refactor and compressor map image widget

1 files changed, 71 insertions, 0 deletions

diff --git a/temperature/temperature.go b/temperature/temperature.go
new file mode 100644
index 0000000..2a135df
--- /dev/null
+++ b/temperature/temperature.go
@@ -0,0 +1,71 @@
+package temperature
+
+import (
+	"errors"
+	"fmt"
+)
+
+type unit int
+
+const (
+	Celcius unit = iota
+	Kelvin
+	Fahrenheit
+)
+
+// UnitStrings returns a slice of strings, each representing a
+// unit.
+// This is necessary because giu.Combo only works with strings.
+func UnitStrings() []string {
+	return []string{"°C", "°K", "°F"}
+}
+
+const (
+	DefaultUnit unit = Celcius
+	// DefaultUnitIndex is used to index UnitStrings().
+	DefaultUnitIndex int32 = 0 // celcius
+)
+
+func UnitFromString(s string) (unit, error) {
+	// Each case corresponds to a value in UnitStrings().
+	switch s {
+	case "°C":
+		return Celcius, nil
+	case "°K":
+		return Kelvin, nil
+	case "°F":
+		return Fahrenheit, nil
+	default:
+		return *new(unit), errors.New(fmt.Sprintf("invalid unit: '%s'", s))
+	}
+}
+
+type Temperature struct {
+	Val  float32
+	Unit unit
+}
+
+func (t Temperature) AsUnit(u unit) (float32, error) {
+	// Convert to celcius
+	var c float32
+	switch t.Unit {
+	case Celcius:
+		c = t.Val
+	case Kelvin:
+		c = t.Val - 272.15
+	case Fahrenheit:
+		c = (t.Val - 32.0) * (5.0 / 9.0)
+	}
+
+	// Convert to desired unit
+	switch u {
+	case Celcius:
+		return c, nil
+	case Kelvin:
+		return c + 272.15, nil
+	case Fahrenheit:
+		return c*(9.0/5.0) + 32.0, nil
+	default:
+		return 0, errors.New(fmt.Sprintf("invalid unit: '%v'", u))
+	}
+}