[vtkusers] Problem rendering vtkChartXY

[Riku]

Eric,

Ouch, that was an easy one. Thank you! The font sizing etc. works fine
with minimal changes to my code. I must have been blind before, and
managed to revert to the automatic settings. I respond here to give a
hint for others about the resolution of that particular problem. I had
the same problem for the legend settings (of course), and got that
resolved in the same way.

I hope we'll have some ideas about the unexpected behaviour of the
vtkWindowToImageFilter for Charts.

Riku

On 7 March 2011 17:25, Eric E. Monson <emonson at cs.duke.edu> wrote:
> Hey Riku,
>
> I had never tried this before, but I see the same behavior. It is strange because as far as I can see, ParaView also uses vtkWindowToImageFilter to create a screen shot of the chart views, but it works there...
>
> Regarding the font size and tick spacing, you can get around this problem in a manual way by specifying the tick positions and labels and their font sizes. vtkAxis has SetTickPositions() and SetTickLabels(), both of which internally set Behavior = 2 (CUSTOM), which turns off automatic tick spacing calculations. Then you can use GetLabelProperties() to set the font size to a reasonable one for the image size you want. It's not a very automatic solution, but it gets around the problem.
>
> Maybe the main Charts developer, Marcus, will have a chance to chime in on why the image tiling for vtkWindowToImageFilter works for the Charts in ParaView but not in straight VTK.
>
> -Eric
>
> · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·
> Eric E Monson
> Duke Visualization Technology Group
>
>
> On Mar 7, 2011, at 9:59 AM, Riku wrote:
>
>> Hello,
>>
>> I am presently using the vtkChartXY class (and related) to plot simple
>> X/Y plots. As I want to hardcopy them, I use the commonly described
>> method and pass the render window to a window to image filter, and
>> then on to a PNG writer. This works great for (more complicated)
>> visualizations I do, but vtkChartXY gives me problems.
>>
>> At a resolution (i.e. render window size) of 600x600, for example, the
>> resulting image is grainy and generally unsuitable for printing. The
>> solution I've used is to set the render window size to something like
>> 2000x2000 instead.
>>
>> The problem: On Windows, I have to use the SetMagnification() trick to
>> get the image size right (as my screen size is smaller than
>> 2000x2000), but for some reason I cannot get it to work for the
>> rendered vtkChartXY plots. The resulting images are broken up, mixed,
>> skewed and generally weird. What can I do about this?
>>
>> Moreover, If I set the render window size close to my screen's maximum
>> size, all text scales with the plot and thus becomes too small for the
>> plot. I cannot find any way to change this behaviour. Is there any
>> way? For other rendering situations I have not had this issue.
>>
>> The problem can be recreated with the example here:
>> http://www.vtk.org/Wiki/VTK/Examples/Cxx/Plotting/LinePlot
>> (Add render window --> window to image filter --> png writer, and set
>> render window size to something large.)
>>
>> Thanks for any help or suggestions,
>>
>> Riku
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