package chart import ( "errors" "io" "math" "github.com/golang/freetype/truetype" ) // Chart is what we're drawing. type Chart struct { Title string TitleStyle Style Width int Height int DPI float64 Background Style Canvas Style XAxis XAxis YAxis YAxis YAxisSecondary YAxis Font *truetype.Font defaultFont *truetype.Font Series []Series Elements []Renderable } // GetDPI returns the dpi for the chart. func (c Chart) GetDPI(defaults ...float64) float64 { if c.DPI == 0 { if len(defaults) > 0 { return defaults[0] } return DefaultDPI } return c.DPI } // GetFont returns the text font. func (c Chart) GetFont() *truetype.Font { if c.Font == nil { return c.defaultFont } return c.Font } // GetWidth returns the chart width or the default value. func (c Chart) GetWidth() int { if c.Width == 0 { return DefaultChartWidth } return c.Width } // GetHeight returns the chart height or the default value. func (c Chart) GetHeight() int { if c.Height == 0 { return DefaultChartHeight } return c.Height } // Render renders the chart with the given renderer to the given io.Writer. func (c Chart) Render(rp RendererProvider, w io.Writer) error { if len(c.Series) == 0 { return errors.New("Please provide at least one series") } c.YAxisSecondary.AxisType = YAxisSecondary r, err := rp(c.GetWidth(), c.GetHeight()) if err != nil { return err } if c.Font == nil { defaultFont, err := GetDefaultFont() if err != nil { return err } c.defaultFont = defaultFont } r.SetDPI(c.GetDPI(DefaultDPI)) c.drawBackground(r) var xt, yt, yta []Tick xr, yr, yra := c.getRanges() canvasBox := c.getDefaultCanvasBox() xf, yf, yfa := c.getValueFormatters() xr, yr, yra = c.setRangeDomains(canvasBox, xr, yr, yra) err = c.checkRanges(xr, yr, yra) if err != nil { return err } if c.hasAxes() { xt, yt, yta = c.getAxesTicks(r, xr, yr, yra, xf, yf, yfa) canvasBox = c.getAxisAdjustedCanvasBox(r, canvasBox, xr, yr, yra, xt, yt, yta) xr, yr, yra = c.setRangeDomains(canvasBox, xr, yr, yra) // do a second pass in case things haven't settled yet. xt, yt, yta = c.getAxesTicks(r, xr, yr, yra, xf, yf, yfa) canvasBox = c.getAxisAdjustedCanvasBox(r, canvasBox, xr, yr, yra, xt, yt, yta) xr, yr, yra = c.setRangeDomains(canvasBox, xr, yr, yra) } if c.hasAnnotationSeries() { canvasBox = c.getAnnotationAdjustedCanvasBox(r, canvasBox, xr, yr, yra, xf, yf, yfa) xr, yr, yra = c.setRangeDomains(canvasBox, xr, yr, yra) xt, yt, yta = c.getAxesTicks(r, xr, yr, yra, xf, yf, yfa) } c.drawCanvas(r, canvasBox) c.drawAxes(r, canvasBox, xr, yr, yra, xt, yt, yta) for index, series := range c.Series { c.drawSeries(r, canvasBox, xr, yr, yra, series, index) } c.drawTitle(r) for _, a := range c.Elements { a(r, canvasBox, c.styleDefaultsElements()) } return r.Save(w) } func (c Chart) getRanges() (xrange, yrange, yrangeAlt Range) { var minx, maxx float64 = math.MaxFloat64, 0 var miny, maxy float64 = math.MaxFloat64, 0 var minya, maxya float64 = math.MaxFloat64, 0 seriesMappedToSecondaryAxis := false // note: a possible future optimization is to not scan the series values if // all axis are represented by either custom ticks or custom ranges. for _, s := range c.Series { if s.GetStyle().IsZero() || s.GetStyle().Show { seriesAxis := s.GetYAxis() if bvp, isBoundedValueProvider := s.(BoundedValueProvider); isBoundedValueProvider { seriesLength := bvp.Len() for index := 0; index < seriesLength; index++ { vx, vy1, vy2 := bvp.GetBoundedValue(index) minx = math.Min(minx, vx) maxx = math.Max(maxx, vx) if seriesAxis == YAxisPrimary { miny = math.Min(miny, vy1) miny = math.Min(miny, vy2) maxy = math.Max(maxy, vy1) maxy = math.Max(maxy, vy2) } else if seriesAxis == YAxisSecondary { minya = math.Min(minya, vy1) minya = math.Min(minya, vy2) maxya = math.Max(maxya, vy1) maxya = math.Max(maxya, vy2) seriesMappedToSecondaryAxis = true } } } else if vp, isValueProvider := s.(ValueProvider); isValueProvider { seriesLength := vp.Len() for index := 0; index < seriesLength; index++ { vx, vy := vp.GetValue(index) minx = math.Min(minx, vx) maxx = math.Max(maxx, vx) if seriesAxis == YAxisPrimary { miny = math.Min(miny, vy) maxy = math.Max(maxy, vy) } else if seriesAxis == YAxisSecondary { minya = math.Min(minya, vy) maxya = math.Max(maxya, vy) seriesMappedToSecondaryAxis = true } } } } } if c.XAxis.Range == nil { xrange = &ContinuousRange{} } else { xrange = c.XAxis.Range } if c.YAxis.Range == nil { yrange = &ContinuousRange{} } else { yrange = c.YAxis.Range } if c.YAxisSecondary.Range == nil { yrangeAlt = &ContinuousRange{} } else { yrangeAlt = c.YAxisSecondary.Range } if len(c.XAxis.Ticks) > 0 { tickMin, tickMax := math.MaxFloat64, 0.0 for _, t := range c.XAxis.Ticks { tickMin = math.Min(tickMin, t.Value) tickMax = math.Max(tickMax, t.Value) } xrange.SetMin(tickMin) xrange.SetMax(tickMax) } else if xrange.IsZero() { xrange.SetMin(minx) xrange.SetMax(maxx) } if len(c.YAxis.Ticks) > 0 { tickMin, tickMax := math.MaxFloat64, 0.0 for _, t := range c.YAxis.Ticks { tickMin = math.Min(tickMin, t.Value) tickMax = math.Max(tickMax, t.Value) } yrange.SetMin(tickMin) yrange.SetMax(tickMax) } else if yrange.IsZero() { yrange.SetMin(miny) yrange.SetMax(maxy) delta := yrange.GetDelta() roundTo := GetRoundToForDelta(delta) rmin, rmax := RoundDown(yrange.GetMin(), roundTo), RoundUp(yrange.GetMax(), roundTo) yrange.SetMin(rmin) yrange.SetMax(rmax) } if len(c.YAxisSecondary.Ticks) > 0 { tickMin, tickMax := math.MaxFloat64, 0.0 for _, t := range c.YAxis.Ticks { tickMin = math.Min(tickMin, t.Value) tickMax = math.Max(tickMax, t.Value) } yrangeAlt.SetMin(tickMin) yrangeAlt.SetMax(tickMax) } else if seriesMappedToSecondaryAxis && yrangeAlt.IsZero() { yrangeAlt.SetMin(minya) yrangeAlt.SetMax(maxya) delta := yrangeAlt.GetDelta() roundTo := GetRoundToForDelta(delta) rmin, rmax := RoundDown(yrangeAlt.GetMin(), roundTo), RoundUp(yrangeAlt.GetMax(), roundTo) yrangeAlt.SetMin(rmin) yrangeAlt.SetMax(rmax) } return } func (c Chart) checkRanges(xr, yr, yra Range) error { if math.IsInf(xr.GetDelta(), 0) || math.IsNaN(xr.GetDelta()) || xr.GetDelta() == 0 { return errors.New("Invalid (infinite or NaN) x-range delta") } if math.IsInf(yr.GetDelta(), 0) || math.IsNaN(yr.GetDelta()) || yr.GetDelta() == 0 { return errors.New("Invalid (infinite or NaN) y-range delta") } if c.hasSecondarySeries() { if math.IsInf(yra.GetDelta(), 0) || math.IsNaN(yra.GetDelta()) || yra.GetDelta() == 0 { return errors.New("Invalid (infinite or NaN) y-secondary-range delta") } } return nil } func (c Chart) getDefaultCanvasBox() Box { return c.Box() } func (c Chart) getValueFormatters() (x, y, ya ValueFormatter) { for _, s := range c.Series { if vfp, isVfp := s.