In the previous chapters, we created symbols to display vector features by instantiating one of the three basic subclasses of QgsSymbolV2:
QgsMarkerSymbolV2for point geometriesQgsLineSymbolV2for line geometriesQgsFillSymbolV2for polygon geometries
We did this either by calling one of the preceding class's static createSimple() methods, or by asking the QgsSymbolV2 class to provide us with the default symbol for a given type of geometry. Irrespective of how we did it, the result was a ready-to-use symbol object that displays a given type of vector geometry.
Internally, symbols consist of one or more symbol layers that are displayed one on top of the other, to draw the vector feature:
