[vtk-developers] Bug in vtkColorTransferFunction

[Randall Hand]

Looks good to me.

On 12/7/05, David Cole <david.cole at kitware.com> wrote:
>
> This was checked in to the VTK-5-0 branch on Dec. 5. Randall, could you
> update and verify that it's fixed...?
>
> Thanks,
> David
>
>
> Randall Hand wrote:
>
> > I've spent the last week beating my head against the wall trying to
> > figure out why my colormap didn't work in my application, but smaller
> > test cases would work.  I finally figured it out just now.  (Filed as
> > bug 2546)
> >
> > When using a vtkColorTransferFunction, and adding a large number of
> > points (Over 100) in an out-of-order fashion (In my case, I'm reading
> > them from a file and the X's are fairly random, not simply
> > incrementing), it will destroy the colormap.  The problem comes when
> > you add the 100'th point and it tries to resize the colormap.  In this
> > case, it uses a memcpy to copy the colormap into the newly allocated
> > (and large) array.  If that 100th's point is not the highest point in
> > the list, it uses 2 memcpy's, one shifted by one entry to create a
> > "hole" for the newly added entry in the middle.  Unfortunately, it
> > indexes wrong! So the net result:  Blue becomes red, green becomes
> > blue, red becomes the next entry's X, and in general it's just all
> > b0rked.
> >
> > Attached to the bug (
> > http://www.vtk.org/Bug/bug.php?op=show&bugid=2546&pos=3
> > <http://www.vtk.org/Bug/bug.php?op=show&bugid=2546&pos=3> ) you'll
> > find a test-case that uses a Mandelbrot fractal source to illustrate
> > the problem.
> >
> > --
> > Randall Hand
> > Visualization Scientist,
> > ERDC-MSRC Vicksburg, MS
> > Homepage: http://www.yeraze.com
> >
> >------------------------------------------------------------------------
> >
> >_______________________________________________
> >vtk-developers mailing list
> >vtk-developers at vtk.org
> >http://www.vtk.org/mailman/listinfo/vtk-developers
> >
> >
>



--
Randall Hand
Visualization Scientist,
ERDC-MSRC Vicksburg, MS
Homepage: http://www.yeraze.com
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