Add support for gradient background in ctkVTKRenderView

Don't support gradient background in ctkVTKSliceView as it would require
some architecture redesign (vtkLightboxRenderingManager)

Libs/Visualization/VTK/Widgets/Testing/Cpp/ctkVTKRenderViewTest1.cpp

@@ -55,6 +55,8 @@ int ctkVTKRenderViewTest1(int argc, char * argv [] )
   // Instanciate widget
   ctkVTKRenderView renderView;
   renderView.setBackgroundColor(QColor(Qt::red));
+  renderView.setBackgroundColor2(QColor(Qt::yellow));
+  renderView.setGradientBackground(true);
   renderView.setCornerAnnotationText("CTK Rocks !");
   renderView.show();
 

Libs/Visualization/VTK/Widgets/ctkVTKAbstractView.cpp

@@ -261,3 +261,71 @@ int ctkVTKAbstractView::heightForWidth(int width)const
   // typically VTK render window tend to be square...
   return width;
 }
+
+//----------------------------------------------------------------------------
+void ctkVTKAbstractView::setBackgroundColor(const QColor& newBackgroundColor)
+{
+  Q_D(ctkVTKAbstractView);
+  double color[3];
+  color[0] = newBackgroundColor.redF();
+  color[1] = newBackgroundColor.greenF();
+  color[2] = newBackgroundColor.blueF();
+  foreach(vtkRenderer* renderer, d->renderers())
+    {
+    renderer->SetBackground(color);
+    }
+}
+
+//----------------------------------------------------------------------------
+QColor ctkVTKAbstractView::backgroundColor()const
+{
+  Q_D(const ctkVTKAbstractView);
+  vtkRenderer* firstRenderer = d->firstRenderer();
+  return firstRenderer ? QColor::fromRgbF(firstRenderer->GetBackground()[0],
+                                          firstRenderer->GetBackground()[1],
+                                          firstRenderer->GetBackground()[2])
+                       : QColor();
+}
+
+//----------------------------------------------------------------------------
+void ctkVTKAbstractView::setBackgroundColor2(const QColor& newBackgroundColor)
+{
+  Q_D(ctkVTKAbstractView);
+  double color[3];
+  color[0] = newBackgroundColor.redF();
+  color[1] = newBackgroundColor.greenF();
+  color[2] = newBackgroundColor.blueF();
+  foreach(vtkRenderer* renderer, d->renderers())
+    {
+    renderer->SetBackground2(color);
+    }
+}
+
+//----------------------------------------------------------------------------
+QColor ctkVTKAbstractView::backgroundColor2()const
+{
+  Q_D(const ctkVTKAbstractView);
+  vtkRenderer* firstRenderer = d->firstRenderer();
+  return firstRenderer ? QColor::fromRgbF(firstRenderer->GetBackground2()[0],
+                                          firstRenderer->GetBackground2()[1],
+                                          firstRenderer->GetBackground2()[2])
+                       : QColor();
+}
+
+//----------------------------------------------------------------------------
+void ctkVTKAbstractView::setGradientBackground(bool enable)
+{
+  Q_D(ctkVTKAbstractView);
+  foreach(vtkRenderer* renderer, d->renderers())
+    {
+    renderer->SetGradientBackground(enable);
+    }
+}
+
+//----------------------------------------------------------------------------
+bool ctkVTKAbstractView::gradientBackground()const
+{
+  Q_D(const ctkVTKAbstractView);
+  vtkRenderer* firstRenderer = d->firstRenderer();
+  return firstRenderer ? firstRenderer->GetGradientBackground() : false;
+}

