Golang github.com-ajstarks-openvg.VGfloat类(方法)实例源码

// imgtest draws images at the corners and center
func imagetest(w, h int) {
	openvg.Start(w, h)
	imgw := 422
	imgh := 238
	fiw := openvg.VGfloat(imgw)
	fih := openvg.VGfloat(imgh)
	fw := openvg.VGfloat(w)
	fh := openvg.VGfloat(h)
	vgzero := openvg.VGfloat(0.0)
	cx := (fw / 2) - (fiw / 2)
	cy := (fh / 2) - (fih / 2)
	ulx := vgzero
	uly := fh - fih
	urx := fw - fiw
	ury := uly
	llx := vgzero
	lly := vgzero
	lrx := urx
	lry := lly
	openvg.Start(w, h)
	openvg.Background(0, 0, 0)
	openvg.Image(cx, cy, imgw, imgh, "desert1.jpg")
	openvg.Image(ulx, uly, imgw, imgh, "desert2.jpg")
	openvg.Image(urx, ury, imgw, imgh, "desert3.jpg")
	openvg.Image(llx, lly, imgw, imgh, "desert4.jpg")
	openvg.Image(lrx, lry, imgw, imgh, "desert5.jpg")
	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()
}

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)
}

// rain shows raindrops
func (d *dimen) rain(color string) {
	dd := dimen{x: 0, y: 0, width: d.width / 6, height: d.height / 6}
	for i := 0; i < 20; i++ {
		dd.x = d.x + d.width*openvg.VGfloat(rand.Float64())
		dd.y = d.y + d.height*openvg.VGfloat(rand.Float64())
		dd.drop(color)
	}
}

// snow shows the snow icon
func (d *dimen) snow(color string) {
	df := dimen{x: 0, y: 0, width: d.width / 6, height: d.height / 6}
	for i := 0; i < 20; i++ {
		df.x = d.x + d.width*openvg.VGfloat(rand.Float64())
		df.y = d.y + d.height*openvg.VGfloat(rand.Float64())
		df.flake(color)
	}
}

// show the current time, weather and headlines
func main() {
	var (
		section    = flag.String("h", "u.s.", "headline type (arts, health, sports, science, technology, u.s., world, hn)")
		location   = flag.String("loc", "40.6213,-74.4395", "lat,long for weather")
		bgcolor    = flag.String("bg", "slateblue", "background color")
		textcolor  = flag.String("tc", "white", "text color")
		width      = flag.Int("width", 0, "screen width")
		height     = flag.Int("height", 0, "screen height")
		smartcolor = flag.Bool("sc", false, "smart colors")
		thumb      = flag.Bool("tn", false, "show thumbnails")
	)
	flag.Parse()

	// initial display
	dw, dh := openvg.Init()
	if *width > 0 && *height > 0 {
		dw, dh = *width, *height
	}
	openvg.Start(dw, dh)
	canvas := display{
		width:     openvg.VGfloat(dw),
		height:    openvg.VGfloat(dh),
		bgcolor:   *bgcolor,
		textcolor: *textcolor,
	}
	canvas.countdown()
	openvg.End()
	canvas.clock(*smartcolor)
	canvas.weather(*location)
	canvas.headlines(*section, *thumb)

	// update on specific intervals, shutdown on interrupt
	dateticker := time.NewTicker(1 * time.Minute)
	weatherticker := time.NewTicker(5 * time.Minute)
	headticker := time.NewTicker(10 * time.Minute)
	sigint := make(chan os.Signal, 1)
	signal.Notify(sigint, os.Interrupt)

	for {
		select {
		case <-dateticker.C:
			canvas.clock(*smartcolor)
		case <-weatherticker.C:
			canvas.weather(*location)
		case <-headticker.C:
			canvas.headlines(*section, *thumb)
		case <-sigint:
			openvg.Finish()
			os.Exit(0)
		}
	}
}

// raspberry pi, scaled to the screen dimensions
func raspi(w, h int, s string) {
	midx := openvg.VGfloat(w) / 2
	midy := openvg.VGfloat(h) / 2
	rw := midx
	rh := (rw * 2) / 3
	fontsize := w / 25
	openvg.Start(w, h)
	openvg.Background(255, 255, 255)
	makepi(midx-(rw/2), midy-(rh/2), rw, rh)
	openvg.FillRGB(128, 0, 0, 1)
	openvg.TextMid(midx, midy-(rh/2)-openvg.VGfloat(fontsize*2), s, "sans", fontsize)
	openvg.End()
}

func arrowhand(cx, cy, px, py, r openvg.VGfloat, t float64, value int, color string) {
	ax := []openvg.VGfloat{cx, 0, px, 0, cx}
	ay := []openvg.VGfloat{cy, 0, py, 0, cy}
	t = minadjust(t, value) * deg2rad
	rf := float64(r * 0.9)
	tf := math.Pi / 45.0
	ax[1] = cx + openvg.VGfloat(rf*math.Cos(t-tf))
	ay[1] = cy + openvg.VGfloat(rf*math.Sin(t-tf))
	ax[3] = cx + openvg.VGfloat(rf*math.Cos(t+tf))
	ay[3] = cy + openvg.VGfloat(rf*math.Sin(t+tf))
	openvg.FillColor(color)
	openvg.Polygon(ax, ay)
}

