def processAlgorithm(self, parameters, context, feedback):
source = self.parameterAsSource(parameters, self.INPUT, context)
if source is None:
raise QgsProcessingException(self.invalidSourceError(parameters, self.INPUT))
extent = self.parameterAsExtent(parameters, self.TARGET_AREA, context)
target_crs = self.parameterAsExtentCrs(parameters, self.TARGET_AREA, context)
if self.TARGET_AREA_CRS in parameters:
c = self.parameterAsCrs(parameters, self.TARGET_AREA_CRS, context)
if c.isValid():
target_crs = c
target_geom = QgsGeometry.fromRect(extent)
fields = QgsFields()
fields.append(QgsField('auth_id', QVariant.String, '', 20))
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
fields, QgsWkbTypes.NoGeometry, QgsCoordinateReferenceSystem())
if sink is None:
raise QgsProcessingException(self.invalidSinkError(parameters, self.OUTPUT))
# make intersection tests nice and fast
engine = QgsGeometry.createGeometryEngine(target_geom.constGet())
engine.prepareGeometry()
layer_bounds = QgsGeometry.fromRect(source.sourceExtent())
crses_to_check = QgsCoordinateReferenceSystem.validSrsIds()
total = 100.0 / len(crses_to_check)
found_results = 0
transform_context = QgsCoordinateTransformContext()
for current, srs_id in enumerate(crses_to_check):
if feedback.isCanceled():
break
candidate_crs = QgsCoordinateReferenceSystem.fromSrsId(srs_id)
if not candidate_crs.isValid():
continue
transform_candidate = QgsCoordinateTransform(candidate_crs, target_crs, transform_context)
transform_candidate.setBallparkTransformsAreAppropriate(True)
transform_candidate.disableFallbackOperationHandler(True)
transformed_bounds = QgsGeometry(layer_bounds)
try:
if transformed_bounds.transform(transform_candidate) != 0:
continue
except:
continue
try:
if engine.intersects(transformed_bounds.constGet()):
feedback.pushInfo(self.tr('Found candidate CRS: {}').format(candidate_crs.authid()))
f = QgsFeature(fields)
f.setAttributes([candidate_crs.authid()])
sink.addFeature(f, QgsFeatureSink.FastInsert)
found_results += 1
except:
continue
feedback.setProgress(int(current * total))
if found_results == 0:
feedback.reportError(self.tr('No matching projections found'))
return {self.OUTPUT: dest_id}