Libs/Visualization/VTK/Widgets/ctkVTKAbstractView.h

@@ -41,6 +41,8 @@ class CTK_VISUALIZATION_VTK_WIDGETS_EXPORT ctkVTKAbstractView : public QWidget
   Q_OBJECT
   Q_PROPERTY(QString cornerAnnotationText READ cornerAnnotationText WRITE setCornerAnnotationText)
   Q_PROPERTY(QColor backgroundColor READ backgroundColor WRITE setBackgroundColor)
+  Q_PROPERTY(QColor backgroundColor2 READ backgroundColor2 WRITE setBackgroundColor)
+  Q_PROPERTY(bool gradientBackground READ gradientBackground WRITE setGradientBackground)
   Q_PROPERTY(bool renderEnabled READ renderEnabled WRITE setRenderEnabled)
 public:
 
@@ -56,8 +58,16 @@ public slots:
   /// Force a render even if a render is already ocurring
   void forceRender();
 
-  /// Set background color
-  virtual void setBackgroundColor(const QColor& newBackgroundColor) = 0;
+  /// Set the background color of the rendering screen.
+  virtual void setBackgroundColor(const QColor& newBackgroundColor);
+
+  /// Set the second background color of the rendering screen for gradient
+  /// backgrounds.
+  virtual void setBackgroundColor2(const QColor& newBackgroundColor);
+
+  /// Set/Get whether this view should have a gradient background using the
+  /// Background (top) and Background2 (bottom) colors. Default is off.
+  virtual void setGradientBackground(bool enable);
 
   /// Enable/Disable rendering
   void setRenderEnabled(bool value);
@@ -84,7 +94,13 @@ public:
   Q_INVOKABLE QVTKWidget * VTKWidget() const;
 
   /// Get background color
-  virtual QColor backgroundColor() const = 0;
+  virtual QColor backgroundColor() const;
+
+  /// Get the second background color
+  virtual QColor backgroundColor2() const;
+
+  /// Is the background a gradient
+  virtual bool gradientBackground() const;
 
   /// Return if rendering is enabled
   bool renderEnabled() const;

Libs/Visualization/VTK/Widgets/ctkVTKRenderView.cpp

@@ -222,27 +222,6 @@ void ctkVTKRenderView::setInteractor(vtkRenderWindowInteractor* newInteractor)
   d->Orientation->SetInteractor(newInteractor);
 }
 
-// --------------------------------------------------------------------------
-void ctkVTKRenderView::setBackgroundColor(const QColor& newBackgroundColor)
-{
-  Q_D(ctkVTKRenderView);
-
-  logger.trace(QString("setBackgroundColor: %1").arg(newBackgroundColor.name()));
-
-  d->Renderer->SetBackground(newBackgroundColor.redF(),
-                             newBackgroundColor.greenF(),
-                             newBackgroundColor.blueF());
-}
-
-//----------------------------------------------------------------------------
-QColor ctkVTKRenderView::backgroundColor() const
-{
-  Q_D(const ctkVTKRenderView);
-  double color[3] = {0, 0, 0};
-  d->Renderer->GetBackground(color);
-  return QColor::fromRgbF(color[0], color[1], color[2]);
-}
-
 //----------------------------------------------------------------------------
 void ctkVTKRenderView::setOrientationWidgetVisible(bool visible)
 {

Libs/Visualization/VTK/Widgets/ctkVTKRenderView.h

@@ -124,12 +124,6 @@ public slots:
 
 public:
 
-  /// Set background color
-  virtual void setBackgroundColor(const QColor& newBackgroundColor);
-
-  /// Get background color
-  virtual QColor backgroundColor() const;
-
   /// Get Orientation widget visibility
   bool orientationWidgetVisible();
 

Libs/Visualization/VTK/Widgets/ctkVTKSliceView.h

@@ -30,6 +30,8 @@ class vtkCamera;
 class vtkImageData;
 class vtkRenderer;
 
+/// Specific implementation for a 2D view that supports lightbox display.
+/// \note There is no support for gradient background yet.
 class CTK_VISUALIZATION_VTK_WIDGETS_EXPORT ctkVTKSliceView : public ctkVTKAbstractView
 {
   Q_OBJECT