// Draw draws a plot to a draw.Canvas.
//
// Plotters are drawn in the order in which they were
// added to the plot. Plotters that implement the
// GlyphBoxer interface will have their GlyphBoxes
// taken into account when padding the plot so that
// none of their glyphs are clipped.
func (p *Plot) Draw(c draw.Canvas) {
if p.BackgroundColor != nil {
c.SetColor(p.BackgroundColor)
c.Fill(c.Rectangle.Path())
}
if p.Title.Text != "" {
c.FillText(p.Title.TextStyle, c.Center().X, c.Max.Y, -0.5, -1, p.Title.Text)
c.Max.Y -= p.Title.Height(p.Title.Text) - p.Title.Font.Extents().Descent
c.Max.Y -= p.Title.Padding
}
p.X.sanitizeRange()
x := horizontalAxis{p.X}
p.Y.sanitizeRange()
y := verticalAxis{p.Y}
ywidth := y.size()
x.draw(padX(p, draw.Crop(c, ywidth, 0, 0, 0)))
xheight := x.size()
y.draw(padY(p, draw.Crop(c, 0, 0, xheight, 0)))
dataC := padY(p, padX(p, draw.Crop(c, ywidth, 0, xheight, 0)))
for _, data := range p.plotters {
data.Plot(dataC, p)
}
p.Legend.draw(draw.Crop(draw.Crop(c, ywidth, 0, 0, 0), 0, 0, xheight, 0))
}
// 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)
}
}
}
}