Method Plot

plotter/boxplot.go:194–248

Plot draws the BoxPlot on Canvas c and Plot plt.

(c draw.Canvas, plt *plot.Plot)

// Plot draws the BoxPlot on Canvas c and Plot plt.
func (b *BoxPlot) Plot(c draw.Canvas, plt *plot.Plot) {
	if b.Horizontal {
		b := &horizBoxPlot{b}
		b.Plot(c, plt)
		return
	}

	trX, trY := plt.Transforms(&c)
	x := trX(b.Location)
	if !c.ContainsX(x) {
		return
	}
	x += b.Offset

	med := trY(b.Median)
	q1 := trY(b.Quartile1)
	q3 := trY(b.Quartile3)
	aLow := trY(b.AdjLow)
	aHigh := trY(b.AdjHigh)

	pts := []vg.Point{
		{X: x - b.Width/2, Y: q1},
		{X: x - b.Width/2, Y: q3},
		{X: x + b.Width/2, Y: q3},
		{X: x + b.Width/2, Y: q1},
		{X: x - b.Width/2 - b.BoxStyle.Width/2, Y: q1},
	}
	box := c.ClipLinesY(pts)
	if b.FillColor != nil {
		c.FillPolygon(b.FillColor, c.ClipPolygonY(pts))
	}
	c.StrokeLines(b.BoxStyle, box...)

	medLine := c.ClipLinesY([]vg.Point{
		{X: x - b.Width/2, Y: med},
		{X: x + b.Width/2, Y: med},
	})
	c.StrokeLines(b.MedianStyle, medLine...)

	cap := b.CapWidth / 2
	whisks := c.ClipLinesY(
		[]vg.Point{{X: x, Y: q3}, {X: x, Y: aHigh}},
		[]vg.Point{{X: x - cap, Y: aHigh}, {X: x + cap, Y: aHigh}},
		[]vg.Point{{X: x, Y: q1}, {X: x, Y: aLow}},
		[]vg.Point{{X: x - cap, Y: aLow}, {X: x + cap, Y: aLow}},
	)
	c.StrokeLines(b.WhiskerStyle, whisks...)

	for _, out := range b.Outside {
		y := trY(b.Value(out))
		if c.ContainsY(y) {
			c.DrawGlyphNoClip(b.GlyphStyle, vg.Point{X: x, Y: y})
		}
	}
}

// DataRange returns the minimum and maximum x
// and y values, implementing the plot.DataRanger