go-chart/value_formatter.go
twessling-icas 1ccfbb0172
add logarithmic axes support, with tests. Supports positive Y-values only. (#141)
Co-authored-by: Ton Wessling <twessling@ebay.com>
2023-05-22 08:37:57 -07:00

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package chart
import (
"fmt"
"strconv"
"time"
)
// ValueFormatter is a function that takes a value and produces a string.
type ValueFormatter func(v interface{}) string
// TimeValueFormatter is a ValueFormatter for timestamps.
func TimeValueFormatter(v interface{}) string {
return formatTime(v, DefaultDateFormat)
}
// TimeHourValueFormatter is a ValueFormatter for timestamps.
func TimeHourValueFormatter(v interface{}) string {
return formatTime(v, DefaultDateHourFormat)
}
// TimeMinuteValueFormatter is a ValueFormatter for timestamps.
func TimeMinuteValueFormatter(v interface{}) string {
return formatTime(v, DefaultDateMinuteFormat)
}
// TimeDateValueFormatter is a ValueFormatter for timestamps.
func TimeDateValueFormatter(v interface{}) string {
return formatTime(v, "2006-01-02")
}
// TimeValueFormatterWithFormat returns a time formatter with a given format.
func TimeValueFormatterWithFormat(format string) ValueFormatter {
return func(v interface{}) string {
return formatTime(v, format)
}
}
// TimeValueFormatterWithFormat is a ValueFormatter for timestamps with a given format.
func formatTime(v interface{}, dateFormat string) string {
if typed, isTyped := v.(time.Time); isTyped {
return typed.Format(dateFormat)
}
if typed, isTyped := v.(int64); isTyped {
return time.Unix(0, typed).Format(dateFormat)
}
if typed, isTyped := v.(float64); isTyped {
return time.Unix(0, int64(typed)).Format(dateFormat)
}
return ""
}
// IntValueFormatter is a ValueFormatter for float64.
func IntValueFormatter(v interface{}) string {
switch v.(type) {
case int:
return strconv.Itoa(v.(int))
case int64:
return strconv.FormatInt(v.(int64), 10)
case float32:
return strconv.FormatInt(int64(v.(float32)), 10)
case float64:
return strconv.FormatInt(int64(v.(float64)), 10)
default:
return ""
}
}
// FloatValueFormatter is a ValueFormatter for float64.
func FloatValueFormatter(v interface{}) string {
return FloatValueFormatterWithFormat(v, DefaultFloatFormat)
}
// PercentValueFormatter is a formatter for percent values.
// NOTE: it normalizes the values, i.e. multiplies by 100.0.
func PercentValueFormatter(v interface{}) string {
if typed, isTyped := v.(float64); isTyped {
return FloatValueFormatterWithFormat(typed*100.0, DefaultPercentValueFormat)
}
return ""
}
// FloatValueFormatterWithFormat is a ValueFormatter for float64 with a given format.
func FloatValueFormatterWithFormat(v interface{}, floatFormat string) string {
if typed, isTyped := v.(int); isTyped {
return fmt.Sprintf(floatFormat, float64(typed))
}
if typed, isTyped := v.(int64); isTyped {
return fmt.Sprintf(floatFormat, float64(typed))
}
if typed, isTyped := v.(float32); isTyped {
return fmt.Sprintf(floatFormat, typed)
}
if typed, isTyped := v.(float64); isTyped {
return fmt.Sprintf(floatFormat, typed)
}
return ""
}
// KValueFormatter is a formatter for K values.
func KValueFormatter(k float64, vf ValueFormatter) ValueFormatter {
return func(v interface{}) string {
return fmt.Sprintf("%0.0fσ %s", k, vf(v))
}
}
// FloatValueFormatter is a ValueFormatter for float64, exponential notation, e.g. 1.52e+08.
func ExponentialValueFormatter(v interface{}) string {
return FloatValueFormatterWithFormat(v, "%.2e")
}