios {
  			for _, delta := range deltas {
  				testYCbCr(t, r, subsampleRatio, delta)
  			}
  		}
  		if testing.Short() {
  			break
  		}
  	}
  }
  
  func testYCbCr(t *testing.T, r Rectangle, subsampleRatio YCbCrSubsampleRatio, delta Point) {
  	// Create a YCbCr image m, whose bounds are r translated by (delta.X, delta.Y).
  	r1 := r.Add(delta)
  	m := NewYCbCr(r1, subsampleRatio)
  
  	// Test that the image buffer is reasonably small even if (delta.X, delta.Y) is far from the origin.
  	if len(m.Y) > 100*100 {
  		t.Errorf("r=%v, subsampleRatio=%v, delta=%v: image buffer is too large",
  			r, subsampleRatio, delta)
  		return
  	}
  
  	// Initialize m's pixels. For 422 and 420 subsampling, some of the Cb and Cr elements
  	// will be set multiple times. That's OK. We just want to avoid a uniform image.
  	for y := r1.Min.Y; y < r1.Max.Y; y++ {
  		for x := r1.Min.X; x < r1.Max.X; x++ {
  			yi := m.YOffset(x, y)
  			ci := m.COffset(x, y)
  			m.Y[yi] = uint8(16*y + x)
  			m.Cb[ci] = uint8(y + 16*x)
  			m.Cr[ci] = uint8(y + 16*x)
  		}
  	}
  
  	// Make various sub-images of m.
  	for y0 := delta.Y + 3; y0 < delta.Y+7; y0++ {
  		for y1 := delta.Y + 8; y1 < delta.Y+13; y1++ {
  			for x0 := delta.X + 3; x0 < delta.X+7; x0++ {
  				for x1 := delta.X + 8; x1 < delta.X+13; x1++ {
  					subRect := Rect(x0, y0, x1, y1)
  					sub := m.SubImage(subRect).(*YCbCr)
  
  					// For each point in the sub-image's bounds, check that m.At(x, y) equals sub.At(x, y).
  					for y := sub.Rect.Min.Y; y < sub.Rect.Max.Y; y++ {
  						for x := sub.Rect.Min.X; x < sub.Rect.Max.X; x++ {
  							color0 := m.At(x, y).(color.YCbCr)
  							color1 := sub.At(x, y).(color.YCbCr)
  							if color0 != color1 {
  								t.Errorf("r=%v, subsampleRatio=%v, delta=%v, x=%d, y=%d, color0=%v, color1=%v",
  									r, subsampleRatio, delta, x, y, color0, color1)
  								return
  							}
  						}
  					}
  				}
  			}
  		}
  	}
  }
  
  func TestYCbCrSlicesDontOverlap(t *testing.T) {
  	m := NewYCbCr(Rect(0, 0, 8, 8), YCbCrSubsampleRatio420)
  	names := []string{"Y", "Cb", "Cr"}
  	slices := [][]byte{
  		m.Y[:cap(m.Y)],
  		m.Cb[:cap(m.Cb)],
  		m.Cr[:cap(m.Cr)],
  	}
  	for i, slice := range slices {
  		want := uint8(10 + i)
  		for j := range slice {
  			slice[j] = want
  		}
  	}
  	for i, slice := range slices {
  		want := uint8(10 + i)
  		for j, got := range slice {
  			if got != want {
  				t.Fatalf("m.%s[%d]: got %d, want %d", names[i], j, got, want)
  			}
  		}
  	}
  }
  

View as plain text