// Plot implements the plot.Plotter interface.
func (b *BarChart) Plot(da plot.DrawArea, plt *plot.Plot) {
	trX, trY := plt.Transforms(&da)

	for i, ht := range b.Values {
		x := b.XMin + float64(i)
		xmin := trX(float64(x))
		if !da.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 := []plot.Point{
			{xmin, ymin},
			{xmin, ymax},
			{xmax, ymax},
			{xmax, ymin},
		}
		poly := da.ClipPolygonY(pts)
		da.FillPolygon(b.Color, poly)

		pts = append(pts, plot.Pt(xmin, ymin))
		outline := da.ClipLinesY(pts)
		da.StrokeLines(b.LineStyle, outline...)
	}
}

// Plot implements the plot.Plotter interface.
func (g *Grid) Plot(da plot.DrawArea, plt *plot.Plot) {
	trX, trY := plt.Transforms(&da)

	if g.Vertical.Color == nil {
		goto horiz
	}
	for _, tk := range plt.X.Tick.Marker(plt.X.Min, plt.X.Max) {
		if tk.IsMinor() {
			continue
		}
		x := trX(tk.Value)
		da.StrokeLine2(g.Vertical, x, da.Min.Y, x, da.Min.Y+da.Size.Y)
	}

horiz:
	if g.Horizontal.Color == nil {
		return
	}
	for _, tk := range plt.Y.Tick.Marker(plt.Y.Min, plt.Y.Max) {
		if tk.IsMinor() {
			continue
		}
		y := trY(tk.Value)
		da.StrokeLine2(g.Horizontal, da.Min.X, y, da.Min.X+da.Size.X, y)
	}
}

// Plot implements the Plotter interface, drawing labels.
func (l *Labels) Plot(da plot.DrawArea, p *plot.Plot) {
	trX, trY := p.Transforms(&da)
	for i, label := range l.Labels {
		x := trX(l.XYs[i].X)
		y := trY(l.XYs[i].Y)
		if !da.Contains(plot.Pt(x, y)) {
			continue
		}
		x += l.XOffset
		y += l.YOffset
		da.FillText(l.TextStyle, x, y, l.XAlign, l.YAlign, label)
	}
}

// Plot implements the Plotter interface, drawing labels.
func (e *XErrorBars) Plot(da plot.DrawArea, p *plot.Plot) {
	trX, trY := p.Transforms(&da)
	for i, err := range e.XErrors {
		y := trY(e.XYs[i].Y)
		xlow := trX(e.XYs[i].X - math.Abs(err.Low))
		xhigh := trX(e.XYs[i].X + math.Abs(err.High))

		bar := da.ClipLinesX([]plot.Point{{xlow, y}, {xhigh, y}})
		da.StrokeLines(e.LineStyle, bar...)
		e.drawCap(&da, xlow, y)
		e.drawCap(&da, xhigh, y)
	}
}

// Plot implements the Plotter interface, drawing a line
// that connects each point in the Line.
func (h *Histogram) Plot(da plot.DrawArea, p *plot.Plot) {
	trX, trY := p.Transforms(&da)

	for _, bin := range h.Bins {
		pts := []plot.Point{
			{trX(bin.Min), trY(0)},
			{trX(bin.Max), trY(0)},
			{trX(bin.Max), trY(bin.Weight)},
			{trX(bin.Min), trY(bin.Weight)},
		}
		if h.FillColor != nil {
			da.FillPolygon(h.FillColor, da.ClipPolygonXY(pts))
		}
		pts = append(pts, plot.Pt(trX(bin.Min), trY(0)))
		da.StrokeLines(h.LineStyle, da.ClipLinesXY(pts)...)
	}
}

func (g GlyphBoxes) Plot(da plot.DrawArea, plt *plot.Plot) {
	for _, b := range plt.GlyphBoxes(plt) {
		x := da.X(b.X) + b.Rect.Min.X
		y := da.Y(b.Y) + b.Rect.Min.Y
		da.StrokeLines(g.LineStyle, []plot.Point{
			{x, y},
			{x + b.Rect.Size.X, y},
			{x + b.Rect.Size.X, y + b.Rect.Size.Y},
			{x, y + b.Rect.Size.Y},
			{x, y},
		})
	}
}

// Plot draws the Line, implementing the plot.Plotter
// interface.
func (pts *Line) Plot(da plot.DrawArea, plt *plot.Plot) {
	trX, trY := plt.Transforms(&da)
	ps := make([]plot.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 {
		da.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()
		da.Fill(pa)
	}

	da.StrokeLines(pts.LineStyle, da.ClipLinesXY(ps)...)
}

// Plot implements the Plot method of the plot.Plotter interface.
func (bs *Bubbles) Plot(da plot.DrawArea, plt *plot.Plot) {
	trX, trY := plt.Transforms(&da)

	da.SetColor(bs.Color)

	for _, d := range bs.XYZs {
		x := trX(d.X)
		y := trY(d.Y)
		if !da.Contains(plot.Pt(x, y)) {
			continue
		}

		rad := bs.radius(d.Z)

