package chart import ( "errors" "io" "github.com/golang/freetype/truetype" "github.com/wcharczuk/go-chart/drawing" ) // 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 Series []Series } // 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, error) { if c.Font == nil { f, err := GetDefaultFont() if err != nil { return nil, err } return f, nil } return c.Font, nil } // 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") } r, err := rp(c.Width, c.Height) if err != nil { return err } font, err := c.GetFont() if err != nil { return err } c.Font = font r.SetFont(font) r.SetDPI(c.GetDPI(DefaultDPI)) xrange, yrange, yrangeAlt := c.getRanges() canvasBox := c.getDefaultCanvasBox() xf, yf, yfa := c.getValueFormatters() xrange, yrange, yrangeAlt = c.setRangeDomains(canvasBox, xrange, yrange, yrangeAlt) xticks, yticks, yticksAlt := c.getAxesTicks(r, xrange, yrange, yrangeAlt, xf, yf, yfa) canvasBox = c.getAdjustedCanvasBox(r, canvasBox, xticks, yticks, yticksAlt) // we do a second pass to take the updated domains into account xrange, yrange, yrangeAlt = c.setRangeDomains(canvasBox, xrange, yrange, yrangeAlt) xticks, yticks, yticksAlt = c.getAxesTicks(r, xrange, yrange, yrangeAlt, xf, yf, yfa) canvasBox = c.getAdjustedCanvasBox(r, canvasBox, xticks, yticks, yticksAlt) c.drawBackground(r) c.drawCanvas(r, canvasBox) c.drawAxes(r, canvasBox, xrange, yrange, yrangeAlt, xticks, yticks, yticksAlt) for index, series := range c.Series { c.drawSeries(r, canvasBox, xrange, yrange, yrangeAlt, series, index) } c.drawTitle(r) return r.Save(w) } func (c Chart) getRanges() (xrange, yrange, yrangeAlt Range) { //iterate over each series, pull out the min/max for x,y var didSetFirstValues bool var globalMinX, globalMaxX float64 var globalMinY, globalMaxY float64 var globalMinYA, globalMaxYA float64 for _, s := range c.Series { if vp, isValueProvider := s.(ValueProvider); isValueProvider { seriesLength := vp.Len() for index := 0; index < seriesLength; index++ { vx, vy := vp.GetValue(index) if didSetFirstValues { if globalMinX > vx { globalMinX = vx } if globalMaxX < vx { globalMaxX = vx } if s.GetYAxis() == YAxisPrimary { if globalMinY > vy { globalMinY = vy } if globalMaxY < vy { globalMaxY = vy } } else if s.GetYAxis() == YAxisSecondary { if globalMinYA > vy { globalMinYA = vy } if globalMaxYA < vy { globalMaxYA = vy } } } else { globalMinX, globalMaxX = vx, vx if s.GetYAxis() == YAxisPrimary { globalMinY, globalMaxY = vy, vy } else if s.GetYAxis() == YAxisSecondary { globalMinYA, globalMaxYA = vy, vy } didSetFirstValues = true } } } } if !c.XAxis.Range.IsZero() { xrange.Min = c.XAxis.Range.Min xrange.Max = c.XAxis.Range.Max } else { xrange.Min = globalMinX xrange.Max = globalMaxX } if !c.YAxis.Range.IsZero() { yrange.Min = c.YAxis.Range.Min yrange.Max = c.YAxis.Range.Max } else { yrange.Min = globalMinY yrange.Max = globalMaxY } return } func (c Chart) getDefaultCanvasBox() Box { dpl := c.Background.Padding.GetLeft(DefaultBackgroundPadding.Left) dpr := c.Background.Padding.GetRight(DefaultBackgroundPadding.Right) dpb := c.Background.Padding.GetBottom(DefaultBackgroundPadding.Bottom) cb := Box{ Top: c.Background.Padding.GetTop(DefaultBackgroundPadding.Top), Left: dpl, Right: c.Width - dpr, Bottom: c.Height - dpb, } cb.Height = cb.Bottom - cb.Top cb.Width = cb.Right - cb.Left return cb } 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) 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, xf) } if c.YAxis.Style.Show { yticks = c.YAxis.GetTicks(r, yr, yf) } if c.YAxisSecondary.Style.Show { yticksAlt = c.YAxisSecondary.GetTicks(r, yr, yf) } return } func (c Chart) getAdjustedCanvasBox(r Renderer, defaults Box, xticks, yticks, yticksAlt []Tick) Box { canvasBox := Box{} var dpl, dpr, dpb int if c.XAxis.Style.Show { dpb = c.getXAxisHeight(r, xticks) } if c.YAxis.Style.Show { dpr = c.getYAxisWidth(r, yticks) } if c.YAxisSecondary.Style.Show { dpl = c.getYAxisSecondaryWidth(r, yticksAlt) } canvasBox.Top = defaults.Top if dpl != 0 { canvasBox.Left = c.Canvas.Padding.GetLeft(dpl) } else { canvasBox.Left = defaults.Left } if dpr != 0 { canvasBox.Right = c.Width - c.Canvas.Padding.GetRight(dpr) } else { canvasBox.Right = defaults.Right } if dpb != 0 { canvasBox.Bottom = c.Height - c.Canvas.Padding.GetBottom(dpb) } else { canvasBox.Bottom = defaults.Bottom } canvasBox.Width = canvasBox.Right - canvasBox.Left canvasBox.Height = canvasBox.Bottom - canvasBox.Top return canvasBox } func (c Chart) getXAxisHeight(r Renderer, ticks []Tick) int { r.SetFontSize(c.XAxis.Style.GetFontSize(DefaultFontSize)) r.SetFont(c.XAxis.Style.GetFont(c.Font)) var tl int for _, t := range ticks { _, lh := r.MeasureText(t.Label) if lh > tl { tl = lh } } return tl + DefaultXAxisMargin } func (c Chart) getYAxisWidth(r Renderer, ticks []Tick) int { var ll string for _, t := range ticks { if len(t.Label) > len(ll) { ll = t.Label } } r.SetFontSize(c.YAxis.Style.GetFontSize(DefaultFontSize)) r.SetFont(c.YAxis.Style.GetFont(c.Font)) tw, _ := r.MeasureText(ll) return tw + DefaultYAxisMargin } func (c Chart) getYAxisSecondaryWidth(r Renderer, ticks []Tick) int { var ll string for _, t := range ticks { if len(t.Label) > len(ll) { ll = t.Label } } r.SetFontSize(c.YAxisSecondary.Style.GetFontSize(DefaultFontSize)) r.SetFont(c.YAxisSecondary.Style.GetFont(c.Font)) tw, _ := r.MeasureText(ll) return tw + DefaultYAxisMargin } func (c Chart) setRangeDomains(canvasBox Box, xrange, yrange, yrangeAlt Range) (Range, Range, Range) { xrange.Domain = canvasBox.Width yrange.Domain = canvasBox.Height yrangeAlt.Domain = canvasBox.Height return xrange, yrange, yrangeAlt } func (c Chart) drawBackground(r Renderer) { r.SetFillColor(c.Background.GetFillColor(DefaultBackgroundColor)) r.SetStrokeColor(c.Background.GetStrokeColor(DefaultBackgroundStrokeColor)) r.SetStrokeWidth(c.Background.GetStrokeWidth(DefaultStrokeWidth)) r.MoveTo(0, 0) r.LineTo(c.Width, 0) r.LineTo(c.Width, c.Height) r.LineTo(0, c.Height) r.LineTo(0, 0) r.Close() r.FillStroke() } func (c Chart) drawCanvas(r Renderer, canvasBox Box) { r.SetFillColor(c.Canvas.GetFillColor(DefaultCanvasColor)) r.SetStrokeColor(c.Canvas.GetStrokeColor(DefaultCanvasStrokColor)) r.SetStrokeWidth(c.Canvas.GetStrokeWidth(DefaultStrokeWidth)) r.MoveTo(canvasBox.Left, canvasBox.Top) r.LineTo(canvasBox.Right, canvasBox.Top) r.LineTo(canvasBox.Right, canvasBox.Bottom) r.LineTo(canvasBox.Left, canvasBox.Bottom) r.LineTo(canvasBox.Left, canvasBox.Top) r.Close() r.FillStroke() } 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, xticks) } if c.YAxis.Style.Show { c.YAxis.Render(r, canvasBox, yrange, YAxisPrimary, yticks) } if c.YAxisSecondary.Style.Show { c.YAxisSecondary.Render(r, canvasBox, yrangeAlt, YAxisSecondary, yticksAlt) } } func (c Chart) getSeriesStyleDefaults(seriesIndex int) Style { strokeColor := GetDefaultSeriesStrokeColor(seriesIndex) return Style{ StrokeColor: strokeColor, StrokeWidth: DefaultStrokeWidth, FillColor: strokeColor.WithAlpha(100), Font: c.Font, FontSize: DefaultFontSize, } } func (c Chart) drawSeries(r Renderer, canvasBox Box, xrange, yrange, yrangeAlt Range, s Series, seriesIndex int) { if s.GetYAxis() == YAxisPrimary { s.Render(r, canvasBox, xrange, yrange, c.getSeriesStyleDefaults(seriesIndex)) } else if s.GetYAxis() == YAxisSecondary { s.Render(r, canvasBox, xrange, yrange, c.getSeriesStyleDefaults(seriesIndex)) } } func (c Chart) drawTitle(r Renderer) { if len(c.Title) > 0 && c.TitleStyle.Show { r.SetFont(c.TitleStyle.GetFont(c.Font)) r.SetFontColor(c.TitleStyle.GetFontColor(DefaultTextColor)) titleFontSize := c.TitleStyle.GetFontSize(DefaultTitleFontSize) r.SetFontSize(titleFontSize) textWidthPoints, textHeightPoints := r.MeasureText(c.Title) textWidth := int(drawing.PointsToPixels(r.GetDPI(), float64(textWidthPoints))) textHeight := int(drawing.PointsToPixels(r.GetDPI(), float64(textHeightPoints))) titleX := (c.Width >> 1) - (textWidth >> 1) titleY := c.TitleStyle.Padding.GetTop(DefaultTitleTop) + textHeight r.Text(c.Title, titleX, titleY) } }