histogram still needs tweaking.

histogram_series.go

@@ -0,0 +1,57 @@
+package chart
+
+// HistogramSeries is a special type of series that draws as a histogram.
+// Some peculiarities; it will always be lower bounded at 0 (at the very least).
+// This may alter ranges a bit and generally you want to put a histogram series on it's own y-axis.
+type HistogramSeries struct {
+	Name        string
+	Style       Style
+	YAxis       YAxisType
+	InnerSeries ValueProvider
+}
+
+// GetName implements Series.GetName.
+func (hs HistogramSeries) GetName() string {
+	return hs.Name
+}
+
+// GetStyle implements Series.GetStyle.
+func (hs HistogramSeries) GetStyle() Style {
+	return hs.Style
+}
+
+// GetYAxis returns which yaxis the series is mapped to.
+func (hs HistogramSeries) GetYAxis() YAxisType {
+	return hs.YAxis
+}
+
+// Len implements BoundedValueProvider.Len.
+func (hs HistogramSeries) Len() int {
+	return hs.InnerSeries.Len()
+}
+
+// GetValue implements ValueProvider.GetValue.
+func (hs HistogramSeries) GetValue(index int) (x, y float64) {
+	return hs.InnerSeries.GetValue(index)
+}
+
+// GetBoundedValue implements BoundedValueProvider.GetBoundedValue
+func (hs HistogramSeries) GetBoundedValue(index int) (x, y1, y2 float64) {
+	vx, vy := hs.InnerSeries.GetValue(index)
+
+	x = vx
+
+	if vy > 0 {
+		y1 = vy
+		return
+	}
+
+	y2 = vy
+	return
+}
+
+// Render implements Series.Render.
+func (hs HistogramSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) {
+	style := hs.Style.WithDefaultsFrom(defaults)
+	DrawHistogramSeries(r, canvasBox, xrange, yrange, style, hs)
+}