add doc for ColorMap

Author: jube

docs/ColorMap.adoc

@@ -0,0 +1,64 @@
+= `gf::ColorMap` type
+v0.1
+include::bits/attributes.adoc[]
+:toc: right
+
+A color map can compute a color by interpolating of predefined colors.
+
+xref:core_color.adoc[< Back to `core` Color]
+
+== Description
+
+[source]
+----
+#include <gf2/core/ColorMap.h>
+class ColorMap;
+----
+
+== Member Functions
+
+=== `add_color_stop`
+
+[source]
+----
+void add_color_stop(float offset, const Color& color);
+----
+
+Add a reference color with a predefined offset.
+
+See also: <<compute_color>>
+
+=== `clear`
+
+[source]
+----
+void clear();
+----
+
+Clear the color map.
+
+See also: <<empty>>
+
+
+=== `compute_color`
+
+[source]
+----
+Color compute_color(float offset) const;
+----
+
+Compute a color associated to the given offset.
+
+See also: <<add_color_stop>>
+
+
+=== `empty`
+
+[source]
+----
+bool empty() const;
+----
+
+Tell if the color map is empty.
+
+See also: <<clear>>

docs/core_color.adoc

@@ -198,6 +198,17 @@ struct Color;
 
 A color in the link:https://en.wikipedia.org/wiki/RGB_color_model[RGB color model]. xref:Color.adoc[*Read more...*].
 
+[#color_map]
+=== `gf::ColorMap`
+
+[source]
+----
+#include <gf2/core/ColorMap.h>
+class ColorMap;
+----
+
+A color map can compute a color by interpolating of predefined colors. xref:ColorMap.adoc[*Read more...*].
+
 [#image]
 === `gf::Image`
 

include/gf2/core/ColorRamp.h

@@ -12,6 +12,11 @@ namespace gf {
 
   class GF_CORE_API ColorRamp {
   public:
+    void clear()
+    {
+      m_mapping.clear();
+    }
+
     bool empty() const
     {
       return m_mapping.empty();