// cloud shows the cloudy icon
func (d *dimen) cloud(color string) {
	x, y, w, h := d.x, d.y, d.width, d.height
	radius := d.width / 3
	r2 := radius * 1.8
	openvg.FillColor(color)
	openvg.Circle(x+w*0.25, y+h*0.25, radius)
	openvg.Circle(x+w*0.30, y+h*0.45, radius)
	openvg.Circle(x+w*0.60, y+h*0.40, r2)
}

// moon shows the icon for clear weather at night
func (d *dimen) moon(bg, fg string) {
	x, y, w, h := d.x, d.y, d.width, d.height
	cx := x + w/2
	cy := y + h/2
	w2 := w / 2
	openvg.FillColor(fg)
	openvg.Circle(cx, cy, w2)
	openvg.FillColor(bg)
	openvg.Circle(x+w*0.65, cy, w2)
}

//planets is an exploration of scale
func planets(width, height int, message string) {

	w := float64(width)
	h := float64(height)
	y := h / 2

	margin := 100.0
	minsize := 7.0
	labeloc := 100.0
	bgcolor := "black"
	labelcolor := "white"
	maxsize := (h / 2) * 0.05

	origin := sun.distance
	mostDistant := neptune.distance
	firstSize := mercury.radius
	lastSize := neptune.radius

	openvg.Start(width, height)
	openvg.BackgroundColor(bgcolor)

	for _, p := range SolarSystem {
		x := vmap(p.distance, origin, mostDistant, margin, w-margin)
		r := vmap(p.radius, firstSize, lastSize, minsize, maxsize)

		if p.name == "Sun" {
			openvg.FillRGB(p.color.Red, p.color.Green, p.color.Blue, 1)
			openvg.Circle(margin-(r/2), y, r)
		} else {
			light(x, y, r, p.color)
			openvg.Circle(x, y, r)
			if p.name == "Saturn" {
				ringwidth := r * 2.35 // Saturn's rings are over 2x the planet radius
				openvg.StrokeWidth(3)
				openvg.StrokeRGB(p.color.Red, p.color.Green, p.color.Blue, 1)
				openvg.Line((x - ringwidth/2), y, (x + ringwidth/2), y)
				openvg.StrokeWidth(0)
			}
		}
		if p.name == "Earth" && len(message) > 1 {
			openvg.StrokeColor(labelcolor)
			openvg.StrokeWidth(1)
			openvg.Line(x, y+(r/2), x, y+labeloc)
			openvg.StrokeWidth(0)
			openvg.FillColor(labelcolor)
			openvg.TextMid(x, y+labeloc+10, message, "sans", 12)
		}
	}
	openvg.End()
}

func main() {

	width, height := openvg.Init()

	w := openvg.VGfloat(width)
	h := openvg.VGfloat(height)
	y := h / 2
	var (
		margin  openvg.VGfloat = 100.0
		minsize openvg.VGfloat = 7.0
		labeloc openvg.VGfloat = 100.0
	)
	bgcolor := "black"
	labelcolor := "white"
	maxsize := (h / 2) * 0.05

	origin := sun.distance
	mostDistant := neptune.distance
	firstSize := mercury.radius
	lastSize := neptune.radius

	openvg.Start(width, height)
	openvg.BackgroundColor(bgcolor)

	for _, p := range solarSystem {
		x := vmap(p.distance, origin, mostDistant, margin, w-margin)
		r := vmap(p.radius, firstSize, lastSize, minsize, maxsize)

		if p.name == "Sun" {
			openvg.FillRGB(p.color.Red, p.color.Green, p.color.Blue, 1)
			openvg.Circle(margin-(r/2), y, r)
		} else {
			light(x, y, r, p.color)
			openvg.Circle(x, y, r)
		}
		if p.name == "Earth" && len(os.Args) > 1 {
			openvg.StrokeColor(labelcolor)
			openvg.StrokeWidth(1)
			openvg.Line(x, y+(r/2), x, y+labeloc)
			openvg.StrokeWidth(0)
			openvg.FillColor(labelcolor)
			openvg.TextMid(x, y+labeloc+10, os.Args[1], "sans", 12)
		}
	}
	openvg.End()
	bufio.NewReader(os.Stdin).ReadByte()
	openvg.Finish()
}

