package chart import ( "io" "math" "github.com/golang/freetype/truetype" ) // Chart is what we're drawing. type Chart struct { Title string TitleStyle Style Width int Height int Background Style Canvas Style Axes Style FinalValueLabel Style XRange Range YRange Range Font *truetype.Font Series []Series } // GetFont returns the text font. func (c Chart) GetFont() (*truetype.Font, error) { if c.Font != nil { return c.Font, nil } return GetDefaultFont() } // Render renders the chart with the given renderer to the given io.Writer. func (c *Chart) Render(provider RendererProvider, w io.Writer) error { r := provider(c.Width, c.Height) if c.hasText() { font, err := c.GetFont() if err != nil { return err } r.SetFont(font) } canvasBox := c.calculateCanvasBox(r) xrange, yrange := c.initRanges(canvasBox) c.drawBackground(r) c.drawCanvas(r, canvasBox) c.drawAxes(r, canvasBox, xrange, yrange) for index, series := range c.Series { c.drawSeries(r, canvasBox, index, series, xrange, yrange) } c.drawTitle(r) return r.Save(w) } func (c Chart) hasText() bool { return c.TitleStyle.Show || c.Axes.Show } func (c Chart) calculateCanvasBox(r Renderer) Box { dpr := DefaultBackgroundPadding.Right finalLabelWidth := c.calculateFinalLabelWidth(r) if finalLabelWidth > dpr { dpr = finalLabelWidth } dpb := DefaultBackgroundPadding.Bottom cb := Box{ Top: c.Background.Padding.GetTop(DefaultBackgroundPadding.Top), Left: c.Background.Padding.GetLeft(DefaultBackgroundPadding.Left), Right: c.Width - c.Background.Padding.GetRight(dpr), Bottom: c.Height - c.Background.Padding.GetBottom(dpb), } cb.Height = cb.Bottom - cb.Top cb.Width = cb.Right - cb.Left return cb } func (c Chart) calculateFinalLabelWidth(r Renderer) int { if !c.FinalValueLabel.Show { return 0 } var finalLabelText string for _, s := range c.Series { _, ll := s.GetLabel(s.Len() - 1) if len(finalLabelText) < len(ll) { finalLabelText = ll } } r.SetFontSize(c.FinalValueLabel.GetFontSize(DefaultFinalLabelFontSize)) textWidth := r.MeasureText(finalLabelText) pl := c.FinalValueLabel.Padding.GetLeft(DefaultFinalLabelPadding.Left) pr := c.FinalValueLabel.Padding.GetRight(DefaultFinalLabelPadding.Right) asw := int(c.Axes.GetStrokeWidth(DefaultAxisLineWidth)) lsw := int(c.FinalValueLabel.GetStrokeWidth(DefaultAxisLineWidth)) return DefaultFinalLabelDeltaWidth + pl + pr + textWidth + asw + 2*lsw } func (c Chart) initRanges(canvasBox Box) (xrange Range, yrange Range) { //iterate over each series, pull out the min/max for x,y var didSetFirstValues bool var globalMinY, globalMinX float64 var globalMaxY, globalMaxX float64 for _, s := range c.Series { seriesLength := s.Len() for index := 0; index < seriesLength; index++ { vx, vy := s.GetValue(index) if didSetFirstValues { if globalMinX > vx { globalMinX = vx } if globalMinY > vy { globalMinY = vy } if globalMaxX < vx { globalMaxX = vx } if globalMaxY < vy { globalMaxY = vy } } else { globalMinX, globalMaxX = vx, vx globalMinY, globalMaxY = vy, vy didSetFirstValues = true } } } if c.XRange.IsZero() { xrange.Min = globalMinX xrange.Max = globalMaxX } else { xrange.Min = c.XRange.Min xrange.Max = c.XRange.Max } xrange.Domain = canvasBox.Width if c.YRange.IsZero() { yrange.Min = globalMinY yrange.Max = globalMaxY } else { yrange.Min = c.YRange.Min yrange.Max = c.YRange.Max } yrange.Domain = canvasBox.Height return } func (c Chart) drawBackground(r Renderer) { r.SetFillColor(c.Background.GetFillColor(DefaultBackgroundColor)) r.SetStrokeColor(c.Background.GetStrokeColor(DefaultBackgroundStrokeColor)) r.SetLineWidth(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.SetLineWidth(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 Range) { if c.Axes.Show { r.SetStrokeColor(c.Axes.GetStrokeColor(DefaultAxisColor)) r.SetLineWidth(c.Axes.GetStrokeWidth(DefaultStrokeWidth)) r.MoveTo(canvasBox.Left, canvasBox.Bottom) r.LineTo(canvasBox.Right, canvasBox.Bottom) r.LineTo(canvasBox.Right, canvasBox.Top) r.Stroke() c.drawAxesLabels(r, xrange, yrange) } } func (c Chart) drawAxesLabels(r Renderer, xrange, yrange Range) { // do x axis // do y axis } func (c Chart) drawSeries(r Renderer, canvasBox Box, index int, s Series, xrange, yrange Range) { r.SetStrokeColor(s.GetStyle().GetStrokeColor(GetDefaultSeriesStrokeColor(index))) r.SetLineWidth(s.GetStyle().GetStrokeWidth(DefaultStrokeWidth)) if s.Len() == 0 { return } cx := canvasBox.Left cy := canvasBox.Top cw := canvasBox.Width v0x, v0y := s.GetValue(0) x0 := cw - xrange.Translate(v0x) y0 := yrange.Translate(v0y) r.MoveTo(x0+cx, y0+cy) var vx, vy float64 var x, y int for i := 1; i < s.Len(); i++ { vx, vy = s.GetValue(i) x = cw - xrange.Translate(vx) y = yrange.Translate(vy) r.LineTo(x+cx, y+cy) } r.Stroke() c.drawFinalValueLabel(r, canvasBox, index, s, yrange) } func (c Chart) drawFinalValueLabel(r Renderer, canvasBox Box, index int, s Series, yrange Range) { if c.FinalValueLabel.Show { _, lv := s.GetValue(s.Len() - 1) _, ll := s.GetLabel(s.Len() - 1) py := canvasBox.Top ly := yrange.Translate(lv) + py r.SetFontSize(c.FinalValueLabel.GetFontSize(DefaultFinalLabelFontSize)) textWidth := r.MeasureText(ll) textHeight := int(math.Floor(DefaultFinalLabelFontSize)) halfTextHeight := textHeight >> 1 cx := canvasBox.Right + int(c.Axes.GetStrokeWidth(DefaultAxisLineWidth)) pt := c.FinalValueLabel.Padding.GetTop(DefaultFinalLabelPadding.Top) pl := c.FinalValueLabel.Padding.GetLeft(DefaultFinalLabelPadding.Left) pr := c.FinalValueLabel.Padding.GetRight(DefaultFinalLabelPadding.Right) pb := c.FinalValueLabel.Padding.GetBottom(DefaultFinalLabelPadding.Bottom) textX := cx + pl + DefaultFinalLabelDeltaWidth textY := ly + halfTextHeight ltlx := cx + pl + DefaultFinalLabelDeltaWidth ltly := ly - (pt + halfTextHeight) ltrx := cx + pl + pr + textWidth ltry := ly - (pt + halfTextHeight) lbrx := cx + pl + pr + textWidth lbry := ly + (pb + halfTextHeight) lblx := cx + DefaultFinalLabelDeltaWidth lbly := ly + (pb + halfTextHeight) //draw the shape... r.SetFillColor(c.FinalValueLabel.GetFillColor(DefaultFinalLabelBackgroundColor)) r.SetStrokeColor(c.FinalValueLabel.GetStrokeColor(s.GetStyle().GetStrokeColor(GetDefaultSeriesStrokeColor(index)))) r.SetLineWidth(c.FinalValueLabel.GetStrokeWidth(DefaultAxisLineWidth)) r.MoveTo(cx, ly) r.LineTo(ltlx, ltly) r.LineTo(ltrx, ltry) r.LineTo(lbrx, lbry) r.LineTo(lblx, lbly) r.LineTo(cx, ly) r.Close() r.FillStroke() r.SetFontColor(c.FinalValueLabel.GetFontColor(DefaultTextColor)) r.Text(ll, textX, textY) } } func (c Chart) drawTitle(r Renderer) error { if len(c.Title) > 0 && c.TitleStyle.Show { r.SetFontColor(c.Canvas.GetFontColor(DefaultTextColor)) titleFontSize := c.Canvas.GetFontSize(DefaultTitleFontSize) r.SetFontSize(titleFontSize) textWidth := r.MeasureText(c.Title) titleX := (c.Width >> 1) - (textWidth >> 1) titleY := c.TitleStyle.Padding.GetTop(DefaultTitleTop) + int(titleFontSize) r.Text(c.Title, titleX, titleY) } return nil }