// DrawGlyph implements the Glyph interface.
func (PyramidGlyph) DrawGlyph(c *Canvas, sty GlyphStyle, pt Point) {
r := sty.Radius + (sty.Radius-sty.Radius*sinπover6)/2
var p vg.Path
p.Move(pt.X, pt.Y+r)
p.Line(pt.X-r*cosπover6, pt.Y-r*sinπover6)
p.Line(pt.X+r*cosπover6, pt.Y-r*sinπover6)
p.Close()
c.Fill(p)
}
// DrawGlyph implements the Glyph interface.
func (TriangleGlyph) DrawGlyph(c *Canvas, sty GlyphStyle, pt Point) {
c.SetLineStyle(LineStyle{Color: sty.Color, Width: vg.Points(0.5)})
r := sty.Radius + (sty.Radius-sty.Radius*sinπover6)/2
var p vg.Path
p.Move(pt.X, pt.Y+r)
p.Line(pt.X-r*cosπover6, pt.Y-r*sinπover6)
p.Line(pt.X+r*cosπover6, pt.Y-r*sinπover6)
p.Close()
c.Stroke(p)
}
// DrawGlyph implements the Glyph interface.
func (BoxGlyph) DrawGlyph(c *Canvas, sty GlyphStyle, pt Point) {
x := (sty.Radius-sty.Radius*cosπover4)/2 + sty.Radius*cosπover4
var p vg.Path
p.Move(pt.X-x, pt.Y-x)
p.Line(pt.X+x, pt.Y-x)
p.Line(pt.X+x, pt.Y+x)
p.Line(pt.X-x, pt.Y+x)
p.Close()
c.Fill(p)
}
// DrawGlyph implements the Glyph interface.
func (SquareGlyph) DrawGlyph(c *Canvas, sty GlyphStyle, pt Point) {
c.SetLineStyle(LineStyle{Color: sty.Color, Width: vg.Points(0.5)})
x := (sty.Radius-sty.Radius*cosπover4)/2 + sty.Radius*cosπover4
var p vg.Path
p.Move(pt.X-x, pt.Y-x)
p.Line(pt.X+x, pt.Y-x)
p.Line(pt.X+x, pt.Y+x)
p.Line(pt.X-x, pt.Y+x)
p.Close()
c.Stroke(p)
}
// DrawGlyph implements the Glyph interface.
func (CrossGlyph) DrawGlyph(c *Canvas, sty GlyphStyle, pt Point) {
c.SetLineStyle(LineStyle{Color: sty.Color, Width: vg.Points(0.5)})
r := sty.Radius * cosπover4
var p vg.Path
p.Move(pt.X-r, pt.Y-r)
p.Line(pt.X+r, pt.Y+r)
c.Stroke(p)
p = vg.Path{}
p.Move(pt.X-r, pt.Y+r)
p.Line(pt.X+r, pt.Y-r)
c.Stroke(p)
}
// FillPolygon fills a polygon with the given color.
func (c *Canvas) FillPolygon(clr color.Color, pts []Point) {
if len(pts) == 0 {
return
}
c.SetColor(clr)
var p vg.Path
p.Move(pts[0].X, pts[0].Y)
for _, pt := range pts[1:] {
p.Line(pt.X, pt.Y)
}
p.Close()
c.Fill(p)
}
func (c *contour) path(trX, trY func(float64) vg.Length) vg.Path {
var pa vg.Path
p := c.front()
pa.Move(trX(p.X), trY(p.Y))
for i := len(c.backward) - 2; i >= 0; i-- {
p = c.backward[i]
pa.Line(trX(p.X), trY(p.Y))
}
for _, p := range c.forward {
pa.Line(trX(p.X), trY(p.Y))
}
return pa
}
// StrokeLines draws a line connecting a set of points
// in the given Canvas.
func (c *Canvas) StrokeLines(sty LineStyle, lines ...[]Point) {
if len(lines) == 0 {
return
}
c.SetLineStyle(sty)
for _, l := range lines {
if len(l) == 0 {
continue
}
var p vg.Path
p.Move(l[0].X, l[0].Y)
for _, pt := range l[1:] {
p.Line(pt.X, pt.Y)
}
c.Stroke(p)
}
}
// Plot draws the Line, implementing the plot.Plotter
// interface.
func (pts *Line) Plot(c draw.Canvas, plt *plot.Plot) {
trX, trY := plt.Transforms(&c)
ps := make([]draw.Point, len(pts.XYs))
for i, p := range pts.XYs {
ps[i].X = trX(p.X)
ps[i].Y = trY(p.Y)
}
if pts.ShadeColor != nil && len(ps) > 0 {
c.SetColor(*pts.ShadeColor)
minY := trY(plt.Y.Min)
var pa vg.Path
pa.Move(ps[0].X, minY)
for i := range pts.XYs {
pa.Line(ps[i].X, ps[i].Y)
}
pa.Line(ps[len(pts.XYs)-1].X, minY)
pa.Close()
c.Fill(pa)
}
c.StrokeLines(pts.LineStyle, c.ClipLinesXY(ps)...)
