Python QgsRendererV2Widget not displaying on Windows 64 build

[qgib]

Author Name: Chris Crook (@ccrook) Original Redmine Issue: 8646 Affected QGIS version: 2.4.0 Redmine category:python_plugins

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I maintain the VectorFieldRenderer widget, which implements a python custom renderer. The QGIS 2.0 version is working on Ubuntu, but on windows 64 (using standalone installer), when the renderer is selected in the Properties | Style dialog, the renderer configuration widget is not displayed, and instead there is just a message "This renderer doesn't implement a graphical interface".

I've build a minimal custom renderer (attached as LayerTest.zip), and that behaves in the same way, so I suspect that there is an issue in 64bit build (note - I haven't tested other windows builds).

Steps to replicate: 1) Install attached LayerTest plugin to /.qgis2/python/plugins 2) Start QGIS 3) Open plugin manager and enable LayerTest plugin 4) Create a new point vector layer 5) Make the new layer the current layer and open the Style tab of the layer Properties dialog 6) Select the LayerTest renderer type

The dialog box should show "Dummy widget for layer ".

It does this on ubuntu 12.04. On windows 64bit build it displays the error message above (This renderer doesn't implement a graphical interface).

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• LayerTest.zip (Chris Crook)

[qgib]

Author Name: Anónimo (Anónimo)

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Fixed in changeset "86ddc49acf3599e6d959f462da1d870dd6ba148d".

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• status_id was changed from Open to Closed

[qgib]

Author Name: Matthias Kuhn (@m-kuhn)

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Hi, can somebody verify, if this really solves the issue and re-open if appropriate?

And thanks to @mbernasocchi for finding this solution.

[qgib]

Author Name: Chris Crook (@ccrook)

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Subtle indeed - great work. ATM I don't have a windows build environment, so can't confirm. But, in anticipation of this resolving the issue, thanks!

[qgib]

Author Name: Andy Aschwanden (Andy Aschwanden)

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Hi,

While I was trying to use the VectorFieldRenderer widget mentioned above, I've noticed that this issue still exists on QGIS 7c98970 (nightly build from http://qgis.dakotacarto.com/, Mac OS X 10.8.5). I've also tested the minimal example in TestLayer.zip, with the same result, it shows

"This renderer doesn't implement a graphical interface"

Thanks.

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• status_id was changed from Closed to Reopened

[qgib]

Author Name: Paolo Cavallini (@pcav)

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• fixed_version_id was changed from Version 2.0.0 to Future Release - High Priority

[qgib]

Author Name: Chris Crook (@ccrook)

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Still seems to be an issue in version 2.4 on Windows 64bit

[qgib]

Author Name: Chris Crook (@ccrook)

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• version was changed from 2.0.1 to 2.4.0

[qgib]

Author Name: Chris Crook (@ccrook)

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I've just upgraded Ubuntu to version 14.04 and this issue is now present on Ubuntu as well. So it occurs in 64 bit environments generally - windows, ubuntu, mac. This occurs both in the released version and building from source. I assume that this is due to a new version of SIP with the Ubuntu version upgrade.

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• operating_system was changed from Windows to All
• priority_id was changed from Normal to High

[qgib]

Author Name: Chris Crook (@ccrook)

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The underlying issue relates to python subclasses of C++ classes. When the python object is saved in C++ code (eg in a registry), it loses the python bindings to methods that are over-ridden in the python class- they are not used when the object is called from C++, and instead the C++ base class implementations of the methods are used.

This means that python implementations of C++ base classes (renderers, custom layers, etc) will generally not work.

[qgib]

Author Name: Chris Crook (@ccrook)

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• os_version was changed from 7 (64 bit) to 64 bit

[qgib]

Author Name: Jürgen Fischer (@jef-n)

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Despite the @/Transfer/@ annotation on @QgsRendererV2Registry::addRenderer@ the @LayerMetadata@ instance is deleted. If the metadata is assigned to a member variable of @Plugin@ to avoid it's destruction the GUI page appears.

[qgib]

Author Name: Jürgen Fischer (@jef-n)

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• priority_id was changed from High to Normal

[qgib]

Author Name: Jürgen Fischer (@jef-n)

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• category_id was changed from Build/Install to Python plugins

[qgib]

Author Name: Giovanni Manghi (@gioman)

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• regression was configured as 0
• easy_fix was configured as 0

[qgib]

Author Name: Giovanni Manghi (@gioman)

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End of life notice: QGIS 2.18 LTR

Source: http://blog.qgis.org/2019/03/09/end-of-life-notice-qgis-2-18-ltr/

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• resolution was changed from to end of life
• status_id was changed from Reopened to Closed