package chart import "math" var ( // Draw contains helpers for drawing common objects. Draw = &draw{} ) type draw struct{} // LineSeries draws a line series with a renderer. func (d draw) LineSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, vs ValueProvider) { if vs.Len() == 0 { return } cb := canvasBox.Bottom cl := canvasBox.Left v0x, v0y := vs.GetValue(0) x0 := cl + xrange.Translate(v0x) y0 := cb - yrange.Translate(v0y) var vx, vy float64 var x, y int fill := style.GetFillColor() if !fill.IsZero() { r.SetFillColor(fill) r.MoveTo(x0, y0) for i := 1; i < vs.Len(); i++ { vx, vy = vs.GetValue(i) x = cl + xrange.Translate(vx) y = cb - yrange.Translate(vy) r.LineTo(x, y) } r.LineTo(x, cb) r.LineTo(x0, cb) r.Close() r.Fill() } r.SetStrokeColor(style.GetStrokeColor()) r.SetStrokeDashArray(style.GetStrokeDashArray()) r.SetStrokeWidth(style.GetStrokeWidth()) r.MoveTo(x0, y0) for i := 1; i < vs.Len(); i++ { vx, vy = vs.GetValue(i) x = cl + xrange.Translate(vx) y = cb - yrange.Translate(vy) r.LineTo(x, y) } r.Stroke() } // BoundedSeries draws a series that implements BoundedValueProvider. func (d draw) BoundedSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, bbs BoundedValueProvider, drawOffsetIndexes ...int) { drawOffsetIndex := 0 if len(drawOffsetIndexes) > 0 { drawOffsetIndex = drawOffsetIndexes[0] } style.WriteToRenderer(r) cb := canvasBox.Bottom cl := canvasBox.Left v0x, v0y1, v0y2 := bbs.GetBoundedValue(0) x0 := cl + xrange.Translate(v0x) y0 := cb - yrange.Translate(v0y1) var vx, vy1, vy2 float64 var x, y int xvalues := make([]float64, bbs.Len()) xvalues[0] = v0x y2values := make([]float64, bbs.Len()) y2values[0] = v0y2 r.MoveTo(x0, y0) for i := 1; i < bbs.Len(); i++ { vx, vy1, vy2 = bbs.GetBoundedValue(i) xvalues[i] = vx y2values[i] = vy2 x = cl + xrange.Translate(vx) y = cb - yrange.Translate(vy1) if i > drawOffsetIndex { r.LineTo(x, y) } else { r.MoveTo(x, y) } } y = cb - yrange.Translate(vy2) r.LineTo(x, y) for i := bbs.Len() - 1; i >= drawOffsetIndex; i-- { vx, vy2 = xvalues[i], y2values[i] x = cl + xrange.Translate(vx) y = cb - yrange.Translate(vy2) r.LineTo(x, y) } r.Close() r.FillStroke() } // HistogramSeries draws a value provider as boxes from 0. func (d draw) HistogramSeries(r Renderer, canvasBox Box, xrange, yrange Range, style Style, vs ValueProvider, barWidths ...int) { if vs.Len() == 0 { return } //calculate bar width? seriesLength := vs.Len() barWidth := int(math.Floor(float64(xrange.GetDomain()) / float64(seriesLength))) if len(barWidths) > 0 { barWidth = barWidths[0] } cb := canvasBox.Bottom cl := canvasBox.Left //foreach datapoint, draw a box. for index := 0; index < seriesLength; index++ { vx, vy := vs.GetValue(index) y0 := yrange.Translate(0) x := cl + xrange.Translate(vx) y := yrange.Translate(vy) d.Box(r, Box{ Top: cb - y0, Left: x - (barWidth >> 1), Right: x + (barWidth >> 1), Bottom: cb - y, }, style) } } // MeasureAnnotation measures how big an annotation would be. func (d draw) MeasureAnnotation(r Renderer, canvasBox Box, style Style, lx, ly int, label string) Box { style.WriteToRenderer(r) textBox := r.MeasureText(label) textWidth := textBox.Width() textHeight := textBox.Height() halfTextHeight := textHeight >> 1 pt := style.Padding.GetTop(DefaultAnnotationPadding.Top) pl := style.Padding.GetLeft(DefaultAnnotationPadding.Left) pr := style.Padding.GetRight(DefaultAnnotationPadding.Right) pb := style.Padding.GetBottom(DefaultAnnotationPadding.Bottom) strokeWidth := style.GetStrokeWidth() top := ly - (pt + halfTextHeight) right := lx + pl + pr + textWidth + DefaultAnnotationDeltaWidth + int(strokeWidth) bottom := ly + (pb + halfTextHeight) return Box{ Top: top, Left: lx, Right: right, Bottom: bottom, } } // Annotation draws an anotation with a renderer. func (d draw) Annotation(r Renderer, canvasBox Box, style Style, lx, ly int, label string) { style.WriteToRenderer(r) textBox := r.MeasureText(label) textWidth := textBox.Width() halfTextHeight := textBox.Height() >> 1 pt := style.Padding.GetTop(DefaultAnnotationPadding.Top) pl := style.Padding.GetLeft(DefaultAnnotationPadding.Left) pr := style.Padding.GetRight(DefaultAnnotationPadding.Right) pb := style.Padding.GetBottom(DefaultAnnotationPadding.Bottom) textX := lx + pl + DefaultAnnotationDeltaWidth textY := ly + halfTextHeight ltx := lx + DefaultAnnotationDeltaWidth lty := ly - (pt + halfTextHeight) rtx := lx + pl + pr + textWidth + DefaultAnnotationDeltaWidth rty := ly - (pt + halfTextHeight) rbx := lx + pl + pr + textWidth + DefaultAnnotationDeltaWidth rby := ly + (pb + halfTextHeight) lbx := lx + DefaultAnnotationDeltaWidth lby := ly + (pb + halfTextHeight) r.MoveTo(lx, ly) r.LineTo(ltx, lty) r.LineTo(rtx, rty) r.LineTo(rbx, rby) r.LineTo(lbx, lby) r.LineTo(lx, ly) r.Close() r.FillStroke() r.Text(label, textX, textY) } // Box draws a box with a given style. func (d draw) Box(r Renderer, b Box, s Style) { s.WriteToRenderer(r) r.MoveTo(b.Left, b.Top) r.LineTo(b.Right, b.Top) r.LineTo(b.Right, b.Bottom) r.LineTo(b.Left, b.Bottom) r.LineTo(b.Left, b.Top) r.FillStroke() } // DrawText draws text with a given style. func (d draw) Text(r Renderer, text string, x, y int, style Style) { style.GetTextOptions().WriteToRenderer(r) r.Text(text, x, y) } // TextWithin draws the text within a given box. func (d draw) TextWithin(r Renderer, text string, box Box, style Style) { lines := Text.WrapFit(r, text, box.Width(), style) linesBox := Text.MeasureLines(r, lines, style) style.GetTextOptions().WriteToRenderer(r) y := box.Top switch style.GetTextVerticalAlign() { case TextVerticalAlignBottom, TextVerticalAlignBaseline: // i have to build better baseline handling into measure text y = y - linesBox.Height() case TextVerticalAlignMiddle, TextVerticalAlignMiddleBaseline: y = (y - linesBox.Height()) >> 1 } var tx, ty int for _, line := range lines { lineBox := r.MeasureText(line) switch style.GetTextHorizontalAlign() { case TextHorizontalAlignCenter: tx = box.Left + ((lineBox.Width() - box.Left) >> 1) case TextHorizontalAlignRight: tx = box.Right - lineBox.Width() default: tx = box.Left } ty = y + lineBox.Height() d.Text(r, line, tx, ty, style) y += lineBox.Height() + style.GetTextLineSpacing() } }