[vtkusers] Rasterized output with vtkGL2PSExporter

Mon Jun 18 09:49:29 EDT 2018

Dear Roman,

As Dan mentioned improving the PDF support in Context 2D is our roadmap and
we have fairly good idea on how to get there but it may take some time
because we are still porting our code to OpenGL2 backend. If you need it
sooner, let us know and we can talk offline.

- aashish

On Mon, Jun 18, 2018 at 9:02 AM Dan Lipsa <dan.lipsa at kitware.com> wrote:

> Roman,
> Thanks for testing. Indeed, this is work in progress and we add and fix
> things as we move along with our port of cdat.
>
> Dan
>
>
> On Mon, Jun 18, 2018 at 6:18 AM Roman Hiestand <roman.hiestand at fluxim.com>
> wrote:
>
>> 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 <+41%2044%20500%2047%2070>
>>>> Fax: +41 44 500 4779 <+41%2044%20500%2047%2079>
>>>>
>>>
>>
>>
>> --
>>
>> 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 <+41%2044%20500%2047%2070>
>> Fax: +41 44 500 4779 <+41%2044%20500%2047%2079>
>>
>
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