Function TestGradient

paint/raster/raster_test.go:449–567

TestGradient tests a Dasher's ability to function as a filler, stroker, and dasher by invoking the corresponding anonymous structs

(t *testing.T)

// TestGradient tests a Dasher's ability to function
// as a filler, stroker, and dasher by invoking the corresponding anonymous structs
func TestGradient(t *testing.T) {
	var (
		wx, wy  = 512, 512
		img     = image.NewRGBA(image.Rect(0, 0, wx, wy))
		scanner = scan.NewScanner(scan.NewImgSpanner(img), wx, wy)
	)

	linear := gradient.NewLinear()
	linear.SetBox(math32.B2(50, 50, 150, 150)).
		AddStop(colors.Aquamarine, 0.3).
		AddStop(colors.Skyblue, 0.6).
		AddStop(colors.ApplyOpacity(colors.Darksalmon, 0.75), 1)

	radial := gradient.NewRadial()
	radial.SetBox(math32.B2(230, 230, 330, 330)).
		SetSpread(gradient.Reflect).
		AddStop(colors.Orchid, 0.3).
		AddStop(colors.Bisque, 0.6).
		AddStop(colors.ApplyOpacity(colors.Chartreuse, 0.4), 1)

	d := NewDasher(wx, wy, scanner)
	d.SetStroke(10*64, 4*64, RoundCap, nil, RoundGap, ArcClip, []float32{33, 12}, 0)
	// p is in the shape of a capital Q
	p := getPartPath()

	f := &d.Filler // This is the anon Filler in the Dasher. It also satisfies
	// the Rasterizer interface, and can only perform a fill on the path.

	offsetPath := &MatrixAdder{Adder: f, M: math32.Identity2().Translate(180, 180)}

	p.AddTo(offsetPath)

	scanner.SetColor(radial)
	f.Draw()
	f.Clear()

	scanner.SetClip(image.Rect(420, 350, 460, 400))
	offsetPath.M = math32.Identity2().Translate(340, 180)
	scanner.SetColor(radial)
	p.AddTo(offsetPath)
	f.Draw()
	f.Clear()
	scanner.SetClip(image.ZR)
	offsetPath.M = math32.Identity2().Translate(180, 340)
	p.AddTo(offsetPath)
	f.Draw()
	f.Clear()
	offsetPath.Reset()
	if isClose(offsetPath.M, math32.Identity2(), 1e-12) == false {
		t.Error("path reset failed", offsetPath)
	}

	scanner.SetColor(linear)
	p.AddTo(f)
	f.Draw()
	f.Clear()

	linear.SetSpread(gradient.Repeat)