Cleaned up VtkToPng code.

Added option to fix scalar range.

utilities/PostProcessing/Extras/VtkToPng.cpp

-/*
- * VtkToPng.cpp
- *
- *  Created on: 20 Feb 2013
- *      Author: cc
- */
-
-//#include <vtkVersion.h>
-//#if VTK_MAJOR_VERSION == 6
-//int main(int, char *argv[])
-//{
-//  std::cout << argv[0] << " requires VTK 5.10 or earlier. This VTK version is " << vtkVersion::GetVTKVersion() << std::endl;
-//  return EXIT_SUCCESS;
-//}
-//#else
+///////////////////////////////////////////////////////////////////////////////
+//
+// File VtkToPng.cpp
+//
+// For more information, please see: http://www.nektar.info
+//
+// The MIT License
+//
+// Copyright (c) 2006 Division of Applied Mathematics, Brown University (USA),
+// Department of Aeronautics, Imperial College London (UK), and Scientific
+// Computing and Imaging Institute, University of Utah (USA).
+//
+// License for the specific language governing rights and limitations under
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+//
+// Description: Render a VTK Unstructured Grid file as a PNG
+//
+///////////////////////////////////////////////////////////////////////////////
+
 #include <vtkActor.h>
 #include <vtkRenderWindow.h>
 #include <vtkRenderer.h>
@@ -34,6 +54,15 @@ using namespace std;
 
 int main(int argc, char * argv[])
 {
+    if (argc != 2 && argc != 4)
+    {
+        cout << "Usage: VtkToPng vtk-file [lower upper]" << endl;
+        exit(-1);
+    }
+
+    string vInput = argv[1];
+    string vOutput = vInput.substr(0, vInput.find_last_of('.')) + ".png";
+
     // Setup offscreen rendering
     vtkSmartPointer<vtkGraphicsFactory> graphics_factory =
             vtkSmartPointer<vtkGraphicsFactory>::New();
@@ -44,20 +73,27 @@ int main(int argc, char * argv[])
             vtkSmartPointer<vtkImagingFactory>::New();
     imaging_factory->SetUseMesaClasses( 1 );
 
-  // Create a poly data reader
-  cout << "Reading file: " << argv[1] << endl;
+    // Create a poly data reader and retrieve dataset from file
     vtkXMLUnstructuredGridReader* reader = vtkXMLUnstructuredGridReader::New();
-  reader->SetFileName (argv[1]);
+    reader->SetFileName(vInput.c_str());
     reader->Update();
-  vtkDataSet* data = reader->GetOutputAsDataSet();
 
+    vtkDataSet* data = reader->GetOutputAsDataSet();
     data->GetPointData()->SetActiveScalars("u");
 
+    double scalar_range[2];
+    data->GetScalarRange(scalar_range);
+    if (argc == 4)
+    {
+        scalar_range[0] = atof(argv[2]);
+        scalar_range[1] = atof(argv[3]);
+    }
+
     // Lookup table
     vtkSmartPointer<vtkLookupTable> lookup = vtkSmartPointer<vtkLookupTable>::New();
     lookup->SetHueRange(0.0,1.0);
     lookup->SetSaturationRange(1,1);
-  lookup->SetTableRange(data->GetScalarRange());
+    lookup->SetTableRange(scalar_range);
     lookup->SetValueRange(1,1);
     lookup->Build();
 
@@ -68,7 +104,8 @@ int main(int argc, char * argv[])
     mapper->ImmediateModeRenderingOn();
     mapper->ScalarVisibilityOn();
     mapper->SetScalarModeToUsePointData();
-  mapper->SetScalarRange(data->GetScalarRange());
+    mapper->UseLookupTableScalarRangeOn();
+    //mapper->SetScalarRange(data->GetScalarRange());
     mapper->SetLookupTable(lookup);
 
 
@@ -76,12 +113,11 @@ int main(int argc, char * argv[])
             vtkSmartPointer<vtkActor>::New();
     actor->SetMapper(mapper);
 
-  // The usual rendering stuff.
+    // Configure camera position and direction
     vtkCamera *camera = vtkCamera::New();
     camera->SetPosition(0.0,-1.0,1.0);
     camera->SetFocalPoint(0,0,0);
 
-
     // A renderer and render window
     vtkSmartPointer<vtkRenderer> renderer =
             vtkSmartPointer<vtkRenderer>::New();
@@ -98,19 +134,19 @@ int main(int argc, char * argv[])
 
     renderWindow->Render();
 
+    // Create an image of scene
     vtkSmartPointer<vtkWindowToImageFilter> windowToImageFilter =
             vtkSmartPointer<vtkWindowToImageFilter>::New();
     windowToImageFilter->SetInput(renderWindow);
     windowToImageFilter->SetMagnification(4);
     windowToImageFilter->Update();
 
-  cout << "Writing file: " << argv[2] << endl;
+    // Write image to PNG
     vtkSmartPointer<vtkPNGWriter> writer =
             vtkSmartPointer<vtkPNGWriter>::New();
-  writer->SetFileName(argv[2]);
+    writer->SetFileName(vOutput.c_str());
     writer->SetInputConnection(windowToImageFilter->GetOutputPort());
     writer->Write();
 
     return EXIT_SUCCESS;
 }
-//#endif