func (s *Sparkline) Draw(dst draw.Image) {
if len(s.data) == 0 {
return
}
min := s.data[0]
max := s.data[0]
for _, n := range s.data[1:] {
if n < min {
min = n
}
if n > max {
max = n
}
}
// try to be helpful when there's limited data
if max < 1.0 {
max = 1.0
}
if min > max-1.0 {
min = max - 1.0
if min < 0.0 {
min = 0.0
}
}
bounds := dst.Bounds()
dx, dy := bounds.Dx(), bounds.Dy()
tmp := image.NewRGBA(image.Rectangle{Max: image.Point{X: dx, Y: dy}})
p := raster.NewRGBAPainter(tmp)
r := raster.NewRasterizer(dx, dy)
r.UseNonZeroWinding = true
var q raster.Path
q.Start(s.scale(0, s.data[0], min, max, dx, dy))
for i, n := range s.data[1:] {
pt := s.scale(i+1, n, min, max, dx, dy)
q.Add1(pt)
}
const strokeWidth = fixed.Int26_6(5 << 6)
r.AddStroke(q, strokeWidth, raster.RoundCapper, raster.RoundJoiner)
p.SetColor(s.fg)
r.Rasterize(p)
r.Clear()
q.Clear()
headPt := s.scale(len(s.data)-1, s.data[len(s.data)-1], min, max, dx, dy)
q.Start(headPt)
// miniscule nudge so something actually is output
q.Add1(headPt.Add(fixed.Point26_6{X: 1, Y: 1}))
const headWidth = fixed.Int26_6(8 << 6)
r.AddStroke(q, headWidth, raster.RoundCapper, raster.RoundJoiner)
// TODO really decide between uint64 vs float32 vs uint32 etc
// value := uint64((s.data[len(s.data)-1] - min) / max * float32(^uint64(0)))
value := uint64(s.data[len(s.data)-1])
headColor := PickColor(s.thresholds, value)
p.SetColor(headColor)
r.Rasterize(p)
draw.Draw(dst, bounds, tmp, image.ZP, draw.Over)
}
func Handler(w http.ResponseWriter, req *http.Request) {
const size = 500
c := image.NewRGBA(image.Rect(0, 0, size, size))
white := &image.Uniform{C: color.White}
draw.Draw(c, c.Bounds(), white, image.ZP, draw.Src)
p := raster.NewRGBAPainter(c)
p.SetColor(color.Black)
r := raster.NewRasterizer(500, 500)
r.UseNonZeroWinding = true
var path raster.Path
path.Start(nudge(fixed.P(50, 50)))
path.Add1(nudge(fixed.P(50, 450)))
path.Add1(nudge(fixed.P(450, 450)))
r.AddStroke(path, fixed.I(2), raster.ButtCapper, raster.BevelJoiner)
r.Rasterize(p)
r.Clear()
p.SetColor(color.Gray16{0x7FFF})
path.Clear()
r.Clear()
path.Start(nudge(fixed.P(450, 450)))
path.Add1(nudge(fixed.P(450, 50)))
path.Add1(nudge(fixed.P(50, 50)))
r.AddStroke(path, fixed.I(1), raster.ButtCapper, raster.BevelJoiner)
r.Rasterize(p)
p.SetColor(color.Gray16{0x7FFF})
for x := 50; x <= 450; x += 50 {
path.Clear()
path.Start(nudge(fixed.P(x, 450)))
path.Add1(nudge(fixed.P(x, 460)))
r.AddStroke(path, fixed.I(1), raster.ButtCapper, raster.BevelJoiner)
}
for x := 50; x <= 450; x += 50 {
path.Clear()
path.Start(nudge(fixed.P(50, x)))
path.Add1(nudge(fixed.P(40, x)))
r.AddStroke(path, fixed.I(1), raster.ButtCapper, raster.BevelJoiner)
}
r.Rasterize(p)
p.SetColor(color.RGBA{0x00, 0x00, 0xFF, 0xFF})
r.Clear()
path.Clear()
path.Start(nudge(fixed.P(50, 450)))
path.Add1(nudge(fixed.P(450, 50)))
r.AddStroke(path, fixed.I(1), raster.ButtCapper, raster.BevelJoiner)
r.Rasterize(p)