		// draw a circle centered at x, y
		var p vg.Path
		p.Move(x+rad, y)
		p.Arc(x, y, rad, 0, 2*math.Pi)
		p.Close()
		da.Fill(p)
	}
}

func (b *BoxPlot) Plot(da plot.DrawArea, plt *plot.Plot) {
	trX, trY := plt.Transforms(&da)
	x := trX(b.Location)
	if !da.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)

	box := da.ClipLinesY([]plot.Point{
		{x - b.Width/2, q1},
		{x - b.Width/2, q3},
		{x + b.Width/2, q3},
		{x + b.Width/2, q1},
		{x - b.Width/2 - b.BoxStyle.Width/2, q1},
	})
	da.StrokeLines(b.BoxStyle, box...)

	medLine := da.ClipLinesY([]plot.Point{
		{x - b.Width/2, med},
		{x + b.Width/2, med},
	})
	da.StrokeLines(b.MedianStyle, medLine...)

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

	for _, out := range b.Outside {
		y := trY(b.Value(out))
		if da.ContainsY(y) {
			da.DrawGlyphNoClip(b.GlyphStyle, plot.Pt(x, y))
		}
	}
}

func (b *QuartPlot) Plot(da plot.DrawArea, plt *plot.Plot) {
	trX, trY := plt.Transforms(&da)
	x := trX(b.Location)
	if !da.ContainsX(x) {
		return
	}
	x += b.Offset

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

	da.StrokeLine2(b.WhiskerStyle, x, aHigh, x, q3)
	if da.ContainsY(med.Y) {
		da.DrawGlyphNoClip(b.MedianStyle, med)
	}
	da.StrokeLine2(b.WhiskerStyle, x, aLow, x, q1)

	ostyle := b.MedianStyle
	ostyle.Radius = b.MedianStyle.Radius / 2
	for _, out := range b.Outside {
		y := trY(b.Value(out))
		if da.ContainsY(y) {
			da.DrawGlyphNoClip(ostyle, plot.Pt(x, y))
		}
	}
}

// drawCap draws the cap if it is not clipped.
func (e *YErrorBars) drawCap(da *plot.DrawArea, x, y vg.Length) {
	if !da.Contains(plot.Pt(x, y)) {
		return
	}
	da.StrokeLine2(e.LineStyle, x-e.CapWidth/2, y, x+e.CapWidth/2, y)
}

// Thumbnail the thumbnail for the Scatter,
// implementing the plot.Thumbnailer interface.
func (pts *Scatter) Thumbnail(da *plot.DrawArea) {
	da.DrawGlyph(pts.GlyphStyle, da.Center())
}

// Plot draws the Scatter, implementing the plot.Plotter
// interface.
func (pts *Scatter) Plot(da plot.DrawArea, plt *plot.Plot) {
	trX, trY := plt.Transforms(&da)
	for _, p := range pts.XYs {
		da.DrawGlyph(pts.GlyphStyle, plot.Pt(trX(p.X), trY(p.Y)))
	}
}

// Thumbnail the thumbnail for the Line,
// implementing the plot.Thumbnailer interface.
func (pts *Line) Thumbnail(da *plot.DrawArea) {
	if pts.ShadeColor != nil {
		points := []plot.Point{
			{da.Min.X, da.Min.Y},
			{da.Min.X, da.Max().Y},
			{da.Max().X, da.Max().Y},
			{da.Max().X, da.Min.Y},
		}
		poly := da.ClipPolygonY(points)
		da.FillPolygon(*pts.ShadeColor, poly)

		points = append(points, plot.Pt(da.Min.X, da.Min.Y))
	} else {
		y := da.Center().Y
		da.StrokeLine2(pts.LineStyle, da.Min.X, y, da.Max().X, y)
	}
}

func (b *BarChart) Thumbnail(da *plot.DrawArea) {
	pts := []plot.Point{
		{da.Min.X, da.Min.Y},
		{da.Min.X, da.Max().Y},
		{da.Max().X, da.Max().Y},
		{da.Max().X, da.Min.Y},
	}
	poly := da.ClipPolygonY(pts)
	da.FillPolygon(b.Color, poly)

	pts = append(pts, plot.Pt(da.Min.X, da.Min.Y))
	outline := da.ClipLinesY(pts)
	da.StrokeLines(b.LineStyle, outline...)
}