// rshapes draws shapes with random colors, openvg.Strokes, and sizes.
func rshapes(width, height, n int) {

	var sx, sy, cx, cy, px, py, ex, ey, pox, poy float64

	np := 10
	polyx := make([]float64, np)
	polyy := make([]float64, np)
	openvg.Start(width, height)
	for i := 0; i < n; i++ {
		openvg.FillRGB(randcolor(), randcolor(), randcolor(), rand.Float64())
		openvg.Ellipse(randf(width), randf(height), randf(200), randf(100))
		openvg.Circle(randf(width), randf(height), randf(100))
		openvg.Rect(randf(width), randf(height), randf(200), randf(100))
		openvg.Arc(randf(width), randf(height), randf(200), randf(200), randf(360), randf(360))

		sx = randf(width)
		sy = randf(height)
		openvg.StrokeRGB(randcolor(), randcolor(), randcolor(), 1)
		openvg.StrokeWidth(randf(5))
		openvg.Line(sx, sy, sx+randf(200), sy+randf(100))
		openvg.StrokeWidth(0)

		sx = randf(width)
		sy = randf(height)
		ex = sx + randf(200)
		ey = sy
		cx = sx + ((ex - sx) / 2.0)
		cy = sy + randf(100)
		openvg.Qbezier(sx, sy, cx, cy, ex, ey)

		sx = randf(width)
		sy = randf(height)
		ex = sx + randf(200)
		ey = sy
		cx = sx + ((ex - sx) / 2.0)
		cy = sy + randf(100)
		px = cx
		py = sy - randf(100)
		openvg.Cbezier(sx, sy, cx, cy, px, py, ex, ey)

		pox = randf(width)
		poy = randf(height)
		for j := 0; j < np; j++ {
			polyx[j] = pox + randf(200)
			polyy[j] = poy + randf(100)
		}
		openvg.Polygon(polyx, polyy) // , np)

		pox = randf(width)
		poy = randf(height)
		for j := 0; j < np; j++ {
			polyx[j] = pox + randf(200)
			polyy[j] = poy + randf(100)
		}
		openvg.Polyline(polyx, polyy) // , np)
	}
	openvg.FillRGB(128, 0, 0, 1)
	openvg.Text(20, 20, "OpenVG on the Raspberry Pi", "sans", 32)
	openvg.End()
}

func main() {
	var color string
	openvg.Start(width, height)
	openvg.Background(200, 200, 200)
	for i := 0; i < niter; i++ {
		x := random(0, width)
		y := random(height/3, (height*2)/3)
		r := random(0, 10000)
		switch {
		case r >= 0 && r <= 2500:
			color = "white"
		case r > 2500 && r <= 5000:
			color = "maroon"
		case r > 5000 && r <= 7500:
			color = "gray"
		case r > 7500 && r <= 10000:
			color = "black"
		}
		openvg.FillColor(color, openvg.VGfloat(opacity))
		openvg.Circle(openvg.VGfloat(x), openvg.VGfloat(y), openvg.VGfloat(size))
	}
	openvg.End()
	bufio.NewReader(os.Stdin).ReadByte()
	openvg.Finish()
}

// sunearth shows the relative sizes of the sun and the earth
func sunearth(w, h int) {
	var sun, earth, x, y float64

	openvg.Start(w, h)
	openvg.Background(0, 0, 0)
	openvg.FillRGB(255, 255, 255, 1)
	for i := 0; i < w/4; i++ {
		x = randf(w)
		y = randf(h)
		openvg.Circle(x, y, 2)
	}
	earth = float64(w) * 0.010
	sun = earth * 109
	openvg.FillRGB(0, 0, 255, 1)
	openvg.Circle(float64(w/3), float64(h-(h/10)), earth)
	openvg.FillRGB(255, 255, 224, 1)
	openvg.Circle(float64(w), 0, sun)
	openvg.End()
}

func draw(w, h openvg.VGfloat) {
	paintBG(w, h)

	var p particle
	var grav = openvg.VGfloat(gravity)
	for i := 0; i < nparticles; i++ {
		p = particles[i]
		openvg.FillRGB(p.r, p.g, p.b, 1)
		openvg.Circle(p.x, p.y, p.radius)

		// Apply the velocity
		p.x += p.vx
		p.y += p.vy

		p.vx *= 0.98
		if p.vy > 0 {
			p.vy *= 0.97
		}

		// Gravity
		p.vy -= grav

		// Stop p leaving the canvas
		if p.x < -50 {
			p.x = w + 50
		}
		if p.x > w+50 {
			p.x = -50
		}

		// When particle reaches the bottom of screen reset velocity & start posn
		if p.y < -50 {
			p.x = 0
			p.y = 0
			p.vx = openvg.VGfloat(rand.Intn(maxrand)%30) + 30
			p.vy = openvg.VGfloat(rand.Intn(maxrand)%20) + 40

			if directionRTL {
				p.vx *= -1
				p.x = w
			}
		}

		if p.y > h+50 {
			p.y = -50
		}
		particles[i] = p
	}
	openvg.End()
}

func main() {
	width, height := openvg.Init() // OpenGL, etc initialization

	w2 := float64(width / 2)
	h2 := float64(height / 2)
	w := float64(width)

	openvg.Start(width, height)                               // Start the picture
	openvg.BackgroundColor("black")                           // Black background
	openvg.FillRGB(44, 77, 232, 1)                            // Big blue marble
	openvg.Circle(w2, 0, w)                                   // The "world"
	openvg.FillColor("white")                                 // White text
	openvg.TextMid(w2, h2, "hello, world", "serif", width/10) // Greetings
	openvg.SaveEnd("hello.raw")                               // End the picture
	bufio.NewReader(os.Stdin).ReadBytes('\n')                 // Pause until [RETURN]
	openvg.Finish()                                           // Graphics cleanup
}

// sun shows the icon for clear weather
func (d *dimen) sun(color string) {
	x, y, w, h := d.x, d.y, d.width, d.height
	cx := x + (w / 2)
	cy := y + (h / 2)
	r0 := w * 0.50
	r1 := w * 0.45
	r2 := w * 0.30
	openvg.FillColor(color)
	openvg.Circle(cx, cy, r0)
	openvg.StrokeColor(color)
	openvg.StrokeWidth(w / 30)
	for t := 0.0; t < 2*math.Pi; t += math.Pi / 6 {
		c := openvg.VGfloat(math.Cos(t))
		s := openvg.VGfloat(math.Sin(t))
		x1 := (r1 * c) + cx
		y1 := (r1 * s) + cy
		x2 := (r2 * c) + cx
		y2 := (r2 * s) + cy
		openvg.Line(x1, y1, x2, y2)
	}
	openvg.StrokeWidth(0)
}

func main() {
	width, height := openvg.Init() // OpenGL, etc initialization

	w2 := float64(width / 2)
	h2 := float64(height / 2)
	w := float64(width)

	stops := []openvg.Offcolor{
		{0.0, openvg.RGB{44, 100, 232}, 1.0}, // blue-ish
		{0.5, openvg.RGB{22, 50, 151}, 1.0},  // darker blue
		{1.0, openvg.RGB{88, 200, 255}, 1.0}, // lighter blue
	}

	openvg.Start(width, height)                               // Start the picture
	openvg.BackgroundColor("black")                           // Black background
	openvg.FillRadialGradient(w2, 0, w2, w2, w*.5, stops)     // Big blue marble
	openvg.Circle(w2, 0, w)                                   // The "world"
	openvg.FillColor("white")                                 // White text
	openvg.TextMid(w2, h2, "hello, world", "serif", width/10) // Greetings
	openvg.SaveEnd("hvg.raw")                                 // End the picture
	bufio.NewReader(os.Stdin).ReadBytes('\n')                 // Pause until [RETURN]
	openvg.Finish()                                           // Graphics cleanup
}

func gradient(width, height int) {
	w := float64(width)
	h := float64(height)
	stops := []openvg.Offcolor{
		{0.0, openvg.RGB{255, 255, 255}, 1.0},
		{0.5, openvg.RGB{128, 128, 128}, 1.0},
		{1.0, openvg.RGB{0, 0, 0}, 1.0},
	}

	x1 := w / 8
	x2 := (w * 3) / 8
	y1 := h / 3
	y2 := (h * 2) / 3
	cx := (w * 3) / 4
	cy := (h / 2)
	r := (x2 - x1)
	fx := cx + (r / 4)
	fy := cy + (r / 4)
	openvg.Start(width, height)
	openvg.BackgroundRGB(128, 128, 128, 1)
	openvg.FillLinearGradient(x1, y1, x2, y2, stops)
	openvg.Rect(x1, y1, x2-x1, y2-y1)
	openvg.FillRadialGradient(cx, cy, fx, fy, r, stops)
	openvg.Circle(cx, cy, r)

	openvg.FillRGB(0, 0, 0, 0.3)
	openvg.Circle(x1, y1, 10)
	openvg.Circle(x2, y2, 10)
	openvg.Circle(cx, cy, 10)
	openvg.Circle(cx+r/2, cy, 10)
	openvg.Circle(fx, fy, 10)

