//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 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()
}
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()
}
// 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 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()
}
// showgrid xrays a slide
func showgrid(d deck.Deck, n int, p float64) {
w := openvg.VGfloat(d.Canvas.Width)
h := openvg.VGfloat(d.Canvas.Height)
percent := openvg.VGfloat(p)
fs := (w / 100) // labels are 1% of the width
xpct := (percent / 100.0) * w
ypct := (percent / 100.0) * h
openvg.StrokeColor("lightgray", 0.5)
openvg.StrokeWidth(3)
// horizontal gridlines
xl := percent
for x := xpct; x <= w; x += xpct {
openvg.Line(x, 0, x, h)
openvg.Text(x, percent, fmt.Sprintf("%.0f%%", xl), "sans", int(fs))
xl += percent
}
// vertical gridlines
yl := percent
for y := ypct; y <= h; y += ypct {
openvg.Line(0, y, w, y)
openvg.Text(percent, y, fmt.Sprintf("%.0f%%", yl), "sans", int(fs))
yl += percent
}
// show boundary and location of images
if n < 0 || n > len(d.Slide) {
return
}
for _, im := range d.Slide[n].Image {
x := pct(im.Xp, w)
y := pct(im.Yp, h)
iw := openvg.VGfloat(im.Width)
ih := openvg.VGfloat(im.Height)
if im.Scale > 0 {
iw *= openvg.VGfloat(im.Scale / 100)
ih *= openvg.VGfloat(im.Scale / 100)
}
openvg.FillRGB(127, 0, 0, 0.3)
openvg.Circle(x, y, fs)
openvg.FillRGB(255, 0, 0, 0.1)
openvg.Rect(x-iw/2, y-ih/2, iw, ih)
}
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 gradient(width, height int) {
w := openvg.VGfloat(width)
h := openvg.VGfloat(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()
}
func main() {
width, height := openvg.Init() // OpenGL, etc initialization
w2 := openvg.VGfloat(width / 2)
h2 := openvg.VGfloat(height / 2)
w := openvg.VGfloat(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
openvg.End()
bufio.NewReader(os.Stdin).ReadBytes('\n') // Pause until [RETURN]
openvg.Finish() // Graphics cleanup
}
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()
}
// 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 openvg.VGfloat, 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 []openvg.VGfloat
if needpoly {
xpoly = make([]openvg.VGfloat, nd+2)
ypoly = make([]openvg.VGfloat, 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 := openvg.VGfloat(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 := openvg.VGfloat(math.Floor(float64(miny)))
top := openvg.VGfloat(math.Ceil(float64(maxy)))
yrange := top - bot
interval := yrange / openvg.VGfloat(settings.size["yinterval"])
for yax := bot; yax <= top; yax += interval {
yaxp := fmap(yax, bot, top, openvg.VGfloat(y), openvg.VGfloat(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)
}
openvg.StrokeWidth(0)
}
// Finally, tack on the label, if specified
if len(settings.attr["label"]) > 0 {
openvg.FillColor(settings.attr["labelcolor"], 0.3)
openvg.TextMid(x+(w/2), y+(h/2), settings.attr["label"], settings.attr["font"], int(w/8)) // int(settings.size["fontsize"]))
}
openvg.StrokeWidth(0)
}
// 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 := openvg.VGfloat(height) * .95
sx := openvg.VGfloat(width) * 0.10
sy := top
sw := openvg.VGfloat(width) * .05
sh := openvg.VGfloat(height) * .045
dotsize := openvg.VGfloat(7.0)
spacing := openvg.VGfloat(2.0)
fontsize := int(openvg.VGfloat(height) * .033)
shapecolor := Color{202, 225, 255, 1.0}
openvg.Start(width, height)
openvg.FillRGB(128, 0, 0, 1)
openvg.TextEnd(openvg.VGfloat(width-20), openvg.VGfloat(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 := []openvg.VGfloat{sx, sx + (sw / 4), sx + (sw / 2), sx + ((sw * 3) / 4), sx + sw}
py := []openvg.VGfloat{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 openvg.VGfloat
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")
openvg.End()
}
// coordpoint marks a coordinate, preserving a previous color
func coordpoint(x, y, size openvg.VGfloat, c Color) {
openvg.FillRGB(128, 0, 0, 0.3)
openvg.Circle(x, y, size)
openvg.FillRGB(c.red, c.green, c.blue, c.alpha)
}