Hi Nyalll That's brilliant - thanka\s for taking such a detailed look at this. There are indeed several other things I need to fix but at least I an approach sorted now.
Chris ________________________________________ From: Nyall Dawson [nyall.daw...@gmail.com] Sent: 13 February 2018 18:51 To: Chris Crook Cc: firstname.lastname@example.org Subject: Re: [QGIS-Developer] QGIS3: Python QgsFeatureRenderer subclass problem On 11 February 2018 at 21:07, Chris Crook <ccr...@linz.govt.nz> wrote: > Hi Nyall > > The code is on github .. > > https://github.com/ccrook/QGIS-VectorFieldRenderer-Plugin/tree/qgis3_wip > > I've documented this in issue 8 at: > > https://github.com/ccrook/QGIS-VectorFieldRenderer-Plugin/issues/8 > > Any thoughts would be greatly appreciated :-) Ok, so the issue is that you're trying to call the base class methods by calling QgsFeatureRenderer.startRender(context,fields) That's not valid syntax. In Python 3 you should use: super().startRender(context,fields) Fixing those calls avoids the assert. ...BUT.... You'll get a lot of crashes, because there's other parts of your renderer which need upgrading to QGIS 3.0 API. And unfortunately when a renderer crashes in Python code, it segfaults after dumping the python error to the console. You'll need to run in a console to see the Python errors which are thrown and upgrade the corresponding API calls. Also - I noticed you access a layer from the project within your startRender method -- is is very unsafe for a renderer to do, since it is running in a background thread and should not be accessing layers at all. Just another thing to try to refactor out as you upgrade your plugin for 3.0! Nyall ________________________________ This message contains information, which may be in confidence and may be subject to legal privilege. If you are not the intended recipient, you must not peruse, use, disseminate, distribute or copy this message. If you have received this message in error, please notify us immediately (Phone 0800 665 463 or i...@linz.govt.nz) and destroy the original message. LINZ accepts no responsibility for changes to this email, or for any attachments, after its transmission from LINZ. Thank You. _______________________________________________ QGIS-Developer mailing list QGIS-Developer@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer