def fetch_and_apply_style(layer: QgsMapLayer,
url: str,
style_attr: str = '') -> Optional[str]:
"""
Fetches a QML style from the specified URL, and applies it to a layer.
@param layer: target layer to apply style to
@param url: URL for QML content
@param style_attr: optional str specifying name of existing field in layer to automatically
update classified references to
@return: Returns a str if an error occurred, or None if the fetch and apply was successful
"""
request = QgsBlockingNetworkRequest()
if request.get(QNetworkRequest(
QUrl(url))) != QgsBlockingNetworkRequest.NoError:
return 'Error while fetching QML style: {}'.format(
request.errorMessage())
reply = request.reply().content()
tmp_file = QTemporaryFile('{}/XXXXXX.qml'.format(QDir.tempPath()))
tmp_file.open()
tmp_file_name = tmp_file.fileName()
tmp_file.close()
with open(tmp_file_name, 'wt', encoding='utf8') as f:
f.write(reply.data().decode())
layer.loadNamedStyle(tmp_file_name)
if style_attr:
StyleUtils.update_class_attribute(layer, style_attr)
layer.triggerRepaint()
return None
def update_symbology(layer: QgsMapLayer,
color: typing.Tuple[int, int, int] = None,
size: float = None,
file: str = None) -> None:
assert layer, 'Layer is not defined'
if file:
assert isinstance(file, str)
(msg, noError) = layer.loadNamedStyle(file)
if not noError:
raise Exception(msg)
renderer = layer.renderer()
symbol = None
if isinstance(renderer, QgsSingleSymbolRenderer):
symbol = renderer.symbol()
elif isinstance(renderer, QgsGraduatedSymbolRenderer):
symbol = renderer.sourceSymbol()
else:
raise Exception('Unknown renderer!')
if color:
assert isinstance(
color, collections.abc.Sequence
), 'Color should be a iteratable of three numbers for Red, Green, Blue; Each of them between 0 and 255'
assert len(color) in (
3, 4
), 'There should be three numbers passed for Red, Green, Blue; Each of them between 0 and 255'
symbol.setColor(QColor.fromRgb(*color))
if size:
# For lines
if type(symbol) == QgsLineSymbol:
symbol.setWidth(size)
# For points
if type(symbol) == QgsMarkerSymbol:
symbol.setSize(size)
layer.triggerRepaint()
iface.layerTreeView().refreshLayerSymbology(layer.id())