	openvg.FillColor("black")
	SansTypeface := "sans"
	openvg.TextMid(x1, y1-20, "(x1, y1)", SansTypeface, 18)
	openvg.TextMid(x2, y2+10, "(x2, y2)", SansTypeface, 18)
	openvg.TextMid(cx, cy, "(cx, cy)", SansTypeface, 18)
	openvg.TextMid(fx, fy, "(fx, fy)", SansTypeface, 18)
	openvg.TextEnd(cx+(r/2)+20, cy, "r", SansTypeface, 18)

	openvg.TextMid(x1+((x2-x1)/2), h/6, "Linear Gradient", SansTypeface, 36)
	openvg.TextMid(cx, h/6, "Radial Gradient", SansTypeface, 36)
	openvg.End()
}

func main() {
	var nr = flag.Int("n", 500, "number of objects")
	var message = flag.String("m", "Go/OpenVG", "message")
	var bgcolor = flag.String("bg", "white", "background color")
	var fgcolor = flag.String("fg", "maroon", "text color")

	flag.Parse()
	rseed()

	width, height := openvg.Init()
	fw := openvg.VGfloat(width)
	fh := openvg.VGfloat(height)

	openvg.Start(width, height)
	openvg.BackgroundColor(*bgcolor)
	for i := 0; i < *nr; i++ {

		red := uint8(rand.Intn(255))
		green := uint8(rand.Intn(255))
		blue := uint8(rand.Intn(255))
		alpha := randf()

		x := randf() * fw
		y := randf() * fh
		radius := randf() * fw / 10

		openvg.FillRGB(red, green, blue, alpha)
		openvg.Circle(x, y, radius)
	}
	openvg.FillColor(*fgcolor)
	openvg.TextMid(fw/2, fh/2, *message, "sans", width/25)
	openvg.End()

	bufio.NewReader(os.Stdin).ReadBytes('\n')
	openvg.Finish()
}

// plot places a plot at the specified location with the specified dimemsions
// using the specified settings, using the specified data
func plot(x, y, w, h float64, settings plotset, d []rawdata) {
	nd := len(d)
	if nd < 2 {
		fmt.Fprintf(os.Stderr, "%d is not enough points to plot\n", len(d))
		return
	}
	// Compute the minima and maxima of the data
	maxx, minx := d[0].x, d[0].x
	maxy, miny := d[0].y, d[0].y
	for _, v := range d {

		if v.x > maxx {
			maxx = v.x
		}
		if v.y > maxy {
			maxy = v.y
		}
		if v.x < minx {
			minx = v.x
		}
		if v.y < miny {
			miny = v.y
		}
	}
	// Prepare for a area or line chart by allocating
	// polygon coordinates; for the horizon plot, you need two extra coordinates
	// for the extrema.
	needpoly := settings.opt["area"] || settings.opt["connect"]
	var xpoly, ypoly []float64
	if needpoly {
		xpoly = make([]float64, nd+2)
		ypoly = make([]float64, nd+2)
		// preload the extrema of the polygon,
		// the bottom left and bottom right of the plot's rectangle
		xpoly[0] = x
		ypoly[0] = y
		xpoly[nd+1] = x + w
		ypoly[nd+1] = y
	}
	// Draw the plot's bounding rectangle
	if settings.opt["showbg"] && !settings.opt["sameplot"] {
		openvg.FillColor(settings.attr["bgcolor"])
		openvg.Rect(x, y, w, h)
	}
	// Loop through the data, drawing items as specified
	spacer := 10.0
	for i, v := range d {
		xp := fmap(v.x, minx, maxx, x, x+w)
		yp := fmap(v.y, miny, maxy, y, y+h)
		if needpoly {
			xpoly[i+1] = xp
			ypoly[i+1] = yp
		}
		if settings.opt["showbar"] {
			openvg.StrokeColor(settings.attr["barcolor"])
			openvg.StrokeWidth(settings.size["barsize"])
			openvg.Line(xp, yp, xp, y)
		}
		if settings.opt["showdot"] {
			openvg.FillColor(settings.attr["dotcolor"])
			openvg.StrokeWidth(0)
			openvg.Circle(xp, yp, settings.size["dotsize"])
		}
		if settings.opt["showx"] {
			if i%int(settings.size["xinterval"]) == 0 {
				openvg.FillColor("black")
				openvg.TextMid(xp, y-(spacer*2), fmt.Sprintf("%d", int(v.x)), settings.attr["font"], int(settings.size["fontsize"]))
				openvg.StrokeColor("silver")
				openvg.StrokeWidth(1)
				openvg.Line(xp, y, xp, y-spacer)
			}
			openvg.StrokeWidth(0)
		}
	}
	// Done constructing the points for the area or line plots, display them in one shot
	if settings.opt["area"] {
		openvg.FillColor(settings.attr["areacolor"])
		openvg.Polygon(xpoly, ypoly)
	}

