Adding upstream version 2.1.2.

Signed-off-by: Daniel Baumann <daniel@debian.org>

continuous_range.go

@@ -0,0 +1,81 @@
+package chart
+
+import (
+	"fmt"
+	"math"
+)
+
+// ContinuousRange represents a boundary for a set of numbers.
+type ContinuousRange struct {
+	Min        float64
+	Max        float64
+	Domain     int
+	Descending bool
+}
+
+// IsDescending returns if the range is descending.
+func (r ContinuousRange) IsDescending() bool {
+	return r.Descending
+}
+
+// IsZero returns if the ContinuousRange has been set or not.
+func (r ContinuousRange) IsZero() bool {
+	return (r.Min == 0 || math.IsNaN(r.Min)) &&
+		(r.Max == 0 || math.IsNaN(r.Max)) &&
+		r.Domain == 0
+}
+
+// GetMin gets the min value for the continuous range.
+func (r ContinuousRange) GetMin() float64 {
+	return r.Min
+}
+
+// SetMin sets the min value for the continuous range.
+func (r *ContinuousRange) SetMin(min float64) {
+	r.Min = min
+}
+
+// GetMax returns the max value for the continuous range.
+func (r ContinuousRange) GetMax() float64 {
+	return r.Max
+}
+
+// SetMax sets the max value for the continuous range.
+func (r *ContinuousRange) SetMax(max float64) {
+	r.Max = max
+}
+
+// GetDelta returns the difference between the min and max value.
+func (r ContinuousRange) GetDelta() float64 {
+	return r.Max - r.Min
+}
+
+// GetDomain returns the range domain.
+func (r ContinuousRange) GetDomain() int {
+	return r.Domain
+}
+
+// SetDomain sets the range domain.
+func (r *ContinuousRange) SetDomain(domain int) {
+	r.Domain = domain
+}
+
+// String returns a simple string for the ContinuousRange.
+func (r ContinuousRange) String() string {
+	if r.GetDelta() == 0 {
+		return "ContinuousRange [empty]"
+	}
+	return fmt.Sprintf("ContinuousRange [%.2f,%.2f] => %d", r.Min, r.Max, r.Domain)
+}
+
+// Translate maps a given value into the ContinuousRange space.
+func (r ContinuousRange) Translate(value float64) int {
+	normalized := value - r.Min
+	ratio := normalized / r.GetDelta()
+
+	if r.IsDescending() {
+		return r.Domain - int(math.Ceil(ratio*float64(r.Domain)))
+	}
+
+	return int(math.Ceil(ratio * float64(r.Domain)))
+}