vtkInteractorStyleRubberBandZoom.cxx

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

  Program:   Visualization Toolkit
  Module:    vtkInteractorStyleRubberBandZoom.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 "vtkInteractorStyleRubberBandZoom.h"

#include "vtkCamera.h"
#include "vtkObjectFactory.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkRenderer.h"
#include "vtkUnsignedCharArray.h"
#include "vtkVectorOperators.h"

namespace impl
{
template <class T>
vtkVector3d GetCenter(const vtkRect<T>& rect)
{
  return vtkVector3d(
    rect.GetX() + 0.5 * rect.GetWidth(), rect.GetY() + 0.5 * rect.GetHeight(), 0.0);
}

vtkVector3d DisplayToWorld(const vtkVector3d& display, vtkRenderer* ren)
{
  ren->SetDisplayPoint(display[0], display[1], display[2]);
  ren->DisplayToView();
  ren->ViewToWorld();

  vtkVector<double, 4> world4;
  ren->GetWorldPoint(world4.GetData());
  double invw = 1.0 * world4[3];
  world4 = world4 * invw;
  return vtkVector3d(world4.GetData());
}
}

vtkStandardNewMacro(vtkInteractorStyleRubberBandZoom);

vtkInteractorStyleRubberBandZoom::vtkInteractorStyleRubberBandZoom()
{
  this->StartPosition[0] = this->StartPosition[1] = 0;
  this->EndPosition[0] = this->EndPosition[1] = 0;
  this->Moving = 0;
  this->LockAspectToViewport = false;
  this->CenterAtStartPosition = false;
  this->UseDollyForPerspectiveProjection = true;
  this->PixelArray = vtkUnsignedCharArray::New();
}

vtkInteractorStyleRubberBandZoom::~vtkInteractorStyleRubberBandZoom()
{
  this->PixelArray->Delete();
}

void vtkInteractorStyleRubberBandZoom::AdjustBox(int startPosition[2], int endPosition[2]) const
{
  if (this->LockAspectToViewport && this->CurrentRenderer != nullptr)
  {
    double aspect = this->CurrentRenderer->GetAspect()[0];

    int dx = endPosition[0] - startPosition[0];
    int dy = endPosition[1] - startPosition[1];

    // now we could adjust dx or dy. We pick one that ensures that the current end
    // position is always included in the new box. That way, the mouse is not
    // floating outside of the box.
    const int newDY = static_cast<int>(0.5 + std::abs(dx) / aspect);
    if (std::abs(dy) > newDY)
    {
      const int newDX = static_cast<int>(0.5 + aspect * std::abs(dy));
      dx = (dx < 0) ? -newDX : newDX;
    }
    else
    {
      dy = (dy < 0) ? -newDY : newDY;
    }
    endPosition[0] = startPosition[0] + dx;
    endPosition[1] = startPosition[1] + dy;
  }

  if (this->CenterAtStartPosition)
  {
    vtkVector2i dia;
    dia = vtkVector2i(endPosition) - vtkVector2i(startPosition);
    vtkVector2i newStartPosition = vtkVector2i(startPosition) - dia;
    startPosition[0] = newStartPosition.GetX();
    startPosition[1] = newStartPosition.GetY();
  }
}

void vtkInteractorStyleRubberBandZoom::OnMouseMove()
{
  if (!this->Interactor || !this->Moving)
  {
    return;
  }

  this->EndPosition[0] = this->Interactor->GetEventPosition()[0];
  this->EndPosition[1] = this->Interactor->GetEventPosition()[1];
  int *size = this->Interactor->GetRenderWindow()->GetSize();
  if (this->EndPosition[0] > (size[0]-1))
  {
    this->EndPosition[0] = size[0]-1;
  }
  if (this->EndPosition[0] < 0)
  {
    this->EndPosition[0] = 0;
  }
  if (this->EndPosition[1] > (size[1]-1))
  {
    this->EndPosition[1] = size[1]-1;
  }
  if (this->EndPosition[1] < 0)
  {
    this->EndPosition[1] = 0;
  }

  int startPosition[2] = { this->StartPosition[0], this->StartPosition[1] };
  int endPosition[2] = { this->EndPosition[0], this->EndPosition[1] };
  // Adjust box to fit aspect ratio, if needed.
  this->AdjustBox(startPosition, endPosition);

  vtkUnsignedCharArray *tmpPixelArray = vtkUnsignedCharArray::New();
  tmpPixelArray->DeepCopy(this->PixelArray);

  unsigned char *pixels = tmpPixelArray->GetPointer(0);

  int min[2], max[2];
  min[0] = startPosition[0] <= endPosition[0] ? startPosition[0] : endPosition[0];
  min[1] = startPosition[1] <= endPosition[1] ? startPosition[1] : endPosition[1];
  max[0] = endPosition[0] > startPosition[0] ? endPosition[0] : startPosition[0];
  max[1] = endPosition[1] > startPosition[1] ? endPosition[1] : startPosition[1];

  int i;
  for (i = min[0]; i <= max[0]; i++)
  {
    pixels[3*(min[1]*size[0]+i)] = 255 ^ pixels[3*(min[1]*size[0]+i)];
    pixels[3*(min[1]*size[0]+i)+1] = 255 ^ pixels[3*(min[1]*size[0]+i)+1];
    pixels[3*(min[1]*size[0]+i)+2] = 255 ^ pixels[3*(min[1]*size[0]+i)+2];
    pixels[3*(max[1]*size[0]+i)] = 255 ^ pixels[3*(max[1]*size[0]+i)];
    pixels[3*(max[1]*size[0]+i)+1] = 255 ^ pixels[3*(max[1]*size[0]+i)+1];
    pixels[3*(max[1]*size[0]+i)+2] = 255 ^ pixels[3*(max[1]*size[0]+i)+2];
  }
  for (i = min[1]+1; i < max[1]; i++)
  {
    pixels[3*(i*size[0]+min[0])] = 255 ^ pixels[3*(i*size[0]+min[0])];
    pixels[3*(i*size[0]+min[0])+1] = 255 ^ pixels[3*(i*size[0]+min[0])+1];
    pixels[3*(i*size[0]+min[0])+2] = 255 ^ pixels[3*(i*size[0]+min[0])+2];
    pixels[3*(i*size[0]+max[0])] = 255 ^ pixels[3*(i*size[0]+max[0])];
    pixels[3*(i*size[0]+max[0])+1] = 255 ^ pixels[3*(i*size[0]+max[0])+1];
    pixels[3*(i*size[0]+max[0])+2] = 255 ^ pixels[3*(i*size[0]+max[0])+2];
  }

  this->Interactor->GetRenderWindow()->SetPixelData(0, 0, size[0]-1, size[1]-1, pixels, 1);
  this->Interactor->GetRenderWindow()->Frame();

  tmpPixelArray->Delete();
}

void vtkInteractorStyleRubberBandZoom::OnLeftButtonDown()
{
  if (!this->Interactor)
  {
    return;
  }
  this->Moving = 1;

  vtkRenderWindow *renWin = this->Interactor->GetRenderWindow();

  this->StartPosition[0] = this->Interactor->GetEventPosition()[0];
  this->StartPosition[1] = this->Interactor->GetEventPosition()[1];
  this->EndPosition[0] = this->StartPosition[0];
  this->EndPosition[1] = this->StartPosition[1];

  this->PixelArray->Initialize();
  this->PixelArray->SetNumberOfComponents(3);
  int *size = renWin->GetSize();
  this->PixelArray->SetNumberOfTuples(size[0]*size[1]);

  renWin->GetPixelData(0, 0, size[0]-1, size[1]-1, 1, this->PixelArray);

  this->FindPokedRenderer(this->StartPosition[0], this->StartPosition[1]);
  if (this->CurrentRenderer)
  {
    // Ensure the aspect ratio is up-to-date.
    this->CurrentRenderer->ComputeAspect();
  }
}

void vtkInteractorStyleRubberBandZoom::OnLeftButtonUp()
{
  if (!this->Interactor || !this->Moving)
  {
    return;
  }

  if (   (this->StartPosition[0] != this->EndPosition[0])
      || (this->StartPosition[1] != this->EndPosition[1]) )
  {
    this->Zoom();
  }
  this->Moving = 0;
}

void vtkInteractorStyleRubberBandZoom::Zoom()
{
  int startPosition[2] = { this->StartPosition[0], this->StartPosition[1] };
  int endPosition[2] = { this->EndPosition[0], this->EndPosition[1] };

  // Adjust box to fit aspect ratio, if needed.
  this->AdjustBox(startPosition, endPosition);

  const vtkRecti box(startPosition[0] < endPosition[0] ? startPosition[0] : endPosition[0],
    startPosition[1] < endPosition[1] ? startPosition[1] : endPosition[1],
    std::abs(endPosition[0] - startPosition[0]), std::abs(endPosition[1] - startPosition[1]));

  vtkCamera *cam = this->CurrentRenderer->GetActiveCamera();
  if (cam->GetParallelProjection() || this->UseDollyForPerspectiveProjection)
  {
    this->ZoomTraditional(box);
  }
  else
  {
    this->ZoomPerspectiveProjectionUsingViewAngle(box);
  }
  this->Interactor->Render();
}

void vtkInteractorStyleRubberBandZoom::ZoomTraditional(const vtkRecti& box)
{
  const int* size = this->CurrentRenderer->GetSize();
  const int* origin = this->CurrentRenderer->GetOrigin();
  vtkCamera* cam = this->CurrentRenderer->GetActiveCamera();

  const vtkVector3d rbcenter = impl::GetCenter(box);
  const vtkVector3d worldRBCenter = impl::DisplayToWorld(rbcenter, this->CurrentRenderer);

  const vtkVector3d winCenter = impl::GetCenter(vtkRecti(origin[0], origin[1], size[0], size[1]));
  const vtkVector3d worldWinCenter = impl::DisplayToWorld(winCenter, this->CurrentRenderer);
  const vtkVector3d translation = worldRBCenter - worldWinCenter;

  vtkVector3d pos, fp;
  cam->GetPosition(pos.GetData());
  cam->GetFocalPoint(fp.GetData());

  pos = pos + translation;
  fp = fp + translation;

  cam->SetPosition(pos.GetData());
  cam->SetFocalPoint(fp.GetData());

  double zoomFactor;
  if (box.GetWidth() > box.GetHeight())
  {
    zoomFactor = size[0] / static_cast<double>(box.GetWidth());
  }
  else
  {
    zoomFactor = size[1] / static_cast<double>(box.GetHeight());
  }

  if (cam->GetParallelProjection())
  {
    cam->Zoom(zoomFactor);
  }
  else
  {
    // In perspective mode, zoom in by moving the camera closer.  Because we are
    // moving the camera closer, we have to be careful to try to adjust the
    // clipping planes to best match the actual position they were in before.
    double initialDistance = cam->GetDistance();
    cam->Dolly(zoomFactor);

    double finalDistance = cam->GetDistance();
    double deltaDistance = initialDistance - finalDistance;
    double clippingRange[2];
    cam->GetClippingRange(clippingRange);
    clippingRange[0] -= deltaDistance;
    clippingRange[1] -= deltaDistance;
    // Correct bringing clipping planes too close or behind camera.
    if (clippingRange[1] <= 0.0)
    {
      clippingRange[1] = 0.001;
    }
    // This near plane check comes from vtkRenderer::ResetCameraClippingRange()
    if (clippingRange[0] < 0.001*clippingRange[1])
    {
      clippingRange[0] = 0.001*clippingRange[1];
    }
    cam->SetClippingRange(clippingRange);
  }
}

void vtkInteractorStyleRubberBandZoom::ZoomPerspectiveProjectionUsingViewAngle(const vtkRecti& box)
{
  const int* size = this->CurrentRenderer->GetSize();
  vtkCamera* cam = this->CurrentRenderer->GetActiveCamera();

  const vtkVector3d rbcenter = impl::GetCenter(box);
  const vtkVector3d worldRBCenter = impl::DisplayToWorld(rbcenter, this->CurrentRenderer);
  cam->SetFocalPoint(worldRBCenter.GetData());

  double zoomFactor;
  if (box.GetWidth() > box.GetHeight())
  {
    zoomFactor = size[0] / static_cast<double>(box.GetWidth());
  }
  else
  {
    zoomFactor = size[1] / static_cast<double>(box.GetHeight());
  }

  cam->Zoom(zoomFactor);
}

void vtkInteractorStyleRubberBandZoom::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os, indent);
  os << indent << "LockAspectToViewport: " << this->LockAspectToViewport << endl;
  os << indent << "CenterAtStartPosition: " << this->CenterAtStartPosition << endl;
  os << indent << "UseDollyForPerspectiveProjection: " << this->UseDollyForPerspectiveProjection
     << endl;
}