}
// Plot implements the Plot method of the plot.Plotter interface.
func (h *HeatMap) Plot(c draw.Canvas, plt *plot.Plot) {
pal := h.Palette.Colors()
if len(pal) == 0 {
panic("heatmap: empty palette")
}
// ps scales the palette uniformly across the data range.
ps := float64(len(pal)-1) / (h.Max - h.Min)
trX, trY := plt.Transforms(&c)
var pa vg.Path
cols, rows := h.GridXYZ.Dims()
for i := 0; i < cols; i++ {
var right, left float64
switch i {
case 0:
right = (h.GridXYZ.X(i+1) - h.GridXYZ.X(i)) / 2
left = -right
case cols - 1:
right = (h.GridXYZ.X(i) - h.GridXYZ.X(i-1)) / 2
left = -right
default:
right = (h.GridXYZ.X(i+1) - h.GridXYZ.X(i)) / 2
left = -(h.GridXYZ.X(i) - h.GridXYZ.X(i-1)) / 2
}
for j := 0; j < rows; j++ {
v := h.GridXYZ.Z(i, j)
if math.IsNaN(v) || math.IsInf(v, 0) {
continue
}
pa = pa[:0]
var up, down float64
switch j {
case 0:
up = (h.GridXYZ.Y(j+1) - h.GridXYZ.Y(j)) / 2
down = -up
case rows - 1:
up = (h.GridXYZ.Y(j) - h.GridXYZ.Y(j-1)) / 2
down = -up
default:
up = (h.GridXYZ.Y(j+1) - h.GridXYZ.Y(j)) / 2
down = -(h.GridXYZ.Y(j) - h.GridXYZ.Y(j-1)) / 2
}
x, y := trX(h.GridXYZ.X(i)+left), trY(h.GridXYZ.Y(j)+down)
dx, dy := trX(h.GridXYZ.X(i)+right), trY(h.GridXYZ.Y(j)+up)
if !c.Contains(draw.Point{x, y}) || !c.Contains(draw.Point{dx, dy}) {
continue
}
pa.Move(x, y)
pa.Line(dx, y)
pa.Line(dx, dy)
pa.Line(x, dy)
pa.Close()
var col color.Color
switch {
case v < h.Min:
col = h.Underflow
case v > h.Max:
col = h.Overflow
default:
col = pal[int((v-h.Min)*ps+0.5)] // Apply palette scaling.
}
if col != nil {
c.SetColor(col)
c.Fill(pa)
}
}
}
}
// naivePlot implements the a naive rendering approach for contours.
// It is here as a debugging mode since it simply draws line segments
// generated by conrec without further computation.
func (h *Contour) naivePlot(c draw.Canvas, plt *plot.Plot) {
var pal []color.Color
if h.Palette != nil {
pal = h.Palette.Colors()
}
trX, trY := plt.Transforms(&c)
// Sort levels prior to palette scaling since we can't depend on
// sorting as a side effect from calling contourPaths.
sort.Float64s(h.Levels)
// ps is a palette scaling factor to scale the palette uniformly
// across the given levels. This enables a discordance between the
// number of colours and the number of levels.
ps := float64(len(pal)-1) / (h.Levels[len(h.Levels)-1] - h.Levels[0])
if len(h.Levels) == 1 {
ps = 0
}
levelMap := make(map[float64]int)
for i, z := range h.Levels {
levelMap[z] = i
}
// Draw each line segment as conrec generates it.
var pa vg.Path
conrec(h.GridXYZ, h.Levels, func(_, _ int, l line, z float64) {
if math.IsNaN(z) {
return
}
pa = pa[:0]
x1, y1 := trX(l.p1.X), trY(l.p1.Y)
x2, y2 := trX(l.p2.X), trY(l.p2.Y)
if !c.Contains(draw.Point{x1, y1}) || !c.Contains(draw.Point{x2, y2}) {
return
}
pa.Move(x1, y1)
pa.Line(x2, y2)
pa.Close()
style := h.LineStyles[levelMap[z]%len(h.LineStyles)]
var col color.Color
switch {
case z < h.Min:
col = h.Underflow
case z > h.Max:
col = h.Overflow
case len(pal) == 0:
col = style.Color
default:
col = pal[int((z-h.Levels[0])*ps+0.5)] // Apply palette scaling.
}
if col != nil && style.Width != 0 {
c.SetLineStyle(style)
c.SetColor(col)
c.Stroke(pa)
}
})
}