go-chart/util.go
2016-07-08 17:57:14 -07:00

73 lines
1.4 KiB
Go

package chart
import (
"fmt"
"image/color"
"time"
)
// ColorIsZero returns if a color.RGBA is unset or not.
func ColorIsZero(c color.RGBA) bool {
return c.R == 0 && c.G == 0 && c.B == 0 && c.A == 0
}
// ColorAsString returns if a color.RGBA is unset or not.
func ColorAsString(c color.RGBA) string {
a := float64(c.A) / float64(255)
return fmt.Sprintf("rgba(%v,%v,%v,%.1f)", c.R, c.G, c.B, a)
}
// MinAndMax returns both the min and max in one pass.
func MinAndMax(values ...float64) (min float64, max float64) {
if len(values) == 0 {
return
}
min = values[0]
max = values[0]
for _, v := range values {
if max < v {
max = v
}
if min > v {
min = v
}
}
return
}
// MinAndMaxOfTime returns the min and max of a given set of times
// in one pass.
func MinAndMaxOfTime(values ...time.Time) (min time.Time, max time.Time) {
if len(values) == 0 {
return
}
min = values[0]
max = values[0]
for _, v := range values {
if max.Before(v) {
max = v
}
if min.After(v) {
min = v
}
}
return
}
// Slices generates N slices that span the total.
// The resulting array will be intermediate indexes until total.
func Slices(count int, total float64) []float64 {
var values []float64
sliceWidth := float64(total) / float64(count)
for cursor := 0.0; cursor < total; cursor += sliceWidth {
values = append(values, cursor)
}
return values
}
func flf(v float64) string {
return fmt.Sprintf("%.2f", v)
}