def big_marker_preview_image(symbol: QgsSymbol,
expression_context: Optional[QgsExpressionContext] = None) -> QImage:
"""
Generate a big symbol preview image for a marker
"""
preview = QImage(QSize(100, 100), QImage.Format_ARGB32_Premultiplied)
preview.fill(0)
p = QPainter(preview)
p.setRenderHint(QPainter.Antialiasing)
p.translate(0.5, 0.5)
context = QgsRenderContext.fromQPainter(p)
try:
context.setFlag(QgsRenderContext.RenderSymbolPreview)
except AttributeError:
pass
if expression_context:
context.setExpressionContext(expression_context)
try:
context.setIsGuiPreview(True)
except AttributeError:
pass
symbol.startRender(context)
symbol.renderPoint(QPointF(50, 50), None, context)
symbol.stopRender(context)
return preview
