<div class="gmail_quote">On Wed, Jan 26, 2011 at 5:33 AM, Steffen Oeltze <span dir="ltr"><<a href="mailto:stoeltze@isg.cs.uni-magdeburg.de">stoeltze@isg.cs.uni-magdeburg.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div bgcolor="#ffffff" text="#000000">
Hi,<div><div></div><div class="h5"><br>
<br>
<blockquote type="cite">
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204, 204, 204);padding-left:1ex">
<div bgcolor="#ffffff" text="#000000">
<blockquote type="cite">
<div class="gmail_quote">
<div>
<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204, 204, 204);padding-left:1ex">DearAll,<br>
<br>
I plan to evaluate VTK for graph visualization and I
wonder whether it provides the features listed
below.<br>
For some features, I already found information
online.<br>
</blockquote>
<div> </div>
</div>
<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204, 204, 204);padding-left:1ex"> - modifying the edge
thickness/width according to some edge weight (???)<br>
</blockquote>
<div>
<div><br>
</div>
<div>Not currently possible. To stress certain edges I
normally use a color map for edges that changes
their opacity based on the weight.</div>
<div><br>
</div>
</div>
</div>
</blockquote>
Using the opacity is also a good idea. However, I just
discovered the vtkGraphToPolyData class which should provide
access to the edge geometry. Maybe, by using, e.g.,
vtkRibbonFilter, I will be able to change the edge width? I
wonder how this would influence the edge picking in the
view.<br>
</div>
</blockquote>
<div><br>
</div>
<div>Absolutely. If you want to use the lower-level filters like
vtkGraphToPolyData, all sorts of other opportunities open up.
Ribbons or tubes could be used to change the width based on a
metric. But you are correct that then you don't get picking
for free like you do in vtkGraphLayoutView. As long as you
have a cell or point data array that indicates which edge the
geometry came from, you should be able to use the picker
classes in VTK without too much trouble.</div>
</div>
</blockquote>
<br></div></div>
I toyed around a bit with the above mentioned ribbons and tubes.
However, I was wondering if there is a more simple method to replace
lines as edges by my own 2D primitive. For example, would it be
possible to derive my own class from the class that draws the graph
and then, overwrite the method that does the actual painting? So
far, I was not able to find the class that does the line drawing in
the graph but I discovered a promising example:
<a href="http://vtk.org/gitweb?p=VTK.git;a=blob;f=Examples/Charts/Cxx/vtkGraphItem.cxx" target="_blank">http://vtk.org/gitweb?p=VTK.git;a=blob;f=Examples/Charts/Cxx/vtkGraphItem.cxx</a>
(Paint()-function). Any thoughts on that are very welcome.<br></div></blockquote><div><br></div><meta charset="utf-8">Yes, this is the way to go for totally customized 2D rendering. Feel free to use that as a starting point. Longer term, we may want a new general-purpose graph view that uses this newer 2D rendering engine. This is the engine that powers all the new charting classes.</div>
<div class="gmail_quote"><br></div><div class="gmail_quote">Jeff<br><br></div>-- <br>Jeff Baumes, Ph.D.<br>Technical Lead, Kitware Inc.<br>(518) 881-4932<br>