p.SetColor(color.RGBA{0xCC, 0x00, 0x00, 0xFF})
r.Clear()
window := fixed.Rectangle26_6{fixed.P(50, 450), fixed.P(450, 50)}
// path = plotPath(ratSin, big.NewRat(0, 1), big.NewRat(-1, 1), big.NewRat(10, 1), big.NewRat(1, 1), window)
// path = plotPath(ratProb, big.NewRat(0, 1), big.NewRat(0, 1), big.NewRat(1, 1<<57), big.NewRat(1, 1<<57), window)
var lo, hi *big.Rat
var locap, hicap, scalecap string
id, _ := strconv.Atoi(req.FormValue("x"))
switch id {
case 0:
lo = big.NewRat(1<<53-1<<3, 1<<54)
hi = big.NewRat(1<<53+1<<3, 1<<54)
locap = "1/2 - 1/2^51"
hicap = "1/2 + 1/2^51"
scalecap = "1/2^53"
case 1:
lo = big.NewRat(1<<54-1<<4, 1<<54)
hi = big.NewRat(1<<54, 1<<54)
locap = "1 - 1/2^50"
hicap = "1"
scalecap = "1/2^53"
case 2:
lo = big.NewRat(0, 1<<54)
hi = big.NewRat(1<<4, 1<<54)
locap = "0"
hicap = "1/2^50"
scalecap = "1/2^53"
case 3:
lo = big.NewRat(0, 1<<54)
hi = big.NewRat(1<<2, 1<<62)
locap = "0"
hicap = "1/2^59"
scalecap = "1/2^63"
}
mode, _ := strconv.Atoi(req.FormValue("mode"))
path = plotPath(ratProb(mode), lo, lo, hi, hi, window)
r.AddStroke(path, fixed.I(1), raster.ButtCapper, raster.BevelJoiner)
r.Rasterize(p)
var modestr string
switch mode {
case 0:
modestr = "original behavior (can return 1)"
case 1:
modestr = "new behavior (too much 0)"
case 2:
modestr = "retry loop"
}
data, err := ioutil.ReadFile("/tmp/luxisr.ttf")
if err != nil {
panic(err)
}
tfont, err := freetype.ParseFont(data)
if err != nil {
panic(err)
}
const pt = 10
ft := freetype.NewContext()
ft.SetDst(c)
ft.SetDPI(100)
ft.SetFont(tfont)
ft.SetFontSize(float64(pt))
ft.SetSrc(image.NewUniform(color.Black))
ft.SetClip(image.Rect(0, 0, 0, 0))
wid, err := ft.DrawString(locap, freetype.Pt(0, 0))
if err != nil {
panic(err)
}
pp := freetype.Pt(50, 480)
pp.X -= wid.X / 2
ft.SetClip(c.Bounds())
ft.DrawString(locap, pp)
ft.SetClip(image.Rect(0, 0, 0, 0))
wid, err = ft.DrawString(hicap, freetype.Pt(0, 0))
if err != nil {
panic(err)
}
pp = freetype.Pt(450, 480)
pp.X -= wid.X / 2
ft.SetClip(c.Bounds())
ft.DrawString(hicap, pp)
r.Clear()
p.SetColor(color.Black)
path.Clear()
const dy = 5
path.Start(nudge(fixed.P(400, 400)))
path.Add1(nudge(fixed.P(400, 400-dy)))
path.Add1(nudge(fixed.P(400, 400+dy)))
path.Add1(nudge(fixed.P(400, 400)))
path.Add1(nudge(fixed.P(450, 400)))
path.Add1(nudge(fixed.P(450, 400-dy)))
path.Add1(nudge(fixed.P(450, 400+dy)))
path.Add1(nudge(fixed.P(450, 400)))
r.AddStroke(path, fixed.I(2), raster.ButtCapper, raster.BevelJoiner)
r.Rasterize(p)
ft.SetClip(image.Rect(0, 0, 0, 0))
wid, err = ft.DrawString(scalecap, freetype.Pt(0, 0))
if err != nil {
panic(err)
}
pp = freetype.Pt(425, 420)
pp.X -= wid.X / 2
ft.SetClip(c.Bounds())
ft.DrawString(scalecap, pp)
ft.SetClip(image.Rect(0, 0, 0, 0))
wid, err = ft.DrawString(modestr, freetype.Pt(0, 0))
if err != nil {
panic(err)
}
pp = freetype.Pt(250, 490)
pp.X -= wid.X / 2
ft.SetClip(c.Bounds())
ft.DrawString(modestr, pp)
w.Write(pngEncode(c))
}