Gui: cache color bar width to avoid to compute it for every resize of the canvas

src/Gui/SoFCColorBar.cpp

@@ -45,7 +45,7 @@ SO_NODE_ABSTRACT_SOURCE(SoFCColorBarBase)
 /*!
   Constructor.
 */
-SoFCColorBarBase::SoFCColorBarBase(): _windowSize(0,0)
+SoFCColorBarBase::SoFCColorBarBase() : _boxWidth(-1.0f), _windowSize(0,0)
 {
     SO_NODE_CONSTRUCTOR(SoFCColorBarBase);
 }
@@ -80,8 +80,17 @@ void SoFCColorBarBase::GLRenderBelowPath(SoGLRenderAction *  action)
     SoSeparator::GLRenderBelowPath(action);
 }
 
+void SoFCColorBarBase::setModified()
+{
+    _boxWidth = -1.0f;
+}
+
 float SoFCColorBarBase::getBoundingWidth(const SbVec2s& size)
 {
+    if (_boxWidth >= 0.0f) {
+        return _boxWidth;
+    }
+
     // These are the same camera settings for front nodes as defined in the 3d view
     SoOrthographicCamera* cam = new SoOrthographicCamera;
     cam->position = SbVec3f(0, 0, 5); // the 5 is just a value > 0
@@ -103,6 +112,7 @@ float SoFCColorBarBase::getBoundingWidth(const SbVec2s& size)
     group->unref();
 
     float boxWidth = maxPt[0] - minPt[0];
+    _boxWidth = boxWidth;
     return boxWidth;
 }
 

src/Gui/SoFCColorBar.h

@@ -129,11 +129,16 @@ protected:
    * This method must be implemented in subclasses.
    */
   virtual void setViewportSize( const SbVec2s& size ) = 0;
+  /**
+   * Mark the object as modified.
+   */
+  void setModified();
 
   SoFCColorBarBase ();
   virtual ~SoFCColorBarBase ();
 
 private:
+  float _boxWidth;
   SbVec2s _windowSize;
 };
 

src/Gui/SoFCColorGradient.cpp

@@ -108,6 +108,8 @@ void SoFCColorGradient::setMarkerLabel(const SoMFString& label)
             labels->addChild(text2);
         }
     }
+
+    setModified();
 }
 
 void SoFCColorGradient::setViewportSize(const SbVec2s& size)

src/Gui/SoFCColorLegend.cpp

@@ -245,6 +245,8 @@ void SoFCColorLegend::setLegendLabels(const App::ColorLegend& legend, int prec)
 
     setMarkerLabel(labels);
     setMarkerValue(values);
+
+    setModified();
 }
 
 void SoFCColorLegend::modifyPoints(const SbBox2f& box)