Modifying the texture/fill of a vector layer in PyQGIS

Question

Currently I am writing a standalone Python script to modify a few vector layers to have a wine fill pattern inside. The geometry I am working with is a polygon. I am aware of how to change outline colors and simple fill colors; but, does anyone happen to know how to add a pattern inside the polygon?

Answer 1

Start with:

symbol = QgsSymbolV2.defaultSymbol(layer.geometryType())
renderer = QgsSingleSymbolRendererV2(symbol)

Now you have 10 types of fill:

• Simple fill, QgsSimpleFillSymbolLayerV2
• Gradient fill, QgsGradientFillSymbolLayerV2
• Centroid fill, QgsCentroidFillSymbolLayerV2
• Line pattern fill, QgsLinePatternFillSymbolLayer
• Point pattern fill, QgsPointPatternFillSymbolLayer
• SVG fill, QgsSVGFillSymbolLayer
• Outline: marker line, QgsMarkerLineSymbolLayerV2
• Outline: simple line, QgsSimpleLineSymbolLayerV2
• Shapeburst fill, QgsShapeburstFillSymbolLayerV2
• Raster fill, QgsRasterFillSymbolLayer

So for simple fill it will be:

symbol_layer = QgsSimpleFillSymbolLayerV2.create(properties)

properties is a dictionary {'color':'red', 'style': 'f_diagonal', ...} so here you can choose proper 'style' parameter. If you don know nothing about parameters you can style your layer in QGIS, export this style to .qml file, and check proper tags for keywords. They are the same as in pyqgis.

renderer.symbols()[0].changeSymbolLayer(0, symbol_layer)
layer.setRendererV2(renderer)