// 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 cx, cy, cw, ch, midy int
	message := "Now is the time for all good men to come to the aid of the party"

	w, h := openvg.Init()
	var speed openvg.VGfloat = 15.0
	var x openvg.VGfloat = 0
	midy = (h / 2)
	fontsize := w / 50
	cx = 0
	ch = fontsize * 2
	cw = w
	cy = midy - (ch / 2)

	rx, ry, rw, rh := openvg.VGfloat(cx), openvg.VGfloat(cy), openvg.VGfloat(cw), openvg.VGfloat(ch)
	// scroll the text, only in the clipping rectangle
	for x = 0; x < rw+speed; x += speed {
		openvg.Start(w, h)
		openvg.Background(255, 255, 255)
		openvg.FillRGB(0, 0, 0, .2)
		openvg.Rect(rx, ry, rw, rh)
		openvg.ClipRect(cx, cy, cw, ch)
		openvg.Translate(x, ry+openvg.VGfloat(fontsize/2))
		openvg.FillRGB(0, 0, 0, 1)
		openvg.Text(0, 0, message, "sans", fontsize)
		openvg.ClipEnd()
		openvg.End()
	}
	bufio.NewReader(os.Stdin).ReadBytes('\n')
	openvg.Finish()
	os.Exit(0)
}

func paintBG(w, h openvg.VGfloat) {
	if !showTrails {
		openvg.Background(0, 0, 0)
		return
	}
	openvg.FillRGB(0, 0, 0, 0.3)
	openvg.Rect(0, 0, w, h)
}

// testpattern shows a test pattern
func testpattern(w, h int, s string) {
	var midx, midy1, midy2, midy3 float64
	fontsize := 256
	h2 := float64(h / 2)
	by := float64(h - 100)
	bx := float64(w - 100)
	tw1 := &FW{"mono", 0, fontsize}
	tw2 := &FW{"sans", 0, fontsize}
	tw3 := &FW{"serif", 0, fontsize}

	openvg.Start(w, h)

	// colored squares in the corners
	openvg.FillRGB(255, 0, 0, 1)
	openvg.Rect(0, 0, 100, 100)
	openvg.FillRGB(0, 255, 0, 1)
	openvg.Rect(0, by, 100, 100)
	openvg.FillRGB(0, 0, 255, 1)
	openvg.Rect(bx, 0, 100, 100)
	openvg.FillRGB(128, 128, 128, 1)
	openvg.Rect(bx, by, 100, 100)

	// for each font, (Sans, Serif, Mono), adjust the string to the w
	tw1.fitwidth(w, 20, s)
	tw2.fitwidth(w, 20, s)
	tw3.fitwidth(w, 20, s)

	midx = float64(w / 2)

	// Adjust the baselines to be medial
	midy1 = h2 + 20 + float64((tw1.fontsize)/2)
	midy2 = h2 - float64((tw2.fontsize)/2)
	midy3 = h2 - 20 - float64(tw2.fontsize) - float64((tw3.fontsize)/2)

	openvg.FillRGB(128, 128, 128, 1)
	openvg.TextMid(midx, midy1, s, tw1.font, tw1.fontsize)
	openvg.FillRGB(128, 0, 0, 1)
	openvg.TextMid(midx, midy2, s, tw2.font, tw2.fontsize)
	openvg.FillRGB(0, 0, 128, 1)
	openvg.TextMid(midx, midy3, s, tw3.font, tw3.fontsize)
	openvg.End()
}

// countdown shows a countdown display to the top of minute
func (d *display) countdown() {
	tick := time.NewTicker(1 * time.Second)
	ty := d.height / 2
	th := d.height / 20
	size := d.width / 70
	for delay := 60 - time.Now().Second(); delay > 0; delay-- {
		select {
		case <-tick.C:
			tx := d.width * (openvg.VGfloat(60-delay) / 60)
			openvg.BackgroundColor(d.bgcolor)
			openvg.FillColor("black")
			openvg.Rect(0, ty, d.width, th)
			openvg.FillColor("white")
			openvg.TextEnd(tx, ty+(th/4), fmt.Sprintf("start in %d ", delay), "sans", int(size))
			openvg.Rect(tx, ty, d.width-tx, th)
			openvg.End()
		}
	}
	openvg.BackgroundColor(d.bgcolor)
}

// main plots data from specified files or standard input in a
// grid where plotc specifies the number of columns.
func main() {
	w, h := openvg.Init()
	openvg.Start(w, h)
	openvg.FillColor("white")
	openvg.Rect(0, 0, gwidth, gheight)
	filenames := flag.Args()
	if len(filenames) == 0 {
		doplot(beginx, beginy, "")
	} else {
		plotgrid(beginx, beginy, filenames)
	}
	openvg.SaveEnd("vgplot.raw")
	bufio.NewReader(os.Stdin).ReadByte()
	openvg.Finish()
}