	if settings.opt["connect"] {
		openvg.StrokeColor(settings.attr["linecolor"])
		openvg.StrokeWidth(settings.size["linesize"])
		openvg.Polyline(xpoly[1:nd+1], ypoly[1:nd+1])
	}
	// Put on the y axis labels, if specified
	if settings.opt["showy"] {
		bot := math.Floor(miny)
		top := math.Ceil(maxy)
		yrange := top - bot
		interval := yrange / float64(settings.size["yinterval"])
		for yax := bot; yax <= top; yax += interval {
			yaxp := fmap(yax, bot, top, float64(y), float64(y+h))
			openvg.FillColor("black")
			openvg.TextEnd(x-spacer, yaxp, fmt.Sprintf("%.1f", yax), settings.attr["font"], int(settings.size["fontsize"]))
			openvg.StrokeColor("silver")
			openvg.StrokeWidth(1)
			openvg.Line(x-spacer, yaxp, x, yaxp)
//.........这里部分代码省略.........

func main() {
	var (
		filename     = flag.String("f", "svgcolors.txt", "input file")
		fontname     = flag.String("font", "sans", "fontname")
		neg          = flag.Bool("neg", false, "negative")
		showrgb      = flag.Bool("rgb", false, "show RGB")
		showcode     = flag.Bool("showcode", true, "show colors and codes")
		circsw       = flag.Bool("circle", true, "circle swatch")
		outline      = flag.Bool("outline", false, "outline swatch")
		fontsize     = flag.Int("fs", 12, "fontsize")
		rowsize      = flag.Int("r", 32, "rowsize")
		colw         = flag.Float64("c", 340, "column size")
		swatch       = flag.Float64("s", 16, "swatch size")
		gutter       = flag.Float64("g", 12, "gutter")
		err          error
		tcolor, line string
	)

	flag.Parse()
	f, oerr := os.Open(*filename)
	if oerr != nil {
		fmt.Fprintf(os.Stderr, "%v\n", oerr)
		return
	}
	width, height := openvg.Init()

	openvg.Start(width, height)
	fw := openvg.VGfloat(width)
	fh := openvg.VGfloat(height)
	if *neg {
		openvg.FillColor("black")
		openvg.Rect(0, 0, fw, fh)
		tcolor = "white"
	} else {
		openvg.FillColor("white")
		openvg.Rect(0, 0, fw, fh)
		tcolor = "black"
	}
	top := fh - 32.0
	left := openvg.VGfloat(32.0)
	cw := openvg.VGfloat(*colw)
	sw := openvg.VGfloat(*swatch)
	g := openvg.VGfloat(*gutter)
	in := bufio.NewReader(f)

	for x, y, nr := left, top, 0; err == nil; nr++ {
		line, err = in.ReadString('\n')
		fields := strings.Split(strings.TrimSpace(line), "\t")
		if nr%*rowsize == 0 && nr > 0 {
			x += cw
			y = top
		}
		if len(fields) == 3 {
			var red, green, blue uint8
			fmt.Sscanf(fields[2], "%d,%d,%d", &red, &green, &blue)
			openvg.FillRGB(red, green, blue, 1)
			if *outline {
				openvg.StrokeColor("black")
				openvg.StrokeWidth(1)
			}
			if *circsw {
				openvg.Circle(x+sw/2, y+sw/2, sw)
			} else {
				openvg.Rect(x, y, sw, sw)
			}
			openvg.StrokeWidth(0)
			openvg.FillColor(tcolor)
			openvg.Text(x+sw+openvg.VGfloat(*fontsize/2), y, fields[0], *fontname, *fontsize)
			var label string
			if *showcode {
				if *showrgb {
					label = fields[1]
				} else {
					label = fields[2]
				}
				openvg.FillColor("gray")
				openvg.TextEnd(x+cw-(sw+g), y, label, *fontname, *fontsize)
			}
		}
		y -= (sw + g)
	}
	openvg.End()
	bufio.NewReader(os.Stdin).ReadBytes('\n')
	openvg.Finish()
}

