From 2e7698c4e660488194a4a1a094187215668e4ceb Mon Sep 17 00:00:00 2001
From: Vincent van Ravesteijn <vfr@lyx.org>
Date: Mon, 9 Feb 2009 20:00:31 +0000
Subject: [PATCH] Add a new Color class. This class makes it possible to
 specify a color as a merging of two other colors. The actual computation of
 the new color is done in ColorCache::get.

See:
http://thread.gmane.org/gmane.editors.lyx.devel/114189

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@28420 a592a061-630c-0410-9148-cb99ea01b6c8
---
 src/Color.cpp                    | 39 ++++++++++++++++++++++++++++++++
 src/Color.h                      | 35 ++++++++++++++++++++++++++++
 src/frontends/qt4/ColorCache.cpp | 18 +++++++++++----
 src/frontends/qt4/ColorCache.h   |  4 ++--
 4 files changed, 90 insertions(+), 6 deletions(-)

diff --git a/src/Color.cpp b/src/Color.cpp
index 7995eba380..6c6e32481f 100644
--- a/src/Color.cpp
+++ b/src/Color.cpp
@@ -84,6 +84,45 @@ RGBColor rgbFromHexName(string const & x11hexname)
 }
 
 
+Color::Color(ColorCode base_color) : baseColor(base_color), 
+	mergeColor(Color_ignore)
+{}
+
+
+bool Color::operator==(Color const & color) const
+{
+	return baseColor == color.baseColor;
+}
+
+
+bool Color::operator!=(Color const & color) const	
+{
+	return baseColor != color.baseColor;
+}
+
+
+bool Color::operator<(Color const & color) const
+{
+	return baseColor < color.baseColor;
+}
+
+
+bool Color::operator<=(Color const & color) const
+{
+	return baseColor <= color.baseColor;
+}
+
+
+std::ostream & operator<<(std::ostream & os, Color color)
+{
+	os << to_ascii(lcolor.getGUIName(color.baseColor));
+	if (color.mergeColor != Color_ignore)
+		os << "[merged with:"
+			<< to_ascii(lcolor.getGUIName(color.mergeColor)) << "]";
+	return os;
+}
+
+
 ColorSet::ColorSet()
 {
 	char const * grey40 = "#666666";
diff --git a/src/Color.h b/src/Color.h
index 2841dc5ba6..ec1a2d9ba4 100644
--- a/src/Color.h
+++ b/src/Color.h
@@ -28,6 +28,41 @@
 
 namespace lyx {
 
+/**
+ * \class Color
+ *
+ * A class holding a definition of a certain color.
+ *
+ * A color can be one of the following kinds:
+ *
+ * - a single color, then mergeColor = Color_ignore
+ * - a merged color, i.e. the average of the base and merge colors.
+ */
+
+class Color
+{
+public:
+	///
+	Color(ColorCode base_color = Color_none);
+	
+	/// comparison operators.
+	//@{
+	bool operator==(Color const & color) const;
+	bool operator!=(Color const & color) const;
+	bool operator<(Color const & color) const;
+	bool operator<=(Color const & color) const;
+	//@}
+
+	/// the base color
+	ColorCode baseColor;
+	/// The color that is merged with the base color. Set
+	/// mergeColor to Color_ignore if no merging is wanted.
+	ColorCode mergeColor;
+};
+
+std::ostream & operator<<(std::ostream & os, Color color);
+
+
 /**
  * \class ColorSet
  *
diff --git a/src/frontends/qt4/ColorCache.cpp b/src/frontends/qt4/ColorCache.cpp
index 69520fc738..dde6bc6368 100644
--- a/src/frontends/qt4/ColorCache.cpp
+++ b/src/frontends/qt4/ColorCache.cpp
@@ -28,14 +28,24 @@ void ColorCache::init()
 
 
 /// get the given color
-QColor ColorCache::get(ColorCode color) const
+QColor ColorCache::get(Color color) const
 {
 	if (!initialized_)
 		const_cast<ColorCache *>(this)->init();
-	if (color <= Color_ignore)
-		return lcolors_[color];
+	if (color <= Color_ignore && color.mergeColor == Color_ignore)
+		return lcolors_[color.baseColor];
+	if (color.mergeColor != Color_ignore) {
+		// FIXME: This would ideally be done in the Color class, but
+		// that means that we'd have to use the Qt code in the core.
+		QColor base_color = get(color.baseColor).toRgb();
+		QColor merge_color = get(color.mergeColor).toRgb();
+		return QColor(
+			(base_color.red() + merge_color.red())/2,
+			(base_color.green() + merge_color.green())/2,
+			(base_color.blue() + merge_color.blue())/2);
+	}
 	// used by branches
-	return QColor(lcolor.getX11Name(color).c_str()); 
+	return QColor(lcolor.getX11Name(color.baseColor).c_str()); 
 }
 
 
diff --git a/src/frontends/qt4/ColorCache.h b/src/frontends/qt4/ColorCache.h
index 1716d5c044..88db6bb565 100644
--- a/src/frontends/qt4/ColorCache.h
+++ b/src/frontends/qt4/ColorCache.h
@@ -12,7 +12,7 @@
 #ifndef COLORCACHE_H
 #define COLORCACHE_H
 
-#include "ColorCode.h"
+#include "Color.h"
 
 #include <QColor>
 
@@ -29,7 +29,7 @@ public:
 	ColorCache() : initialized_(false) {}
 
 	/// get the given color
-	QColor get(ColorCode color) const;
+	QColor get(Color color) const;
 
 	/// clear all colors
 	void clear() { initialized_ = false; }
-- 
2.39.5