go-chart/yaxis.go
2016-07-12 16:47:52 -07:00

163 lines
3.7 KiB
Go

package chart
import (
"math"
"sort"
)
// YAxis is a veritcal rule of the range.
// There can be (2) y-axes; a primary and secondary.
type YAxis struct {
Name string
Style Style
Zero GridLine
AxisType YAxisType
ValueFormatter ValueFormatter
Range Range
Ticks []Tick
}
// GetName returns the name.
func (ya YAxis) GetName() string {
return ya.Name
}
// GetStyle returns the style.
func (ya YAxis) GetStyle() Style {
return ya.Style
}
// GetTicks returns the ticks for a series. It coalesces between user provided ticks and
// generated ticks.
func (ya YAxis) GetTicks(r Renderer, ra Range, vf ValueFormatter) []Tick {
var ticks []Tick
if len(ya.Ticks) > 0 {
ticks = ya.Ticks
} else {
ticks = ya.generateTicks(r, ra, vf)
}
return ticks
}
func (ya YAxis) generateTicks(r Renderer, ra Range, vf ValueFormatter) []Tick {
step := ya.getTickStep(r, ra, vf)
ticks := GenerateTicksWithStep(ra, step, vf)
return ticks
}
func (ya YAxis) getTickStep(r Renderer, ra Range, vf ValueFormatter) float64 {
tickCount := ya.getTickCount(r, ra, vf)
step := ra.Delta() / float64(tickCount)
return step
}
func (ya YAxis) getTickCount(r Renderer, ra Range, vf ValueFormatter) int {
//given the domain, figure out how many ticks we can draw ...
label := vf(ra.Min)
tb := r.MeasureText(label)
return int(math.Ceil(float64(ra.Domain) / float64(tb.Height()+DefaultMinimumTickVerticalSpacing)))
}
// Measure returns the bounds of the axis.
func (ya YAxis) Measure(r Renderer, canvasBox Box, ra Range, ticks []Tick) Box {
defaultFont, _ := GetDefaultFont()
r.SetFont(ya.Style.GetFont(defaultFont))
r.SetFontSize(ya.Style.GetFontSize(DefaultFontSize))
sort.Sort(Ticks(ticks))
var tx int
if ya.AxisType == YAxisPrimary {
tx = canvasBox.Right + DefaultYAxisMargin
} else if ya.AxisType == YAxisSecondary {
tx = canvasBox.Left - DefaultYAxisMargin
}
var minx, maxx, miny, maxy = math.MaxInt32, 0, math.MaxInt32, 0
for _, t := range ticks {
v := t.Value
ly := canvasBox.Bottom - ra.Translate(v)
tb := r.MeasureText(t.Label)
finalTextX := tx
if ya.AxisType == YAxisSecondary {
finalTextX = tx - tb.Width()
}
if ya.AxisType == YAxisPrimary {
minx = canvasBox.Right
maxx = MaxInt(maxx, tx+tb.Width())
} else if ya.AxisType == YAxisSecondary {
minx = MinInt(minx, finalTextX)
maxx = MaxInt(maxx, tx)
}
miny = MinInt(miny, ly-tb.Height()>>1)
maxy = MaxInt(maxy, ly+tb.Height()>>1)
}
return Box{
Top: miny,
Left: minx,
Right: maxx,
Bottom: maxy,
}
}
// Render renders the axis.
func (ya YAxis) Render(r Renderer, canvasBox Box, ra Range, ticks []Tick) {
r.SetStrokeColor(ya.Style.GetStrokeColor(DefaultAxisColor))
r.SetStrokeWidth(ya.Style.GetStrokeWidth(DefaultAxisLineWidth))
fontColor := ya.Style.GetFontColor(DefaultAxisColor)
r.SetFontColor(fontColor)
fontSize := ya.Style.GetFontSize(DefaultFontSize)
r.SetFontSize(fontSize)
sort.Sort(Ticks(ticks))
var lx int
var tx int
if ya.AxisType == YAxisPrimary {
lx = canvasBox.Right
tx = lx + DefaultYAxisMargin
} else if ya.AxisType == YAxisSecondary {
lx = canvasBox.Left
tx = lx - DefaultYAxisMargin
}
r.MoveTo(lx, canvasBox.Bottom)
r.LineTo(lx, canvasBox.Top)
r.Stroke()
for _, t := range ticks {
v := t.Value
ly := canvasBox.Bottom - ra.Translate(v)
tb := r.MeasureText(t.Label)
finalTextX := tx
finalTextY := ly + tb.Height()>>1
if ya.AxisType == YAxisSecondary {
finalTextX = tx - tb.Width()
}
r.Text(t.Label, finalTextX, finalTextY)
r.MoveTo(lx, ly)
if ya.AxisType == YAxisPrimary {
r.LineTo(lx+DefaultHorizontalTickWidth, ly)
} else if ya.AxisType == YAxisSecondary {
r.LineTo(lx-DefaultHorizontalTickWidth, ly)
}
r.Stroke()
}
if ya.Zero.Style.Show {
ya.Zero.Render(r, canvasBox, ra)
}
}