// refcard shows a reference card of shapes
func refcard(width, height int) {
	shapenames := []string{
		"Circle",
		"Ellipse",
		"Rectangle",
		"Rounded Rectangle",
		"Line",
		"Polyline",
		"Polygon",
		"Arc",
		"Quadratic Bezier",
		"Cubic Bezier",
		"Image",
	}
	top := float64(height) * .95
	sx := float64(width) * 0.10
	sy := top
	sw := float64(width) * .05
	sh := float64(height) * .045
	dotsize := 7.0
	spacing := 2.0
	fontsize := int(float64(height) * .033)
	shapecolor := Color{202, 225, 255, 1.0}

	openvg.Start(width, height)
	openvg.FillRGB(128, 0, 0, 1)
	openvg.TextEnd(float64(width-20), float64(height/2),
		"OpenVG on the Raspberry Pi", "sans", fontsize+(fontsize/2))
	openvg.FillRGB(0, 0, 0, 1)
	for _, s := range shapenames {
		openvg.Text(sx+sw+sw/2, sy, s, "sans", fontsize)
		sy -= sh * spacing
	}
	sy = top
	cx := sx + (sw / 2)
	ex := sx + sw
	openvg.FillRGB(shapecolor.red, shapecolor.green, shapecolor.blue, shapecolor.alpha)
	openvg.Circle(cx, sy, sw)
	coordpoint(cx, sy, dotsize, shapecolor)
	sy -= sh * spacing
	openvg.Ellipse(cx, sy, sw, sh)
	coordpoint(cx, sy, dotsize, shapecolor)
	sy -= sh * spacing
	openvg.Rect(sx, sy, sw, sh)
	coordpoint(sx, sy, dotsize, shapecolor)
	sy -= sh * spacing
	openvg.Roundrect(sx, sy, sw, sh, 20, 20)
	coordpoint(sx, sy, dotsize, shapecolor)
	sy -= sh * spacing

	openvg.StrokeWidth(1)
	openvg.StrokeRGB(204, 204, 204, 1)
	openvg.Line(sx, sy, ex, sy)
	coordpoint(sx, sy, dotsize, shapecolor)
	coordpoint(ex, sy, dotsize, shapecolor)
	sy -= sh

	px := []float64{sx, sx + (sw / 4), sx + (sw / 2), sx + ((sw * 3) / 4), sx + sw}
	py := []float64{sy, sy - sh, sy, sy - sh, sy}

	openvg.Polyline(px, py) // , 5)
	coordpoint(px[0], py[0], dotsize, shapecolor)
	coordpoint(px[1], py[1], dotsize, shapecolor)
	coordpoint(px[2], py[2], dotsize, shapecolor)
	coordpoint(px[3], py[3], dotsize, shapecolor)
	coordpoint(px[4], py[4], dotsize, shapecolor)
	sy -= sh * spacing

	py[0] = sy
	py[1] = sy - sh
	py[2] = sy - (sh / 2)
	py[3] = py[1] - (sh / 4)
	py[4] = sy
	openvg.Polygon(px, py) // , 5)
	sy -= (sh * spacing) + sh

	openvg.Arc(sx+(sw/2), sy, sw, sh, 0, 180)
	coordpoint(sx+(sw/2), sy, dotsize, shapecolor)
	sy -= sh * spacing

	var cy, ey float64
	cy = sy + (sh / 2)
	ey = sy
	openvg.Qbezier(sx, sy, cx, cy, ex, ey)
	coordpoint(sx, sy, dotsize, shapecolor)
	coordpoint(cx, cy, dotsize, shapecolor)
	coordpoint(ex, ey, dotsize, shapecolor)
	sy -= sh * spacing

	ey = sy
	cy = sy + sh
	openvg.Cbezier(sx, sy, cx, cy, cx, sy, ex, ey)
	coordpoint(sx, sy, dotsize, shapecolor)
	coordpoint(cx, cy, dotsize, shapecolor)
	coordpoint(cx, sy, dotsize, shapecolor)
	coordpoint(ex, ey, dotsize, shapecolor)

	sy -= (sh * spacing * 1.5)
	openvg.Image(sx, sy, 110, 110, "starx.jpg")
//.........这里部分代码省略.........

// coordpoint marks a coordinate, preserving a previous color
func coordpoint(x, y, size float64, c Color) {
	openvg.FillRGB(128, 0, 0, 0.3)
	openvg.Circle(x, y, size)
	openvg.FillRGB(c.red, c.green, c.blue, c.alpha)
}