[vtkusers] Drawing a simple line graph

[John Platt]

Hi,

By default, vtkPolyDataMapper2D, transforms 3D data into 2D data by
ignoring the z-coordinate of the 3D points in vtkPolyData, and taking
the (x,y) values as VIEWPORT values (pixel centers relative to the
lower-left corner of the viewport in the render window).

What values have you used in 'polyLinePoints'.

John.

-----Original Message-----
From: vtkusers-bounces+jcplatt=dsl.pipex.com at vtk.org
[mailto:vtkusers-bounces+jcplatt=dsl.pipex.com at vtk.org] On Behalf Of
beth at portugalmail.pt
Sent: 17 November 2006 13:33
To: John Platt
Cc: vtkusers at vtk.org
Subject: RE: [vtkusers] Drawing a simple line graph 

Hi,

Yes, I know that Position2 is relative to Position. But evend adjusting
other 
values, it does not work.
No, I can try to use vtkXYPlotActor, however I do want also to create an
area 
graph (using a polygon instead a polyline), and for that, I'll have to
know 
how to work properly with this situation...

Any other tip?

Thanks and best regards,

Elizabeth


Citando John Platt <jcplatt at dsl.pipex.com>:

 Hi,
 
 I seem to recall that the Position2 coordinate is relative to Position.
 
 Is there any reason you cannot use vtkXYPlotActor?
 
 John.
 
 -----Original Message-----
 From: vtkusers-bounces+jcplatt=dsl.pipex.com at vtk.org
 [mailto:vtkusers-bounces+jcplatt=dsl.pipex.com at vtk.org] On Behalf Of
 beth at portugalmail.pt
 Sent: 16 November 2006 20:53
 To: vtkusers at vtk.org
 Subject: [vtkusers] Drawing a simple line graph 
 
 Hi,
  
 I'm trying to create a simple line graph. For that, I created a
polyline
 and 2 
 axis.My piece of code looks like this:
  
 // Create a polyline
  vtkPolyData* polydata = vtkPolyData::New();
  polydata->SetPoints(polyLinePoints);
  polydata->SetLines(line);
  
 // Maps it to 2D
  vtkPolyDataMapper2D *mapper = vtkPolyDataMapper2D::New();
  mapper->SetInput(polydata);
  
 // Creates an actor, defining its limits according the graph area
 defined by 
 the axes below
  vtkActor2D *actor = vtkActor2D::New();
  actor->SetMapper(mapper);
  
 
actor->GetPositionCoordinate()->SetCoordinateSystemToNormalizedViewport(
 );
  actor->GetPositionCoordinate()->SetValue(0.05, 0.2);
  
 
actor->GetPosition2Coordinate()->SetCoordinateSystemToNormalizedViewport
 (); // it's not working properly!!!
  actor->GetPosition2Coordinate()->SetValue(0.90, 0.9); // it's not
 working 
 properly!!!
  actor->GetProperty()->SetColor(1, 0, 0);
 
 // Define axes
  vtkCoordinate *coords_x1 = vtkCoordinate::New();
  coords_x1->SetValue(0.05, 0.2);
  
  vtkCoordinate *coords_x2 = vtkCoordinate::New();
  coords_x2->SetValue(0.95, 0.2);
  
  vtkCoordinate *coords_y1 = vtkCoordinate::New();
  coords_y1->SetValue(0.05, 0.2);
  
  vtkCoordinate *coords_y2 = vtkCoordinate::New();
  coords_y2->SetValue(0.05, 0.95);
  
  vtkAxisActor2D *axesX = vtkAxisActor2D::New();
  axesX->SetPoint1(coords_x1->GetValue());
  axesX->SetPoint2(coords_x2->GetValue());
  axesX->SetLabelFormat("%3.2f");
  axesX->SetFontFactor(1.2);
  axesX->SetRange(0, t); // t is the maximum x value in the polyline
 points
  axesX->SetTitle("Time (s)");
  axesX->SetNumberOfLabels(10);
  axesX->AdjustLabelsOn();
  axesX->LabelVisibilityOn();
  axesX->TickVisibilityOn();
  
  vtkAxisActor2D *axesY = vtkAxisActor2D::New();
  axesY->SetPoint1(coords_y1->GetValue());
  axesY->SetPoint2(coords_y2->GetValue());
  axesY->SetLabelFormat("%3.2f");
  axesY->SetFontFactor(1);
  axesY->SetRange(0, sCardMax); // Máximum y value in polyline points
  axesY->AdjustLabelsOn();
  axesY->LabelVisibilityOn();
  axesY->TickVisibilityOn();
  
 .....the usual stuff....creates the renderer...
  
 rw->AddActor2D(actor);
 rw->AddViewProp(axesX);
 rw->AddViewProp(axesY);
  
  
 Well, the line graph is drawn, but the problem is that axes values and
 line 
 values are not matching. 
 It seems that the GetPosition2Coordinate is not working at all, because
 the 
 mapping of the line to the graph effective area (that is defined by the
 limits 
 of the axes - xmin, ymin and xmax, ymax) is not being done. It just
puts
 the 
 polyline at the initial position defined by GetPositionCoordinate, and
 draws 
 it as the output given by the vtkPolyDataMapper2D.
  
 What should I do?
  
 Thanks for any help!
  
 Regards,
  
 Elizabeth
 
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