CreateLegend() returns a renderable for a legend.

This commit is contained in:
Will Charczuk 2016-07-14 19:25:40 -07:00
parent 312ebdd3df
commit 0cef99b524

View file

@ -1,5 +1,7 @@
package chart package chart
import "github.com/wcharczuk/go-chart/drawing"
// DrawLineSeries draws a line series with a renderer. // DrawLineSeries draws a line series with a renderer.
func DrawLineSeries(r Renderer, canvasBox Box, xrange, yrange Range, s Style, vs ValueProvider) { func DrawLineSeries(r Renderer, canvasBox Box, xrange, yrange Range, s Style, vs ValueProvider) {
if vs.Len() == 0 { if vs.Len() == 0 {
@ -165,3 +167,83 @@ func DrawTextCentered(r Renderer, text string, x, y int, s Style) {
ty := y - (tb.Height() >> 1) ty := y - (tb.Height() >> 1)
r.Text(text, tx, ty) r.Text(text, tx, ty)
} }
func CreateLegend(c *Chart) Renderable {
return func(r Renderer, cb Box, defaults Style) {
// DEFAULTS
legendPadding := 5
lineTextGap := 5
lineLengthMinimum := 25
var labels []string
var lines []Style
for _, s := range c.Series {
if s.GetStyle().IsZero() || s.GetStyle().Show {
if _, isAnnotationSeries := s.(AnnotationSeries); !isAnnotationSeries {
labels = append(labels, s.GetName())
lines = append(lines, s.GetStyle())
}
}
}
legend := Box{
Top: cb.Top, //padding
Left: cb.Left,
}
legendContent := Box{
Top: legend.Top + legendPadding,
Left: legend.Left + legendPadding,
}
r.SetFontColor(DefaultTextColor)
r.SetFontSize(8.0)
// measure
for x := 0; x < len(labels); x++ {
if len(labels[x]) > 0 {
tb := r.MeasureText(labels[x])
legendContent.Bottom += (tb.Height() + DefaultMinimumTickVerticalSpacing)
rowRight := tb.Width() + legendContent.Left + lineLengthMinimum + lineTextGap
legendContent.Right = MaxInt(legendContent.Right, rowRight)
}
}
legend = legend.Grow(legendContent)
DrawBox(r, legend, Style{
FillColor: drawing.ColorWhite,
StrokeColor: DefaultAxisColor,
StrokeWidth: 1.0,
})
legendContent.Right = legend.Right - legendPadding
legendContent.Bottom = legend.Bottom - legendPadding
ycursor := legendContent.Top
tx := legendContent.Left
for x := 0; x < len(labels); x++ {
if len(labels[x]) > 0 {
tb := r.MeasureText(labels[x])
ycursor += tb.Height()
//r.SetFillColor(DefaultTextColor)
r.Text(labels[x], tx, ycursor)
th2 := tb.Height() >> 1
lx := tx + tb.Width() + lineTextGap
ly := ycursor - th2
lx2 := legendContent.Right - legendPadding
r.SetStrokeColor(lines[x].GetStrokeColor())
r.SetStrokeWidth(lines[x].GetStrokeWidth())
r.SetStrokeDashArray(lines[x].GetStrokeDashArray())
r.MoveTo(lx, ly)
r.LineTo(lx2, ly)
r.Stroke()
ycursor += DefaultMinimumTickVerticalSpacing
}
}
}
}