(ValueFormatterProvider); isVfp { sx, sy := vfp.GetValueFormatters() if s.GetYAxis() == YAxisPrimary { x = sx y = sy } else if s.GetYAxis() == YAxisSecondary { x = sx ya = sy } } } if c.XAxis.ValueFormatter != nil { x = c.XAxis.ValueFormatter } if c.YAxis.ValueFormatter != nil { y = c.YAxis.ValueFormatter } if c.YAxisSecondary.ValueFormatter != nil { ya = c.YAxisSecondary.ValueFormatter } return } func (c Chart) hasAxes() bool { return c.XAxis.Style.Show || c.YAxis.Style.Show || c.YAxisSecondary.Style.Show } func (c Chart) getAxesTicks(r Renderer, xr, yr, yar Range, xf, yf, yfa ValueFormatter) (xticks, yticks, yticksAlt []Tick) { if c.XAxis.Style.Show { xticks = c.XAxis.GetTicks(r, xr, c.styleDefaultsAxis(), xf) } if c.YAxis.Style.Show { yticks = c.YAxis.GetTicks(r, yr, c.styleDefaultsAxis(), yf) } if c.YAxisSecondary.Style.Show { yticksAlt = c.YAxisSecondary.GetTicks(r, yar, c.styleDefaultsAxis(), yfa) } return } func (c Chart) getAxisAdjustedCanvasBox(r Renderer, canvasBox Box, xr, yr, yra Range, xticks, yticks, yticksAlt []Tick) Box { axesOuterBox := canvasBox.Clone() if c.XAxis.Style.Show { axesBounds := c.XAxis.Measure(r, canvasBox, xr, c.styleDefaultsAxis(), xticks) axesOuterBox = axesOuterBox.Grow(axesBounds) } if c.YAxis.Style.Show { axesBounds := c.YAxis.Measure(r, canvasBox, yr, c.styleDefaultsAxis(), yticks) axesOuterBox = axesOuterBox.Grow(axesBounds) } if c.YAxisSecondary.Style.Show { axesBounds := c.YAxisSecondary.Measure(r, canvasBox, yra, c.styleDefaultsAxis(), yticksAlt) axesOuterBox = axesOuterBox.Grow(axesBounds) } return canvasBox.OuterConstrain(c.Box(), axesOuterBox) } func (c Chart) setRangeDomains(canvasBox Box, xr, yr, yra Range) (Range, Range, Range) { xr.SetDomain(canvasBox.Width()) yr.SetDomain(canvasBox.Height()) yra.SetDomain(canvasBox.Height()) return xr, yr, yra } func (c Chart) hasAnnotationSeries() bool { for _, s := range c.Series { if as, isAnnotationSeries := s.(AnnotationSeries); isAnnotationSeries { if as.Style.IsZero() || as.Style.Show { return true } } } return false } func (c Chart) hasSecondarySeries() bool { for _, s := range c.Series { if s.GetYAxis() == YAxisSecondary { return true } } return false } func (c Chart) getAnnotationAdjustedCanvasBox(r Renderer, canvasBox Box, xr, yr, yra Range, xf, yf, yfa ValueFormatter) Box { annotationSeriesBox := canvasBox.Clone() for seriesIndex, s := range c.Series { if as, isAnnotationSeries := s.(AnnotationSeries); isAnnotationSeries { if as.Style.IsZero() || as.Style.Show { style := c.styleDefaultsSeries(seriesIndex) var annotationBounds Box if as.YAxis == YAxisPrimary { annotationBounds = as.Measure(r, canvasBox, xr, yr, style) } else if as.YAxis == YAxisSecondary { annotationBounds = as.Measure(r, canvasBox, xr, yra, style) } annotationSeriesBox = annotationSeriesBox.Grow(annotationBounds) } } } return canvasBox.OuterConstrain(c.Box(), annotationSeriesBox) } func (c Chart) getBackgroundStyle() Style { return c.Background.InheritFrom(c.styleDefaultsBackground()) } func (c Chart) drawBackground(r Renderer) { DrawBox(r, Box{ Right: c.GetWidth(), Bottom: c.GetHeight(), }, c.getBackgroundStyle()) } func (c Chart) getCanvasStyle() Style { return c.Canvas.InheritFrom(c.styleDefaultsCanvas()) } func (c Chart) drawCanvas(r Renderer, canvasBox Box) { DrawBox(r, canvasBox, c.getCanvasStyle()) } func (c Chart) drawAxes(r Renderer, canvasBox Box, xrange, yrange, yrangeAlt Range, xticks, yticks, yticksAlt []Tick) { if c.XAxis.Style.Show { c.XAxis.Render(r, canvasBox, xrange, c.styleDefaultsAxis(), xticks) } if c.YAxis.Style.Show { c.YAxis.Render(r, canvasBox, yrange, c.styleDefaultsAxis(), yticks) } if c.YAxisSecondary.Style.Show { c.YAxisSecondary.Render(r, canvasBox, yrangeAlt, c.styleDefaultsAxis(), yticksAlt) } } func (c Chart) drawSeries(r Renderer, canvasBox Box, xrange, yrange, yrangeAlt Range, s Series, seriesIndex int) { if s.GetStyle().IsZero() || s.GetStyle().Show { if s.GetYAxis() == YAxisPrimary { s.Render(r, canvasBox, xrange, yrange, c.styleDefaultsSeries(seriesIndex)) } else if s.GetYAxis() == YAxisSecondary { s.Render(r, canvasBox, xrange, yrangeAlt, c.styleDefaultsSeries(seriesIndex)) } } } func (c Chart) drawTitle(r Renderer) { if len(c.Title) > 0 && c.TitleStyle.Show { r.SetFont(c.TitleStyle.GetFont(c.GetFont())) r.SetFontColor(c.TitleStyle.GetFontColor(DefaultTextColor)) titleFontSize := c.TitleStyle.GetFontSize(DefaultTitleFontSize) r.SetFontSize(titleFontSize) textBox := r.MeasureText(c.Title) textWidth := textBox.Width() textHeight := textBox.Height() titleX := (c.GetWidth() >> 1) - (textWidth >> 1) titleY := c.TitleStyle.Padding.GetTop(DefaultTitleTop) + textHeight r.Text(c.Title, titleX, titleY) } } func (c Chart) styleDefaultsBackground() Style { return Style{ FillColor: DefaultBackgroundColor, StrokeColor: DefaultBackgroundStrokeColor, StrokeWidth: DefaultStrokeWidth, } } func (c Chart) styleDefaultsCanvas() Style { return Style{ FillColor: DefaultCanvasColor, StrokeColor: DefaultCanvasStrokeColor, StrokeWidth: DefaultStrokeWidth, } } func (c Chart) styleDefaultsSeries(seriesIndex int) Style { strokeColor := GetDefaultSeriesStrokeColor(seriesIndex) return Style{ StrokeColor: strokeColor, StrokeWidth: DefaultStrokeWidth, Font: c.GetFont(), FontSize: DefaultFontSize, } } func (c Chart) styleDefaultsAxis() Style { return Style{ Font: c.GetFont(), FontColor: DefaultAxisColor, FontSize: DefaultAxisFontSize, StrokeColor: DefaultAxisColor, StrokeWidth: DefaultAxisLineWidth, } } func (c Chart) styleDefaultsElements() Style { return Style{ Font: c.GetFont(), } } // Box returns the chart bounds as a box. func (c Chart) Box() Box { dpr := c.Background.Padding.GetRight(DefaultBackgroundPadding.Right) dpb := c.Background.Padding.GetBottom(DefaultBackgroundPadding.Bottom) return Box{ Top: c.Background.Padding.GetTop(DefaultBackgroundPadding.Top), Left: c.Background.Padding.GetLeft(DefaultBackgroundPadding.Left), Right: c.GetWidth() - dpr, Bottom: c.GetHeight() - dpb, } }