Add Luminance::value_in_foot_lamberts().

2 files changed, 16 insertions, 0 deletions

diff --git a/src/types.cc b/src/types.cc
index 44422ca9..743e7260 100644
--- a/src/types.cc
+++ b/src/types.cc
@@ -547,6 +547,20 @@ Luminance::string_to_unit (string u)
 }
 
 
+float
+Luminance::value_in_foot_lamberts () const
+{
+	switch (_unit) {
+	case Unit::CANDELA_PER_SQUARE_METRE:
+		return _value / 3.426;
+	case Unit::FOOT_LAMBERT:
+		return _value;
+	default:
+		DCP_ASSERT (false);
+	}
+}
+
+
 bool
 dcp::operator== (Luminance const& a, Luminance const& b)
 {
diff --git a/src/types.h b/src/types.h
index 374dd8b8..9dc3e5f5 100644
--- a/src/types.h
+++ b/src/types.h
@@ -444,6 +444,8 @@ public:
 		return _unit;
 	}
 
+	float value_in_foot_lamberts () const;
+
 	void as_xml (xmlpp::Element* parent, std::string ns) const;
 
 	static std::string unit_to_string (Unit u);