[vtkusers] Rendering speed when using text labels

[David Goldsmith]

Hi, David, thanks for your reply.  Below are the "objections" to this 
strategy which have been raised locally - please reply.  Thanks!

"That would help for the nifty spinning around and all, but we found 
that  it's painfully slow even when you just do one action, and then 
wait for it to re-draw. At least that's what I thought we were seeing."

"Turning labeling on/off during rendering process ... looks like it 
shouldn't help - if you remember, it takes [a lot of] time to turn on 
[such a] large number of labels.  So it [seems like it would] change 
nothing - on 'turn labels back on' vtk will start [the] rendering 
process for the labels [and]
we approach the same problem [we are having]."

DG

David E DeMarle wrote:
> Hi David,
>
> Have you tried turning off labels while camera manipulation is 
> happening and turning them on only after a still render?
>
> hth,
> Dave DeMarle
>
>
> On 8/25/07, * David Goldsmith* <David.L.Goldsmith at noaa.gov 
> <mailto:David.L.Goldsmith at noaa.gov>> wrote:
>
>     Thanks for your reply, Berk.  We've thought of that -- you're quite
>     right that 1000 labels is pretty useless. However, we need an
>     efficient
>     way to turn the labels on and off for our use.  For example, we
>     may have
>     10,000 points, each with one or more value(s) associated with it.  Our
>     users want to see these values without having to select the points or
>     triangles (in our application, that's gonna get awfully
>     tedious).  When
>     all 10,000 points are visible, they're so close together that there is
>     no point, but when the user zooms in to get a closer view, and can see
>     perhaps 100 points, we'd like the numbers to show up next to the
>     points
>     automatically.  How might one accomplish that?  Thanks again!
>
>     DG
>
>     Berk Geveci wrote:
>     > In paraview, we decided to only show labels of selected cells/points
>     > to overcome this issue. I don't think showing more than a few dozen
>     > labels makes much sense anyway.
>     >
>     > -berk
>     >
>     > On 8/24/07, David Goldsmith <David.L.Goldsmith at noaa.gov
>     <mailto:David.L.Goldsmith at noaa.gov>> wrote:
>     >
>     >> Hello!  We're using vtk for 3-D traingular mesh visualization.  To
>     >> number label the points in the visualization, we're using
>     >> vtkLabeledDataMapper.  We're finding, however, that labeling
>     even on the
>     >> order of only 1000 points significantly slows down all
>     rendering.  Any
>     >> suggestions for how to speed things up would be greatly
>     appreciated.
>     >> Thanks!
>     >>
>     >> DG
>     >>
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