1 files changed, 30 insertions, 0 deletions
diff --git a/dw/imgrenderer.hh b/dw/imgrenderer.hh
index 9c7c6525..1efeef8c 100644
--- a/dw/imgrenderer.hh
+++ b/dw/imgrenderer.hh
@@ -16,10 +16,40 @@ namespace core {
 class ImgRenderer
 {
 public:
+   virtual ~ImgRenderer () { }
+
    virtual void setBuffer (core::Imgbuf *buffer, bool resize = false) = 0;
    virtual void drawRow (int row) = 0;
 };
 
+/**
+ * \brief Implementation of ImgRenderer, which distributes all calls
+ * to a set of other implementations of ImgRenderer.
+ *
+ * The order of the call children is not defined, especially not
+ * identical to the order in which they have been added.
+ */
+class ImgRendererDist: public ImgRenderer
+{
+   lout::container::typed::HashSet <lout::object::TypedPointer <ImgRenderer> >
+      *children;
+
+public:
+   inline ImgRendererDist ()
+   { children = new lout::container::typed::HashSet
+         <lout::object::TypedPointer <ImgRenderer> > (true); }
+   ~ImgRendererDist () { delete children; }
+
+   void setBuffer (core::Imgbuf *buffer, bool resize);
+   void drawRow (int row);
+
+   void put (ImgRenderer *child)
+   { children->put (new lout::object::TypedPointer <ImgRenderer> (child)); }
+   void remove (ImgRenderer *child)
+   { lout::object::TypedPointer <ImgRenderer> tp (child);
+     children->remove (&tp); }
+};
+
 } // namespace core
 } // namespace dw