// Plot implements the plot.Plotter interface.
func (b *BarChart) Plot(c draw.Canvas, plt *plot.Plot) {
trCat, trVal := plt.Transforms(&c)
if b.Horizontal {
trCat, trVal = trVal, trCat
}
for i, ht := range b.Values {
catVal := b.XMin + float64(i)
catMin := trCat(float64(catVal))
if !b.Horizontal {
if !c.ContainsX(catMin) {
continue
}
} else {
if !c.ContainsY(catMin) {
continue
}
}
catMin = catMin - b.Width/2 + b.Offset
catMax := catMin + b.Width
bottom := b.stackedOn.BarHeight(i)
valMin := trVal(bottom)
valMax := trVal(bottom + ht)
var pts []draw.Point
var poly []draw.Point
if !b.Horizontal {
pts = []draw.Point{
{catMin, valMin},
{catMin, valMax},
{catMax, valMax},
{catMax, valMin},
}
poly = c.ClipPolygonY(pts)
} else {
pts = []draw.Point{
{valMin, catMin},
{valMin, catMax},
{valMax, catMax},
{valMax, catMin},
}
poly = c.ClipPolygonX(pts)
}
c.FillPolygon(b.Color, poly)
var outline [][]draw.Point
if !b.Horizontal {
pts = append(pts, draw.Point{X: catMin, Y: valMin})
outline = c.ClipLinesY(pts)
} else {
pts = append(pts, draw.Point{X: valMin, Y: catMin})
outline = c.ClipLinesX(pts)
}
c.StrokeLines(b.LineStyle, outline...)
}
}