// Plot implements the plot.Plotter interface.
func (b *BarChart) Plot(c draw.Canvas, plt *plot.Plot) {
trX, trY := plt.Transforms(&c)
for i, ht := range b.Values {
x := b.XMin + float64(i)
xmin := trX(float64(x))
if !c.ContainsX(xmin) {
continue
}
xmin = xmin - b.Width/2 + b.Offset
xmax := xmin + b.Width
bottom := b.stackedOn.BarHeight(i)
ymin := trY(bottom)
ymax := trY(bottom + ht)
pts := []draw.Point{
{xmin, ymin},
{xmin, ymax},
{xmax, ymax},
{xmax, ymin},
}
poly := c.ClipPolygonY(pts)
c.FillPolygon(b.Color, poly)
pts = append(pts, draw.Point{xmin, ymin})
outline := c.ClipLinesY(pts)
c.StrokeLines(b.LineStyle, outline...)
}
}
func (b *BarChart) Thumbnail(c *draw.Canvas) {
pts := []draw.Point{
{c.Min.X, c.Min.Y},
{c.Min.X, c.Max.Y},
{c.Max.X, c.Max.Y},
{c.Max.X, c.Min.Y},
}
poly := c.ClipPolygonY(pts)
c.FillPolygon(b.Color, poly)
pts = append(pts, draw.Point{c.Min.X, c.Min.Y})
outline := c.ClipLinesY(pts)
c.StrokeLines(b.LineStyle, outline...)
}
// Thumbnail the thumbnail for the Line,
// implementing the plot.Thumbnailer interface.
func (pts *Line) Thumbnail(c *draw.Canvas) {
if pts.ShadeColor != nil {
points := []draw.Point{
{c.Min.X, c.Min.Y},
{c.Min.X, c.Max.Y},
{c.Max.X, c.Max.Y},
{c.Max.X, c.Min.Y},
}
poly := c.ClipPolygonY(points)
c.FillPolygon(*pts.ShadeColor, poly)
points = append(points, draw.Point{c.Min.X, c.Min.Y})
} else {
y := c.Center().Y
c.StrokeLine2(pts.LineStyle, c.Min.X, y, c.Max.X, y)
}
}