Implement Axis targets.

internal/mappingrules/math.go

@@ -0,0 +1,15 @@
+package mappingrules
+
+import (
+	"golang.org/x/exp/constraints"
+)
+
+func AbsInt[T constraints.Integer](value T) T {
+	return max(value, -value)
+}
+
+// LerpInt linearly interpolates between two integer values using
+// a float64 index value
+func LerpInt[T constraints.Integer](min, max T, t float64) T {
+	return T((1-t)*float64(min) + t*float64(max))
+}