[vtkusers] bugs on Qt wiki Examples

[David Doria]

Juan,

Thank you for your interest, feedback, and offer to help! I have addressed
each of your concerns inline below:

1) For a long time ITK and VTK user, it is faster and more comfortable
> to use the examples from GIT rather than from the wiki.


I completely agree. We are working on systems that will allow working on
the examples directly through the repository.

When I got the examples from git I found two issues:
> a) The qt examples and the wiki are not in sync. At first I couldn't
> make them work, because I didn't know some files where generated from
> the .ui file, which BTW is missing from the git repo.
>

You are correct, the UI files are missing from the repository. Bill
mentioned that he will fix that shortly.


> b) The qt examples are not built by default and I did not find an easy
> way to enable them. Maybe the missing .ui file is related to this
> issue.
>

You're right, they are currently not setup to build in the repository. I
will look into doing that once the ui files are scraped nightly.


> c) either a) and b) are correct, or I am missing something. If I'm
> missing something, this means that we need a better documentation to
> make whats needed clear.
>

At the top of the Qt section (http://www.vtk.org/Wiki/VTK/Examples/Cxx#Qt)
, there is a link to "Qt Setup" (
http://www.vtk.org/Wiki/VTK/Tutorials/QtSetup) Perhaps this would be a good
place to explain the current process?


> 2) After failing with the git examples, I've fallen back to the wiki.
> Once copy/pasted everything I found out two problems:
> a) On osx with cmake 2.8.6, it will fail, because some escape
> sequences were missing. See the following post for an explanation:
> http://www.vtk.org/pipermail/vtk-developers/2012-May/011548.html.
> Using cmake 2.8.9 the problem is gone.
>

 I'm not sure there is a fix that we can do for that as it was a problem in
CMake itself?

b) The CMakeLists.txt is incorrect. The line: TARGET_LINK_LIBRARIES(
> RenderWindowUIMultipleInheritance QVTK ) does not work. I don't have
> libQVTK on any of my systems. It should read: TARGET_LINK_LIBRARIES(
> RenderWindowUIMultipleInheritance ${VTK_LIBRARIES} ${QT_LIBRARIES} )
> or at least:
> TARGET_LINK_LIBRARIES( RenderWindowUIMultipleInheritance
> ${VTK_LIBRARIES} ). I did not test the second one.
>

 QVTK was for VTK 5.x. With 6.0, you are correct that ${VTK_LIBRARIES} is
the correct thing to use. On this page:
http://www.vtk.org/Wiki/VTK/Examples/Cxx/Images/ImageSlice you can see how
we check for the condition that requires the old or new way (I suppose we
could also explicitly check the VTK version number?). If you could modify
the CMakeLists.txt files on the Qt examples pages to use QVTK or only
${VTK_LIBRARIES} conditionally that would be great.


> All those minor issues are really a stopper for a newcomer to Qt, even
> being proficient in Cmake and VTK. I'm not asking for any work, but
> offering it. I volunteer to correct those minor things. It passed some
> time since I contributed examples so I don't remember the proper way
> to correct them. Is directly the wiki the proper place?
>

Changes to the code (h/cxx) files should be done directly on the wiki. The
CMakeLists.txt files are not scraped/used in the repository, because there
is a testing framework in place that generates the necessary files to test
the examples, and those are much different from the CMakeLists.txt that a
user would need to build a single example. To modify the build system of
the examples, you should fork the repository and send a merge request.


> The cmake issue in particular, made me think about the necessity of
> adding a little readme to the each example, or at least to the whole
> wiki section. Is there a standard way to do it? Because that cmake
> issue will occur in every Qt example and putting a small notice could
> help the newcomer.
>

Perhaps we could make a MediaWiki macro called {{QT_VTKExample}} or
something similar that would post a sentence with a link to the Qt tutorial
page that I linked to earlier? This way at least this would be in a
centralized place so if we want to change what it says/links to we wouldn't
have to do it in every Qt example separately in the future.

Thanks again for your input, and let us know if you have any trouble or any
more questions.

David
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.vtk.org/pipermail/vtkusers/attachments/20121022/ad74158d/attachment.htm>