Hi,
I am trying to generate a proportional symbol symbology using data
defined symbol size in a QGIS 3 python plugin.
Here is the working code :
# Symbol creation
symbolLayer = QgsSimpleMarkerSymbolLayer()
symbolLayer.setShape(QgsSimpleMarkerSymbolLayer.Circle)
symbolLayer.setSize(2.0)
symbolLayer.setColor(QColor(31, 120, 180)
symbolLayer.setStrokeColor(QColor(255, 255, 255)
symbolLayer.setStrokeWidth(0.4)
symbol = QgsMarkerSymbol.createSimple({})
symbol.changeSymbolLayer(0, symbolLayer)
# Size definition (Flannery method)
# layer is a QgsSingleSymbolRenderer
strExp = 'coalesce(scale_exp("value", 0.0, 150, 1, 20, 0.57), 0)'
symbol.setDataDefinedSize(QgsProperty.fromExpression(strExp))
layer.renderer().setSymbol(symbol)
The problem is the legend. This code :
# Legend
lgd = QgsDataDefinedSizeLegend()
lgd.setLegendType(QgsDataDefinedSizeLegend.LegendCollapsed)
lgd.setClasses([
QgsDataDefinedSizeLegend.SizeClass(150, '150'),
QgsDataDefinedSizeLegend.SizeClass(75, '75'),
QgsDataDefinedSizeLegend.SizeClass(15, '15')
])
layer.renderer().setDataDefinedSizeLegend(lgd)
produces an enormous legend symbol :
https://i.stack.imgur.com/xvTgU.png
However, if I open the layer properties dialog and update parameters
with datadefined size assistant, the legend is refreshed with the
correct size :
https://i.stack.imgur.com/h3Ok2.png
What am I missing ?
Thanks for any hint,
--
Christophe Damour
_______________________________________________
QGIS-Developer mailing list
[email protected]
List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer
