Method ClipPlotData

Rendering/Annotation/vtkXYPlotActor.cxx:2473–2589

------------------------------------------------------------------------------ This assumes that there are multiple polylines

//------------------------------------------------------------------------------
// This assumes that there are multiple polylines
void vtkXYPlotActor::ClipPlotData(int* pos, int* pos2, vtkPolyData* pd)
{
  vtkPoints* points = pd->GetPoints();
  vtkPoints* newPoints;
  vtkCellArray* lines = pd->GetLines();
  vtkCellArray *newLines, *newVerts;
  vtkIdType numPts = pd->GetNumberOfPoints();
  vtkIdType npts = 0;
  vtkIdType newPts[2];
  const vtkIdType* pts = nullptr;
  vtkIdType i, id;
  int j;
  double x1[3], x2[3], px[3], n[3], xint[3], t;
  double p1[2], p2[2];

  p1[0] = (double)pos[0];
  p1[1] = (double)pos[1];
  p2[0] = (double)pos2[0];
  p2[1] = (double)pos2[1];

  newPoints = vtkPoints::New();
  newPoints->Allocate(numPts);
  newVerts = vtkCellArray::New();
  newVerts->AllocateCopy(lines);
  newLines = vtkCellArray::New();
  newLines->AllocateCopy(lines);
  int* pointMap = new int[numPts];
  for (i = 0; i < numPts; i++)
  {
    pointMap[i] = -1;
  }

  // Loop over polyverts eliminating those that are outside
  for (lines->InitTraversal(); lines->GetNextCell(npts, pts);)
  {
    // loop over verts keeping only those that are not clipped
    for (i = 0; i < npts; i++)
    {
      points->GetPoint(pts[i], x1);

      if (x1[0] >= p1[0] && x1[0] <= p2[0] && x1[1] >= p1[1] && x1[1] <= p2[1])
      {
        id = newPoints->InsertNextPoint(x1);
        pointMap[i] = id;
        newPts[0] = id;
        newVerts->InsertNextCell(1, newPts);
      }
    }
  }

  // Loop over polylines clipping each line segment
  for (lines->InitTraversal(); lines->GetNextCell(npts, pts);)
  {
    // loop over line segment making up the polyline
    for (i = 0; i < (npts - 1); i++)
    {
      points->GetPoint(pts[i], x1);
      points->GetPoint(pts[i + 1], x2);