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

	w := openvg.VGfloat(width)
	h := openvg.VGfloat(height)
	y := h / 2

	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 == "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 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 combohand(cx, cy, px, py, r, stroke openvg.VGfloat, t float64, value int, color string) {
	thinr := float64(r * 0.25)
	t = minadjust(t, value) * deg2rad
	tx := cx + openvg.VGfloat(thinr*math.Cos(t))
	ty := cy + openvg.VGfloat(thinr*math.Sin(t))
	openvg.FillColor(color)
	openvg.Ellipse(px, py, stroke*2, stroke*2)
	openvg.Ellipse(tx, ty, stroke*2, stroke*2)
	openvg.StrokeWidth(stroke)
	openvg.StrokeColor(color)
	openvg.Line(cx, cy, tx, ty)
	openvg.StrokeWidth(stroke * 2)
	openvg.Line(tx, ty, px, py)
	openvg.StrokeWidth(0)
}

// raspberry pi, scaled to the screen dimensions
func main() {
	w, h := openvg.Init()
	midx := openvg.VGfloat(w) / 2
	midy := openvg.VGfloat(h) / 2
	rw := midx
	rh := (rw * 2) / 3
	fontsize := w / 25
	openvg.Start(w, h)
	openvg.Background(255, 255, 255)
	makepi(midx-(rw/2), midy-(rh/2), rw, rh)
	makepi(200, 100, 75, 50)
	openvg.FillRGB(128, 0, 0, 1)
	openvg.TextMid(midx, midy-(rh/2)-openvg.VGfloat(fontsize*2), "The Raspberry Pi", "sans", fontsize)
	WaitEnd()
}

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()
}

// adjust the font to fit within a width
func (f *FW) fitwidth(width, adj int, s string) {
	f.tw = openvg.TextWidth(s, f.font, f.fontsize)
	for f.tw > openvg.VGfloat(width) {
		f.fontsize -= adj
		f.tw = openvg.TextWidth(s, f.font, f.fontsize)
	}
}

// flake shows the snowflake icon
func (d *dimen) flake(color string) {
	x, y, w, h := d.x, d.y, d.width, d.height
	cx := x + (w / 2)
	cy := y + (h / 2)
	r := w * 0.30
	openvg.StrokeColor(color)
	openvg.StrokeWidth(w / 20)
	for t := 0.0; t < 2*math.Pi; t += math.Pi / 4 {
		c := openvg.VGfloat(math.Cos(t))
		s := openvg.VGfloat(math.Sin(t))
		x1 := (r * c) + cx
		y1 := (r * s) + cy
		openvg.Line(cx, cy, x1, y1)
	}
	openvg.StrokeWidth(0)
}

// 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 openvg.VGfloat

	np := 10
	polyx := make([]openvg.VGfloat, np)
	polyy := make([]openvg.VGfloat, np)
	openvg.Start(width, height)
	for i := 0; i < n; i++ {
		openvg.FillRGB(randcolor(), randcolor(), randcolor(), openvg.VGfloat(rand.Float32()))
		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() {
	width, height := openvg.Init() // OpenGL, etc initialization

	w2 := openvg.VGfloat(width / 2)
	h2 := openvg.VGfloat(height / 2)
	w := openvg.VGfloat(width)

	openvg.Start(width, height)                               // Start the picture
	openvg.BackgroundColor("black")                           // Black background
	openvg.FillRGB(44, 100, 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.End()                                              // End the picture
	bufio.NewReader(os.Stdin).ReadBytes('\n')                 // Pause until [RETURN]
	openvg.Finish()                                           // Graphics cleanup
}

func main() {
	setOptions()
	rand.Seed(time.Now().Unix())
	w, h := openvg.Init()
	width, height := openvg.VGfloat(w), openvg.VGfloat(h)
	initParticles(width, height)
	openvg.Start(w, h)
	i := 0
	for {
		draw(width, height)
		i++
		if alternate && i == nswitch { // switch launch direction every nswitch draws
			directionRTL = !directionRTL
			i = 0
		}
	}
}

// tb draws a block of text
func tb(w, h int) {
	para := []string{
		"For lo,",
		"the winter is past,",
		"the rain is over and gone",
		"the flowers appear on the earth;",
		"the time for the singing of birds is come,",
		"and the voice of the turtle is heard in our land",
	}

	tmargin := openvg.VGfloat(w) * 0.50
	lmargin := openvg.VGfloat(w) * 0.10
	top := openvg.VGfloat(h) * .9
	mid := openvg.VGfloat(h) * .6
	bot := openvg.VGfloat(h) * .3

	fontsize := 24
	leading := openvg.VGfloat(40.0)
	lfontsize := fontsize * 2
	midb := ((leading * 2) + (leading / 2)) - openvg.VGfloat(lfontsize/2)

	openvg.Start(w, h)
	openvg.FillRGB(49, 79, 79, 1)
	textlines(tmargin, top, para, "serif", fontsize, leading)
	textlines(tmargin, mid, para, "sans", fontsize, leading)
	textlines(tmargin, bot, para, "mono", fontsize, leading)
	openvg.Text(lmargin, top-midb, "Serif", "sans", lfontsize)
	openvg.Text(lmargin, mid-midb, "Sans", "sans", lfontsize)
	openvg.Text(lmargin, bot-midb, "Mono", "sans", lfontsize)
	openvg.End()
}

// Initialize _all_ the particles
func initParticles(w, h openvg.VGfloat) {
	particles = make([]particle, nparticles)
	for i := 0; i < nparticles; i++ {
		particles[i].x = 0
		particles[i].y = 0
		particles[i].vx = openvg.VGfloat(rand.Intn(maxrand)%30) + 30
		particles[i].vy = openvg.VGfloat(rand.Intn(maxrand)%20) + 40
		particles[i].r = uint8(rand.Intn(255))
		particles[i].g = uint8(rand.Intn(255))
		particles[i].b = uint8(rand.Intn(255))
		particles[i].radius = openvg.VGfloat(rand.Intn(maxrand)%20) + 20

		if directionRTL {
			particles[i].vx *= -1
			particles[i].x = w
		}
	}
}