From e45e01ee8e8fa9b4a6a35d7cf41b2e5a670dc272 Mon Sep 17 00:00:00 2001
From: Norman Feske <norman.feske@genode-labs.com>
Date: Wed, 1 Jul 2015 11:19:12 +0200
Subject: [PATCH] gems: HSV-to-RGB color-conversion function

---
 repos/gems/include/gems/color_hsv.h | 46 +++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 repos/gems/include/gems/color_hsv.h

diff --git a/repos/gems/include/gems/color_hsv.h b/repos/gems/include/gems/color_hsv.h
new file mode 100644
index 0000000000..0c3df824f4
--- /dev/null
+++ b/repos/gems/include/gems/color_hsv.h
@@ -0,0 +1,46 @@
+/*
+ * \brief   Color-conversion between HSV and RGB color spaces
+ * \date    2015-07-01
+ * \author  Norman Feske
+ */
+
+/*
+ * Copyright (C) 2015 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
+#ifndef _INCLUDE__GEMS__COLOR_HSV_H_
+#define _INCLUDE__GEMS__COLOR_HSV_H_
+
+#include <util/color.h>
+
+/**
+ * Create color from specified hue, saturation, and value
+ */
+static inline Genode::Color color_from_hsv(unsigned h, unsigned s, unsigned v)
+{
+	typedef Genode::Color Color;
+
+	if (s == 0)
+		return Color(v, v, v);
+
+	unsigned char const region = h / 43;
+	unsigned char const remainder = (h - (region*43)) * 6;
+	unsigned char const p = (v*(255 - s)) >> 8,
+	                    q = (v*(255 - ((s*remainder) >> 8))) >> 8,
+	                    t = (v*(255 - ((s*(255 - remainder)) >> 8))) >> 8;
+
+	switch (region) {
+	case 0:  return Color(v, t, p);
+	case 1:  return Color(q, v, p);
+	case 2:  return Color(p, v, t);
+	case 3:  return Color(p, q, v);
+	case 4:  return Color(t, p, v);
+	}
+
+	return Color(v, p, q);
+}
+
+#endif /* _INCLUDE__GEMS__COLOR_HSV_H_ */