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 imagetable(w, h int) {
	imgw, imgh := 422, 238
	itable := []it{
		{"desert0.jpg", imgw, imgh},
		{"desert1.jpg", imgw, imgh},
		{"desert2.jpg", imgw, imgh},
		{"desert3.jpg", imgw, imgh},
		{"desert4.jpg", imgw, imgh},
		{"desert5.jpg", imgw, imgh},
		{"desert6.jpg", imgw, imgh},
		{"desert7.jpg", imgw, imgh},
		//{"http://farm4.static.flickr.com/3546/3338566612_9c56bfb53e_m.jpg", 240, 164},
		//{"http://farm4.static.flickr.com/3642/3337734413_e36baba755_m.jpg", 240, 164},
	}
	offset := openvg.VGfloat(50)
	left := offset
	bot := openvg.VGfloat(h-imgh) - offset
	gutter := offset
	x := left
	y := bot
	openvg.Start(w, h)
	openvg.BackgroundColor("black")
	for _, iname := range itable {
		openvg.Image(x, y, iname.width, iname.height, iname.name)
		openvg.FillRGB(255, 255, 255, 0.3)
		openvg.Rect(x, y, openvg.VGfloat(imgw), 32)
		openvg.FillRGB(0, 0, 0, 1)
		openvg.TextMid(x+openvg.VGfloat(imgw/2), y+10, iname.name, "sans", 16)
		x += openvg.VGfloat(iname.width) + gutter
		if x > openvg.VGfloat(w) {
			x = left
			y -= openvg.VGfloat(iname.height) + gutter
		}
	}
	y = openvg.VGfloat(h) * 0.1
	openvg.FillRGB(128, 128, 128, 1)
	openvg.TextMid(openvg.VGfloat(w/2), 100, "Joshua Tree National Park", "sans", 48)
	openvg.End()
}

func imagetable(w, h int) {
	imgw, imgh := 422, 238
	itable := []string{
		"desert0.jpg",
		"desert1.jpg",
		"desert2.jpg",
		"desert3.jpg",
		"desert4.jpg",
		"desert5.jpg",
		"desert6.jpg",
		"desert7.jpg",
	}
	left := 50.0
	bot := float64(h-imgh) - 50.0
	gutter := 50.0
	x := left
	y := bot
	openvg.Start(w, h)
	openvg.BackgroundColor("black")
	for _, iname := range itable {
		openvg.Image(x, y, imgw, imgh, iname)
		openvg.FillRGB(255, 255, 255, 0.3)
		openvg.Rect(x, y, float64(imgw), 32)
		openvg.FillRGB(0, 0, 0, 1)
		openvg.TextMid(x+float64(imgw/2), y+10, iname, "sans", 16)
		x += float64(imgw) + gutter
		if x > float64(w) {
			x = left
			y -= float64(imgh) + gutter
		}
	}
	y = float64(h) * 0.1
	openvg.FillRGB(128, 128, 128, 1)
	openvg.TextMid(float64(w/2), 100, "Joshua Tree National Park", "sans", 48)
	openvg.End()
}

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()
}

// makepi draws the Raspberry Pi
func makepi(x, y, w, h openvg.VGfloat) {
	// dimensions
	socw := h / 5
	compw := h / 5
	cjw := h / 10
	cjh := h / 8
	audw := h / 5
	aujw := h / 10
	aujh := cjh / 2
	hdw := w / 6
	hdh := w / 10
	gpw := w / 3
	gph := h / 8
	pw := h / 10
	usw := w / 5
	ush := h / 5
	etw := w / 5
	eth := h / 5
	sdw := w / 6
	sdh := w / 4
	offset := (w / 2) / 10
	w34 := (w * 3) / 4
	w2 := w / 2
	h2 := h / 2
	h40 := (h * 2) / 5

	openvg.FillRGB(0, 128, 0, 1)
	openvg.Rect(x, y, w, h) // board

	openvg.FillRGB(255, 255, 0, 1)
	openvg.Rect(x+w2, (y+h)-compw, compw, compw) // composite
	openvg.FillRGB(192, 192, 192, 1)
	openvg.Rect(x+w2+(cjw/2), y+h, cjw, cjh) // composite jack

	openvg.FillRGB(0, 0, 0, 1)
	openvg.Rect(x+w34, y+h-audw, audw, audw)     // audio
	openvg.Rect(x+w34+(aujw/2), y+h, aujw, aujh) // audio jack

	openvg.FillRGB(192, 192, 192, 1)
	openvg.Rect(x+w2, y, hdw, hdh)                 // HDMI
	openvg.Rect((x+w)-etw, y, etw, eth)            // Ethernet
	openvg.Rect((x+w+offset)-usw, y+h40, usw, ush) // USB
	openvg.Rect(x, y, pw, pw)                      // Power

	openvg.FillRGB(0, 0, 0, 1)
	openvg.Rect(x+(w*2)/5, y+h40, socw, socw) // SoC
	openvg.Rect(x, (y+h)-gph, gpw, gph)       // GPIO
	openvg.FillRGB(0, 0, 255, 1)
	openvg.Rect(x-sdw, (y+h2)-(sdh/2), sdw, sdh) // SD card
}

// 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.........

// 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.........

// regionFill colors a rectangular region, and sets the fill color for subsequent text
func (d *dimen) regionFill(bgcolor, textcolor string) {
	openvg.FillColor(bgcolor)
	openvg.Rect(d.x, d.y, d.width, d.height)
	openvg.FillColor(textcolor)
}