VTK-5.0.0/Rendering/vtkWindowToImageFilter.h

/*=========================================================================

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkWindowToImageFilter.h,v $

  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.

=========================================================================*/
// .NAME vtkWindowToImageFilter - Use a vtkWindow as input to image pipeline
// .SECTION Description
// vtkWindowToImageFilter provides methods needed to read the data in
// a vtkWindow and use it as input to the imaging pipeline. This is
// useful for saving an image to a file for example. The window can
// be read as either RGB or RGBA pixels;  in addition, the depth buffer
// can also be read.   RGB and RGBA pixels are of type unsigned char,
// while Z-Buffer data is returned as floats.  Use this filter
// to convert RenderWindows or ImageWindows to an image format.  
//
// .SECTION Caveats
// A vtkWindow doesn't behave like other parts of the VTK pipeline: its
// modification time doesn't get updated when an image is rendered.  As a
// result, naive use of vtkWindowToImageFilter will produce an image of
// the first image that the window rendered, but which is never updated
// on subsequent window updates.  This behavior is unexpected and in 
// general undesirable. 
//
// To force an update of the output image, call vtkWindowToImageFilter's 
// Modified method after rendering to the window.
//
// In VTK versions 4 and later, this filter is part of the canonical
// way to output an image of a window to a file (replacing the
// obsolete SaveImageAsPPM method for vtkRenderWindows that existed in
// 3.2 and earlier).  Connect this filter to the output of the window,
// and filter's output to a writer such as vtkPNGWriter.
//
// Reading back alpha planes is dependent on the correct operation of
// the render window's GetRGBACharPixelData method, which in turn is
// dependent on the configuration of the window's alpha planes.  As of
// VTK 4.4+, machine-independent behavior is not automatically 
// assured because of these dependencies.

// .SECTION see also
// vtkWindow

#ifndef __vtkWindowToImageFilter_h
#define __vtkWindowToImageFilter_h

#include "vtkAlgorithm.h"
#include "vtkImageData.h" // makes things a bit easier

// VTK_RGB and VTK_RGBA are defined in system includes
#define VTK_ZBUFFER 5

class vtkWindow;

class VTK_RENDERING_EXPORT vtkWindowToImageFilter : public vtkAlgorithm
{
public:
  static vtkWindowToImageFilter *New();

  vtkTypeRevisionMacro(vtkWindowToImageFilter,vtkAlgorithm);
  void PrintSelf(ostream& os, vtkIndent indent);   

  // Description:
  // Indicates what renderer to get the pixel data from.
  void SetInput(vtkWindow *input);

  // Description:
  // Returns which renderer is being used as the source for the pixel data.
  vtkGetObjectMacro(Input,vtkWindow);

  // Description:
  // The magnification of the current render window
  vtkSetClampMacro(Magnification,int,1,2048);
  vtkGetMacro(Magnification,int);

  // Description:
  // Set/Get the flag that determines which buffer to read from.
  // The default is to read from the front buffer.   
  vtkBooleanMacro(ReadFrontBuffer, int);
  vtkGetMacro(ReadFrontBuffer, int);
  vtkSetMacro(ReadFrontBuffer, int);
  
  // Description:
  // Set/get whether to re-render the input window. (This option makes no
  // difference if Magnification > 1.)
  vtkBooleanMacro(ShouldRerender, int);
  vtkSetMacro(ShouldRerender, int);
  vtkGetMacro(ShouldRerender, int);
  
  //Description:
  //Set/get the extents to be used to generate the image. (This option
  //does not work if Magnification > 1.)
  vtkSetVector4Macro(Viewport,double);
  vtkGetVectorMacro(Viewport,double,4);

  //Description:
  //Set/get the window buffer from which data will be read.  Choices
  //include VTK_RGB (read the color image from the window), VTK_RGBA 
  //(same, but include the alpha channel), and VTK_ZBUFFER (depth
  //buffer, returned as a float array).
  vtkSetMacro(InputBufferType, int);
  vtkGetMacro(InputBufferType, int);
  void SetInputBufferTypeToRGB() {this->SetInputBufferType(VTK_RGB);};
  void SetInputBufferTypeToRGBA() {this->SetInputBufferType(VTK_RGBA);};
  void SetInputBufferTypeToZBuffer() {this->SetInputBufferType(VTK_ZBUFFER);};


  // Description:
  // Get the output data object for a port on this algorithm.
  vtkImageData* GetOutput();

  // Description:
  // see vtkAlgorithm for details
  virtual int ProcessRequest(vtkInformation*,
                             vtkInformationVector**,
                             vtkInformationVector*);

protected:
  vtkWindowToImageFilter();
  ~vtkWindowToImageFilter();

  // vtkWindow is not a vtkDataObject, so we need our own ivar.
  vtkWindow *Input;
  int Magnification;
  int ReadFrontBuffer;
  int ShouldRerender;
  double Viewport[4];
  int InputBufferType;

  void RequestData(vtkInformation *, 
                   vtkInformationVector **, vtkInformationVector *);

  virtual void RequestInformation (vtkInformation*,
                                  vtkInformationVector**,
                                  vtkInformationVector*);

  // see algorithm for more info
  virtual int FillOutputPortInformation(int port, vtkInformation* info);

private:
  vtkWindowToImageFilter(const vtkWindowToImageFilter&);  // Not implemented.
  void operator=(const vtkWindowToImageFilter&);  // Not implemented.
};

#endif