???

yaxis.go

@@ -8,8 +8,13 @@ import (
 // YAxis is a veritcal rule of the range.
 // There can be (2) y-axes; a primary and secondary.
 type YAxis struct {
-	Name           string
-	Style          Style
+	Name  string
+	Style Style
+
+	Zero GridLine
+
+	AxisType YAxisType
+
 	ValueFormatter ValueFormatter
 	Range          Range
 	Ticks          []Tick
@@ -28,31 +33,81 @@ func (ya YAxis) GetStyle() Style {
 // GetTicks returns the ticks for a series. It coalesces between user provided ticks and
 // generated ticks.
 func (ya YAxis) GetTicks(r Renderer, ra Range, vf ValueFormatter) []Tick {
+	var ticks []Tick
 	if len(ya.Ticks) > 0 {
-		return ya.Ticks
+		ticks = ya.Ticks
+	} else {
+		ticks = ya.generateTicks(r, ra, vf)
 	}
-	return ya.generateTicks(r, ra, vf)
+
+	return ticks
 }
 
 func (ya YAxis) generateTicks(r Renderer, ra Range, vf ValueFormatter) []Tick {
 	step := ya.getTickStep(r, ra, vf)
-	return GenerateTicksWithStep(ra, step, vf)
+	ticks := GenerateTicksWithStep(ra, step, vf)
+	return ticks
 }
 
 func (ya YAxis) getTickStep(r Renderer, ra Range, vf ValueFormatter) float64 {
 	tickCount := ya.getTickCount(r, ra, vf)
-	return ra.Delta() / float64(tickCount)
+	step := ra.Delta() / float64(tickCount)
+	return step
 }
 
 func (ya YAxis) getTickCount(r Renderer, ra Range, vf ValueFormatter) int {
-	textHeight := int(ya.Style.GetFontSize(DefaultFontSize))
-	height := textHeight + DefaultMinimumTickVerticalSpacing
-	count := int(math.Ceil(float64(ra.Domain) / float64(height)))
-	return count
+	return DefaultTickCount
+}
+
+// Measure returns the bounds of the axis.
+func (ya YAxis) Measure(r Renderer, canvasBox Box, ra Range, ticks []Tick) Box {
+	defaultFont, _ := GetDefaultFont()
+	r.SetFont(ya.Style.GetFont(defaultFont))
+	r.SetFontSize(ya.Style.GetFontSize(DefaultFontSize))
+
+	sort.Sort(Ticks(ticks))
+
+	var tx int
+	if ya.AxisType == YAxisPrimary {
+		tx = canvasBox.Right + DefaultYAxisMargin
+	} else if ya.AxisType == YAxisSecondary {
+		tx = canvasBox.Left - DefaultYAxisMargin
+	}
+
+	var minx, maxx, miny, maxy = math.MaxInt32, 0, math.MaxInt32, 0
+	for _, t := range ticks {
+		v := t.Value
+		ly := canvasBox.Bottom - ra.Translate(v)
+
+		tb := r.MeasureText(t.Label)
+		finalTextX := tx
+		if ya.AxisType == YAxisSecondary {
+			finalTextX = tx - tb.Width
+		}
+
+		if ya.AxisType == YAxisPrimary {
+			minx = canvasBox.Right
+			maxx = MaxInt(maxx, tx+tb.Width)
+		} else if ya.AxisType == YAxisSecondary {
+			minx = MinInt(minx, finalTextX)
+			maxx = MaxInt(maxx, tx)
+		}
+		miny = MinInt(miny, ly-tb.Height>>1)
+		maxy = MaxInt(maxy, ly+tb.Height>>1)
+	}
+
+	return Box{
+		Top:    miny,
+		Left:   minx,
+		Right:  maxx,
+		Bottom: maxy,
+		Width:  maxx - minx,
+		Height: maxy - miny,
+	}
 }
 
 // Render renders the axis.
-func (ya YAxis) Render(r Renderer, canvasBox Box, ra Range, axisType YAxisType, ticks []Tick) {
+func (ya YAxis) Render(r Renderer, canvasBox Box, ra Range, ticks []Tick) {
 	r.SetStrokeColor(ya.Style.GetStrokeColor(DefaultAxisColor))
 	r.SetStrokeWidth(ya.Style.GetStrokeWidth(DefaultAxisLineWidth))
 
@@ -65,51 +120,42 @@ func (ya YAxis) Render(r Renderer, canvasBox Box, ra Range, axisType YAxisType,
 
 	var lx int
 	var tx int
-	if axisType == YAxisPrimary {
+	if ya.AxisType == YAxisPrimary {
 		lx = canvasBox.Right
 		tx = canvasBox.Right + DefaultYAxisMargin
-
-		r.MoveTo(lx, canvasBox.Bottom)
-		r.LineTo(lx, canvasBox.Top)
-		r.Stroke()
-
-		for _, t := range ticks {
-			v := t.Value
-			ly := ra.Translate(v) + canvasBox.Top
-
-			_, pth := r.MeasureText(t.Label)
-			ty := ly + pth>>1
-
-			r.Text(t.Label, tx, ty)
-
-			r.MoveTo(lx, ly)
-			r.LineTo(lx+DefaultVerticalTickWidth, ly)
-			r.Stroke()
-		}
-	} else if axisType == YAxisSecondary {
+	} else if ya.AxisType == YAxisSecondary {
 		lx = canvasBox.Left
-
-		r.MoveTo(lx, canvasBox.Bottom)
-		r.LineTo(lx, canvasBox.Top)
-		r.Stroke()
-
-		for _, t := range ticks {
-			v := t.Value
-			ly := ra.Translate(v) + canvasBox.Top
-
-			ptw, pth := r.MeasureText(t.Label)
-
-			tw := ptw
-
-			tx = lx - (tw + DefaultYAxisMargin)
-			ty := ly + pth>>1
-
-			r.Text(t.Label, tx, ty)
-
-			r.MoveTo(lx, ly)
-			r.LineTo(lx-DefaultVerticalTickWidth, ly)
-			r.Stroke()
-		}
+		tx = canvasBox.Left - DefaultYAxisMargin
 	}
 
+	r.MoveTo(lx, canvasBox.Bottom)
+	r.LineTo(lx, canvasBox.Top)
+	r.Stroke()
+
+	for _, t := range ticks {
+		v := t.Value
+		ly := canvasBox.Bottom - ra.Translate(v)
+
+		tb := r.MeasureText(t.Label)
+
+		finalTextX := tx
+		finalTextY := ly + tb.Height>>1
+		if ya.AxisType == YAxisSecondary {
+			finalTextX = tx - tb.Width
+		}
+
+		r.Text(t.Label, finalTextX, finalTextY)
+
+		r.MoveTo(lx, ly)
+		if ya.AxisType == YAxisPrimary {
+			r.LineTo(lx+DefaultHorizontalTickWidth, ly)
+		} else if ya.AxisType == YAxisSecondary {
+			r.LineTo(lx-DefaultHorizontalTickWidth, ly)
+		}
+		r.Stroke()
+	}
+
+	if ya.Zero.Style.Show {
+		ya.Zero.Render(r, canvasBox, ra)
+	}
 }