Method Capture

Rendering/Parallel/vtkSynchronizedRenderers.cxx:790–846

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//------------------------------------------------------------------------------
bool vtkSynchronizedRenderers::vtkRawImage::Capture(vtkRenderer* ren)
{
  double viewport[4];
  ren->GetViewport(viewport);

  int window_size[2];
  window_size[0] = ren->GetVTKWindow()->GetActualSize()[0];
  window_size[1] = ren->GetVTKWindow()->GetActualSize()[1];

  int viewport_in_pixels[4];
  viewport_in_pixels[0] = static_cast<int>(window_size[0] * viewport[0]);
  viewport_in_pixels[1] = static_cast<int>(window_size[1] * viewport[1]);
  viewport_in_pixels[2] = static_cast<int>(window_size[0] * viewport[2]) - 1;
  viewport_in_pixels[3] = static_cast<int>(window_size[1] * viewport[3]) - 1;

  // we need to ensure that the size computation is always done in pixels,
  // otherwise we end up with rounding issues. In short, avoid doing
  // additions/subtractions using normalized viewport coordinates. Those are
  // better done in pixels.
  int image_size[2];
  image_size[0] = viewport_in_pixels[2] - viewport_in_pixels[0] + 1;
  image_size[1] = viewport_in_pixels[3] - viewport_in_pixels[1] + 1;

  // using RGBA always?
  this->Resize(image_size[0], image_size[1], 4);

  ren->GetRenderWindow()->GetRGBACharPixelData(viewport_in_pixels[0], viewport_in_pixels[1],
    viewport_in_pixels[2], viewport_in_pixels[3], 0, this->GetRawPtr(),
    /*right=*/ren->GetActiveCamera()->GetLeftEye() == 0);

  // if selecting then pass the processed pixel buffer
  vtkHardwareSelector* sel = ren->GetSelector();
  if (sel)
  {
    unsigned char* passdata = sel->GetPixelBuffer(sel->GetCurrentPass());
    unsigned char* destdata = this->GetRawPtr()->GetPointer(0);
    if (passdata && destdata)
    {
      unsigned int* area = sel->GetArea();
      unsigned int passwidth = area[2] - area[0] + 1;
      for (int y = 0; y < image_size[1]; ++y)
      {
        for (int x = 0; x < image_size[0]; ++x)
        {
          unsigned char* pdptr = passdata + (y * passwidth + x) * 3;
          destdata[0] = pdptr[0];
          destdata[1] = pdptr[1];
          destdata[2] = pdptr[2];
          destdata += 4;
        }
      }
    }
  }

  this->MarkValid();
  return true;
}