go-chart/drawing_helpers.go
Will Charczuk e9a36274ac snapshot.
2016-07-10 01:11:47 -07:00

96 lines
2.3 KiB
Go

package chart
import "math"
// DrawLineSeries draws a line series with a renderer.
func DrawLineSeries(r Renderer, canvasBox Box, xrange, yrange Range, s Style, vs ValueProvider) {
if vs.Len() == 0 {
return
}
cx := canvasBox.Left
cy := canvasBox.Top
cb := canvasBox.Bottom
cw := canvasBox.Width
v0x, v0y := vs.GetValue(0)
x0 := cw - xrange.Translate(v0x)
y0 := yrange.Translate(v0y)
var vx, vy float64
var x, y int
fill := s.GetFillColor()
if !fill.IsZero() {
r.SetFillColor(fill)
r.MoveTo(x0+cx, y0+cy)
for i := 1; i < vs.Len(); i++ {
vx, vy = vs.GetValue(i)
x = cw - xrange.Translate(vx)
y = yrange.Translate(vy)
r.LineTo(x+cx, y+cy)
}
r.LineTo(x+cx, cb)
r.LineTo(x0+cx, cb)
r.Close()
r.Fill()
}
stroke := s.GetStrokeColor()
r.SetStrokeColor(stroke)
r.SetStrokeWidth(s.GetStrokeWidth(DefaultStrokeWidth))
r.MoveTo(x0+cx, y0+cy)
for i := 1; i < vs.Len(); i++ {
vx, vy = vs.GetValue(i)
x = cw - xrange.Translate(vx)
y = yrange.Translate(vy)
r.LineTo(x+cx, y+cy)
}
r.Stroke()
}
// DrawAnnotation draws an anotation with a renderer.
func DrawAnnotation(r Renderer, canvasBox Box, xrange, yrange Range, s Style, lx, ly int, label string) {
r.SetFontSize(s.GetFontSize(DefaultAnnotationFontSize))
textWidth, _ := r.MeasureText(label)
textHeight := int(math.Floor(DefaultAnnotationFontSize))
halfTextHeight := textHeight >> 1
pt := s.Padding.GetTop(DefaultAnnotationPadding.Top)
pl := s.Padding.GetLeft(DefaultAnnotationPadding.Left)
pr := s.Padding.GetRight(DefaultAnnotationPadding.Right)
pb := s.Padding.GetBottom(DefaultAnnotationPadding.Bottom)
textX := lx + pl + DefaultAnnotationDeltaWidth
textY := ly + halfTextHeight
ltlx := lx + pl + DefaultAnnotationDeltaWidth
ltly := ly - (pt + halfTextHeight)
ltrx := lx + pl + pr + textWidth
ltry := ly - (pt + halfTextHeight)
lbrx := lx + pl + pr + textWidth
lbry := ly + (pb + halfTextHeight)
lblx := lx + DefaultAnnotationDeltaWidth
lbly := ly + (pb + halfTextHeight)
//draw the shape...
r.SetFillColor(s.GetFillColor(DefaultAnnotationFillColor))
r.SetStrokeColor(s.GetStrokeColor())
r.SetStrokeWidth(s.GetStrokeWidth())
r.MoveTo(lx, ly)
r.LineTo(ltlx, ltly)
r.LineTo(ltrx, ltry)
r.LineTo(lbrx, lbry)
r.LineTo(lblx, lbly)
r.LineTo(lx, ly)
r.Close()
r.FillStroke()
r.SetFontColor(s.GetFontColor(DefaultTextColor))
r.Text(label, textX, textY)
}