Fix crash of the WindowToImageFilter when specifying a Viewport.

Add a test for this feature.

Rendering/Core/Testing/Cxx/CMakeLists.txt

@@ -74,6 +74,7 @@ vtk_add_test_cxx(${vtk-module}CxxTests tests
   TestTStripsNormalsColorsTCoords.cxx
   TestTStripsNormalsTCoords.cxx
   TestTStripsTCoords.cxx
+  TestWindowToImageFilter.cxx
   otherLookupTable.cxx,NO_VALID
   otherLookupTableWithEnabling.cxx,NO_VALID
   RenderNonFinite.cxx

Rendering/Core/Testing/Cxx/TestWindowToImageFilter.cxx

+/*=========================================================================
+
+  Program:   Visualization Toolkit
+  Module:    TestWindowToImageFilter.cxx
+
+  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
+  All rights reserved.
+  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
+
+  This software is distributed WITHOUT ANY WARRANTY; without even
+  the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+  PURPOSE.  See the above copyright notice for more information.
+
+=========================================================================*/
+
+#include "vtkTestUtilities.h"
+#include "vtkRegressionTestImage.h"
+
+#include "vtkActor.h"
+#include "vtkImageActor.h"
+#include "vtkImageMapper3D.h"
+#include "vtkNew.h"
+#include "vtkPolyDataMapper.h"
+#include "vtkRenderer.h"
+#include "vtkRenderWindow.h"
+#include "vtkRenderWindowInteractor.h"
+#include "vtkSphereSource.h"
+#include "vtkWindowToImageFilter.h"
+
+int TestWindowToImageFilter(int argc, char* argv[])
+{
+  vtkNew<vtkSphereSource> sphereSource;
+  sphereSource->SetCenter(0.0, 0.0, 0.0);
+  sphereSource->SetRadius(5.0);
+  sphereSource->Update();
+
+  // Render the sphere
+  vtkNew<vtkPolyDataMapper> mapper;
+  mapper->SetInputConnection(sphereSource->GetOutputPort());
+
+  vtkNew<vtkActor> actor;
+  actor->SetMapper(mapper.Get());
+
+  vtkNew<vtkRenderer> renderer;
+  vtkNew<vtkRenderWindow> renderWindow;
+  renderWindow->AddRenderer(renderer.Get());
+  renderWindow->SetMultiSamples(0);
+
+  vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
+  renderWindowInteractor->SetRenderWindow(renderWindow.Get());
+
+  renderer->AddActor(actor.Get());
+
+  renderWindow->Render();
+
+  // Take the partial screenshot
+  vtkNew<vtkWindowToImageFilter> windowToImageFilter;
+  windowToImageFilter->SetInput(renderWindow.Get());
+  windowToImageFilter->SetInputBufferTypeToRGB();
+  windowToImageFilter->SetViewport(0.5, 0.5, 0.8, 1.0);
+  windowToImageFilter->ReadFrontBufferOff(); // read from the back buffer
+  windowToImageFilter->Update();
+
+  // Show the screenshot
+  vtkNew<vtkImageActor> imageActor;
+  imageActor->GetMapper()->SetInputData(windowToImageFilter->GetOutput());
+
+  renderer->RemoveActor(actor.Get());
+  renderer->AddActor(imageActor.Get());
+
+  renderWindow->Render();
+  renderer->ResetCamera();
+  renderWindow->Render();
+
+  int retVal = vtkRegressionTestImage(renderWindow.Get());
+  if (retVal == vtkRegressionTester::DO_INTERACTOR)
+    {
+    renderWindowInteractor->Start();
+    }
+
+  return !retVal;
+}

Rendering/Core/Testing/Data/Baseline/TestWindowToImageFilter.png.md5

+2964763215a6a2c89ed8a7335b60402b

Rendering/Core/vtkWindowToImageFilter.h

@@ -108,7 +108,8 @@ public:
   // Description:
   // Set/get the extents to be used to generate the image. Initial value is
   // {0,0,1,1} (This option does not work if Magnification > 1.)
-  vtkSetVector4Macro(Viewport,double);
+  void SetViewport(double, double, double, double);
+  void SetViewport(double*);
   vtkGetVectorMacro(Viewport,double,4);
 
   // Description: