ENH: Testing interactor takes care of images.

Let the testing interactor take care of the image comparisons when
appropriate. Currently has a hard coded tolerance of 40, which should
work for most of the chart tests.

Charts/Testing/Cxx/TestContext.cxx

@@ -56,11 +56,8 @@ int TestContext( int argc, char * argv [] )
       ->SetStringRendererToFreeType();
 
   view->GetRenderWindow()->SetMultiSamples(0);
-  view->GetRenderWindow()->Render();
-
-  int retVal = vtkRegressionTestImage(view->GetRenderWindow());
   view->GetInteractor()->Start();
-  return !retVal;
+  return EXIT_SUCCESS;
 }
 
 // Make our new derived class to draw a diagram

Charts/Testing/Cxx/TestContextImage.cxx

@@ -46,9 +46,6 @@ int TestContextImage(int argc, char * argv [])
   item->SetPosition(25, 30);
 
   view->GetRenderWindow()->SetMultiSamples(0);
-  view->GetRenderWindow()->Render();
-
-  int retVal = vtkRegressionTestImage(view->GetRenderWindow());
   view->GetInteractor()->Start();
-  return !retVal;
+  return EXIT_SUCCESS;
 }

Charts/Testing/Cxx/TestDiagram.cxx

@@ -64,11 +64,8 @@ int TestDiagram( int argc, char * argv [] )
   VTK_CREATE(vtkRenderWindowInteractor, interactor);
   interactor->SetRenderWindow(renderWindow);
   renderWindow->SetMultiSamples(0);
-  renderWindow->Render();
-
-  int retVal = vtkRegressionTestImage(renderWindow);
   interactor->Start();
-  return !retVal;
+  return EXIT_SUCCESS;
 }
 
 // Make our new derived class to draw a diagram

Charts/Testing/Cxx/TestLinePlot.cxx

@@ -23,7 +23,6 @@
 #include "vtkContextView.h"
 #include "vtkContextScene.h"
 #include "vtkRenderWindowInteractor.h"
-#include "vtkRegressionTestImage.h"
 
 //----------------------------------------------------------------------------
 int TestLinePlot( int argc, char * argv [] )
@@ -78,7 +77,6 @@ int TestLinePlot( int argc, char * argv [] )
 
   //Finally render the scene and compare the image to a reference image
   view->GetRenderWindow()->SetMultiSamples(0);
-  int retVal = vtkRegressionTestImageThreshold(view->GetRenderWindow(), 25);
   view->GetInteractor()->Start();
-  return !retVal;
+  return EXIT_SUCCESS;
 }

Charts/Testing/Cxx/TestLinePlotInteraction.cxx

@@ -196,8 +196,7 @@ int TestLinePlotInteraction(int argc, char * argv[])
   // testing option fails.
   recorder->Off();
 
-  int retVal = vtkRegressionTestImageThreshold(view->GetRenderWindow(), 25);
   view->GetInteractor()->Start();
 
-  return !retVal;
+  return EXIT_SUCCESS;
 }