enh(graphics): add default visibility configuration for SNegato2D

Uses the tag from IAdaptor to configure default visibility in `SNegato2D`.  
Enables the possibility to hide the adaptor by default in the xml configuration

Closes #634

Merge branch '634-graphics-add-default-visibility-configuration-for-snegato2d' into 'dev'

See merge request sight/sight!513

modules/visu/visuOgreAdaptor/include/visuOgreAdaptor/SNegato2D.hpp

@@ -46,13 +46,17 @@ namespace visuOgreAdaptor
  * - \b sliceType(int, int): updates image slice index .
  * - \b sliceIndex(int, int, int): updates image slice type.
  * - @deprecated \b newImage(): updates the image display to show the new content. call \b update() instead.
+ * - \b updateVisibility(bool): shows or hides the negato.
+ * - \b toggleVisibility(): toggle whether the negato is shown or not.
+ * - \b show(): shows the negato.
+ * - \b hide(): hides the negato.
  *
  * @section XML XML Configuration
  * @code{.xml}
     <service type="::visuOgreAdaptor::SNegato2D">
         <inout key="image" uid="..." />
         <inout key="tf" uid="..." optional="yes" />
-        <config layer="default" sliceIndex="axial" filtering="none" tfalpha="true" />
+        <config layer="default" sliceIndex="axial" filtering="none" tfalpha="true" visible="true" />
    </service>
    @endcode
  *
@@ -67,6 +71,7 @@ namespace visuOgreAdaptor
  * - \b filtering (optional, none/linear/anisotropic, default=none): texture filter type of the negato.
  * - \b tfalpha (optional, bool, default=false): if true, the alpha channel of the transfer function is used.
  * - \b border (optional, bool, default=true): allows to display the plane border.
+ * - \b visible (optional, bool, default=true): the visibility of the adaptor.
  */
 class VISUOGREADAPTOR_CLASS_API SNegato2D final : public ::fwRenderOgre::IAdaptor
 {
@@ -116,6 +121,12 @@ protected:
     /// Disconnects the attached data from the received slot.
     VISUOGREADAPTOR_API void stopping() override;
 
+    /**
+     * @brief Sets the negato visibility.
+     * @param _visible the visibility status of the negato.
+     */
+    VISUOGREADAPTOR_API void setVisible(bool _visible) override;
+
 private:
 
     /// Updates the displayed transfer function.

modules/visu/visuOgreAdaptor/src/visuOgreAdaptor/SNegato2D.cpp

@@ -149,6 +149,7 @@ void SNegato2D::starting()
                                                         m_orientation, m_3DOgreTexture, m_filtering, m_border);
 
     this->newImage();
+    this->setVisible(m_isVisible);
 }
 
 //------------------------------------------------------------------------------
@@ -173,6 +174,7 @@ void SNegato2D::stopping()
 void SNegato2D::updating()
 {
     this->newImage();
+    this->setVisible(m_isVisible);
     this->requestRender();
 }
 
@@ -360,10 +362,24 @@ void SNegato2D::updateTF()
 void SNegato2D::createPlane(const ::Ogre::Vector3& _spacing)
 {
     this->getRenderService()->makeCurrent();
+
     // Fits the plane to the new texture
     m_plane->setVoxelSpacing(_spacing);
     m_plane->initializePlane();
+
     m_plane->enableAlpha(m_enableAlpha);
 }
 
+//------------------------------------------------------------------------------
+void SNegato2D::setVisible(bool _visible)
+{
+    if(m_negatoSceneNode)
+    {
+        m_negatoSceneNode->setVisible(_visible);
+
+        this->requestRender();
+    }
+}
+
+//-----------------------------------------------------------------------------
 } // namespace visuOgreAdaptor.