Hi all, I am having trouble working out how to use the willRenderFeature() method of QgsFeatureRenderer classes. There have been a couple of questions related to this on gis,stackexchange.com recently, and I thought I would try to find an answer- but I've hit a dead end! The latest documentation contains a snippet specifically around dealing only with visible features: https://qgis.org/api/classQgsFeatureRenderer.html#a981b574dd6813bcc3cd849822af8929b
◆ <https://qgis.org/api/classQgsFeatureRenderer.html#a981b574dd6813bcc3cd849822af8929b> capabilities() virtual QgsFeatureRenderer::Capabilities QgsFeatureRenderer::capabilities ( ) inlinevirtual Returns details about internals of this renderer. E.g. if you only want to deal with visible features: if not renderer.capabilities().testFlag(QgsFeatureRenderer.Filter) or renderer.willRenderFeature(feature, context): deal_with_my_feature() else: skip_the_curren_feature() Reimplemented in QgsRuleBasedRenderer <https://qgis.org/api/classQgsRuleBasedRenderer.html#a1576aa5317eb1d9276f403313db68823> , QgsCategorizedSymbolRenderer <https://qgis.org/api/classQgsCategorizedSymbolRenderer.html#aed3ba97c9757f065e74f15d9aaa6cae7> , QgsPointDistanceRenderer <https://qgis.org/api/classQgsPointDistanceRenderer.html#a8ae8d6e2151b3ebb4038fec2d2bccc35> , QgsInvertedPolygonRenderer <https://qgis.org/api/classQgsInvertedPolygonRenderer.html#a389777639662b9e3e03fa5245bc802de> , QgsSingleSymbolRenderer <https://qgis.org/api/classQgsSingleSymbolRenderer.html#a6bdbfdee8d84d92168ffd2a45d2c81d8>, and QgsGraduatedSymbolRenderer <https://qgis.org/api/classQgsGraduatedSymbolRenderer.html#a7e3e3c9e1ce38d984503de720ce94297> . Definition at line 274 <https://qgis.org/api/qgsrenderer_8h_source.html#l00274> of file qgsrenderer.h <https://qgis.org/api/qgsrenderer_8h_source.html>. But I cannot work out how to implement this logic. E.g. I have a vector layer which is symbolized with a QgsCategorizedSymbolRenderer and I would like to exclude features belonging to categories which are unchecked in the TOC from, for example, an intersection test against a QgsRectangle. If I run the following in the Python console, QGIS crashes when passing a QgsRenderContext object as the second argument of the renderer.willRenderFeature() method. Firstly passing an empty instance: layer = iface.activeLayer() feat = layer.getFeature(3) renderer = layer.renderer() test = renderer.willRenderFeature(feat, QgsRenderContext()) # LINE BELOW CRASHES QGIS test = renderer.willRenderFeature(feat, QgsRenderContext()) And secondly, I tried constructing a QgsRenderContext object with the fromMapSettings() method and passing the canvas.mapSettings() to its constructor: layer = iface.activeLayer() feat = layer.getFeature(3) renderer = layer.renderer() settings = iface.mapCanvas().mapSettings() context = QgsRenderContext().fromMapSettings(settings) # LINE BELOW CRASHES QGIS test = renderer.willRenderFeature(feat, context) I'm sure I am doing something wrong because I don't have a thorough understanding of how to properly construct or use this context object. Incidentally, if I run the following line: renderer.capabilities().testFlag(QgsFeatureRenderer.Filter) I get an attribute error that Capabilities object has no attribute 'testFlag' So at this point I'm a bit stumped. Any help or guidance would be greatly appreciated. Best regards, Ben Related GIS Stack Exchange questions: https://gis.stackexchange.com/questions/350807/checking-if-feature-visible-using-pyqgis https://gis.stackexchange.com/questions/347951/selecting-only-visible-features-from-different-layers-using-pyqgis
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