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February 10, 2021 15:40
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| """ | |
| POC from https://gis.stackexchange.com/questions/385525/qgis-how-to-invert-the-values-in-a-layout-legend/386746?noredirect=1#comment633627_386746 | |
| Based on Ben W answer | |
| Does not work for every legend | |
| """ | |
| class InvertStyleConfigWidget(QgsMapLayerConfigWidget): | |
| """ | |
| Emulates the QGS Layer Property Dialogs "Information" page | |
| """ | |
| def __init__(self, layer: QgsMapLayer, canvas: QgsMapCanvas, parent=None): | |
| super().__init__(layer, canvas, parent=parent) | |
| self.setLayout(QVBoxLayout()) | |
| self.invertButton : QPushButton = QPushButton('Invert legend') | |
| self.layer = layer | |
| self.layout().addWidget(self.invertButton) | |
| self.layout().setAlignment(Qt.AlignTop) | |
| self.invertButton.clicked.connect(self.invert_legend) | |
| def invert_legend(self): | |
| root = QgsProject.instance().layerTreeRoot() | |
| model = QgsLegendModel(root) | |
| layer_node=root.findLayer( self.layer.id()) | |
| view_model = iface.layerTreeView().layerTreeModel() | |
| order_property = layer_node.customProperty('legend/node-order') | |
| if order_property: | |
| current_order = [ int(i) for i in order_property.split(',')] | |
| else: | |
| current_order = [ int(i) for i in range(model.legendRootRowCount(layer_node))] | |
| QgsMapLayerLegendUtils.setLegendNodeOrder(layer_node, current_order[::-1]) | |
| view_model.refreshLayerLegend(layer_node) | |
| def shouldTriggerLayerRepaint(self): | |
| return False | |
| def apply(self): | |
| pass | |
| class InvertStyleConfigWidgetFactory(QgsMapLayerConfigWidgetFactory): | |
| def __init__(self, title='Invert Legend', icon=QIcon(':images/themes/default/mActionSharingImport.svg')): | |
| super(InvertStyleConfigWidgetFactory, self).__init__(title, icon) | |
| self.setSupportLayerPropertiesDialog(True) | |
| self.setSupportsStyleDock(True) | |
| def createWidget(self, layer, canvas, dockWidget=False, parent=None): | |
| return InvertStyleConfigWidget(layer, canvas, parent=parent) | |
| def supportLayerPropertiesDialog(self): | |
| """For some reasons it does not work with raster layer""" | |
| return True | |
| def supportsStyleDock(self): | |
| return True | |
| def supportsLayer(self, layer): | |
| return True | |
| #iface.unregisterMapLayerConfigWidgetFactory(factory) | |
| factory = InvertStyleConfigWidgetFactory() | |
| iface.registerMapLayerConfigWidgetFactory(factory) |
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Hi @jdlom,
Just letting you know that I have discovered an annoying issue which is apparently caused by setting a legend node order on a QgsLayerTreeLayer in the main layer tree view. After setting a new node order on a layer with e.g. 5 nodes, if you then go back into the symbology dialog and increase the number of classes and apply the new render settings, only 5 nodes are shown in the legend! One must either manually run: QgsMapLayerLegendUtils.setLegendNodeOrder(layer_node, ...) and pass an order list which contains the new number of nodes or remove and reload the layer. I have searched but not yet found a simple solution. It seems that in the source code, this method is only used on layout legends. For the time being, I have removed the part in my stack exchange answer about updating the TOC.
Regards