go-chart/first_value_annotation.go
2018-09-07 12:52:30 -07:00

38 lines
1.1 KiB
Go

package chart
import "fmt"
// FirstValueAnnotation returns an annotation series of just the first value of a value provider as an annotation.
func FirstValueAnnotation(innerSeries ValuesProvider, vfs ...ValueFormatter) AnnotationSeries {
var vf ValueFormatter
if len(vfs) > 0 {
vf = vfs[0]
} else if typed, isTyped := innerSeries.(ValueFormatterProvider); isTyped {
_, vf = typed.GetValueFormatters()
} else {
vf = FloatValueFormatter
}
var firstValue Value2
if typed, isTyped := innerSeries.(FirstValuesProvider); isTyped {
firstValue.XValue, firstValue.YValue = typed.GetFirstValues()
firstValue.Label = vf(firstValue.YValue)
} else {
firstValue.XValue, firstValue.YValue = innerSeries.GetValues(0)
firstValue.Label = vf(firstValue.YValue)
}
var seriesName string
var seriesStyle Style
if typed, isTyped := innerSeries.(Series); isTyped {
seriesName = fmt.Sprintf("%s - First Value", typed.GetName())
seriesStyle = typed.GetStyle()
}
return AnnotationSeries{
Name: seriesName,
Style: seriesStyle,
Annotations: []Value2{firstValue},
}
}