[vtkusers] Rasterized output with vtkGL2PSExporter

[Roman Hiestand]

I tried your suggestion, but after some testing I found that the exported
SVG/PDF does not contain the vtkPolyData. I assume it is because it's not
yet implemented:

https://gitlab.kitware.com/vtk/vtk/blob/master/Rendering/ContextOpenGL2/vtkOpenGLContextDevice2D.cxx#L1853

Another issue I am having is that I would like to draw the cells in
vtkPolyData as wireframe, which does not seem to be supported directly. I
could convert the cells to lines myself, however.

But thanks for your tips and suggestions, I appreciate your help very much!


On Fri, Jun 15, 2018 at 2:59 PM, Dan Lipsa <dan.lipsa at kitware.com> wrote:

> Context2D should support vtkPolyData. See the following commit.
>
> commit 1469ea5dcb33d69710ed4099789ebc0fa2bcdf57
>
> Author: Alvaro Sanchez <alvaro.sanchez at kitware.com>
>
> Date:   Mon Oct 17 19:00:43 2016 -0400
>
>
>     Added support for vtkPolyData in vtkContext2D.
>
>
>
>     vtkContext2D takes a new type of item which directly draws a 2D mesh
>
>     represented by a vtkPolyData object. Internally, vtkContextDevice2D
> makes
>
>     the API calls necessary to draw the internal primitives of
> vtkPolyData.
>
>     Added a test demonstrating the use of vtkPolyDataItem.
>
>
>
>     Added interaction and batched primitives for drawing.
>
>
>
>     vtkInteractiveArea derives from vtkContextArea and implements basic
> interaction
>
>     (zoom and panning). Currently, two types of vtkPolyData primitives
> are supported,
>
>     Lines and Polygons. Lines are batched and drawn using
> ContextDevice2D::DrawLines.
>
>     Polygons are first decomposed into a set of triangles and then drawn
> using
>
>     ContextDevice2D::CoreDrawTriangles. Primitives are colored per vertex.
>
>
>
>     Suppressed run-time warning.
>
>
>
>     Setting the current renderer in the interactor style. Removed
>
>     unecessary initializations.
>
>
>
>     Using defined symbolic names for scalar modes.
>
>
> On Fri, Jun 15, 2018 at 5:02 AM Roman Hiestand <roman.hiestand at fluxim.com>
> wrote:
>
>> Dan,
>>
>> Thank you for the information! I assume there is no mapper from
>> vtkPolyData to vtkContext2D? At least I didn't find one.
>> Migrating our code to vtkContext2D would be too tedious, so for now we
>> stick to the current solution. If we need a better SVG/PDF output, we will
>> use either Qt or a specialized library like cairo.
>>
>> Regards
>> Roman
>>
>>
>> On Thu, Jun 14, 2018 at 5:39 PM, Dan Lipsa <dan.lipsa at kitware.com> wrote:
>>
>>> Roman,
>>> For the new OpenGL2 backend only 2D polygon data drawn within a
>>> vtkContext2D can be exported as vector data in a PDF or SVG. This is
>>> because GL2PS uses a feature removed from recent OpenGL versions
>>> (glFeedbackBuffer). So, if exporting vector data is important to your
>>> application you'll have to port it to draw everything inside a vtkContext2D
>>> class. We are currently doing this port for the cdat.
>>>
>>>
>>> On Thu, Jun 14, 2018 at 11:16 AM Roman Hiestand <
>>> roman.hiestand at fluxim.com> wrote:
>>>
>>>> Hello
>>>>
>>>> Since upgrading to VTK 8.1.1 and using the OpenGL2 backend I have
>>>> noticed that when exporting to vector graphics formats such as PDF and SVG
>>>> using vtkGL2PSExporter a large part of the scene is rasterized.
>>>> I have a 2D scene with a vtkPolyDataMapper and some axis
>>>> (vtkCubeAxesActor2D), the camera is set to parallel projection.
>>>> When I try to export the scene to PDF or SVG using vtkGL2PSExporter the
>>>> vtkPolyData is rasterized, while the axis (including labels etc) is
>>>> exported in vector graphics.
>>>>
>>>> I tried fiddling around with the parameters of vtkGL2PSExporter, but I
>>>> wasn't able to achieve all-vector-graphics like with VTK 8.0 and (old)
>>>> OpenGL backend.
>>>>
>>>> Has anyone a clue how to create a non-rasterized output? When debugging
>>>> the code, I saw that vtkGL2PSExporter rasterizes the background, but why is
>>>> the vtkPolyDataMapper considered to be background?
>>>>
>>>> I also tried exporting the same vtkPolyData with ParaView (5.5.1 64bit
>>>> Windows) to PDF or SVG, and I have the same effect there, the polydata is
>>>> rasterized.
>>>>
>>>> Regards
>>>> Roman
>>>>
>>>>
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>>
>>
>> --
>>
>> Fluxim AG
>> Roman Hiestand
>> Katharina-Sulzer-Platz 2
>> <https://maps.google.com/?q=Katharina-Sulzer-Platz+2+8406+Winterthur+Switzerland&entry=gmail&source=g>
>> 8406 Winterthur
>> <https://maps.google.com/?q=Katharina-Sulzer-Platz+2+8406+Winterthur+Switzerland&entry=gmail&source=g>
>> Switzerland
>> <https://maps.google.com/?q=Katharina-Sulzer-Platz+2+8406+Winterthur+Switzerland&entry=gmail&source=g>
>>
>>
>> www.fluxim.com
>> Email: roman.hiestand at fluxim.com
>> Phone: +41 44 500 4770
>> Fax: +41 44 500 4779
>>
>


-- 

Fluxim AG
Roman Hiestand
Katharina-Sulzer-Platz 2
8406 Winterthur
Switzerland


www.fluxim.com
Email: roman.hiestand at fluxim.com
Phone: +41 44 500 4770
Fax: +41 44 500 4779
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