@@ -60,77 +60,88 @@ def defineCharacteristics(self):
6060 self .addOutput (OutputVector (Clip .OUTPUT , self .tr ('Clipped' )))
6161
6262 def processAlgorithm (self , progress ):
63- layerA = dataobjects .getObjectFromUri (
63+ source_layer = dataobjects .getObjectFromUri (
6464 self .getParameterValue (Clip .INPUT ))
65- layerB = dataobjects .getObjectFromUri (
65+ mask_layer = dataobjects .getObjectFromUri (
6666 self .getParameterValue (Clip .OVERLAY ))
6767
6868 writer = self .getOutputFromName (self .OUTPUT ).getVectorWriter (
69- layerA .pendingFields (),
70- layerA .dataProvider ().geometryType (),
71- layerA .dataProvider ().crs ())
72-
73- inFeatA = QgsFeature ()
74- inFeatB = QgsFeature ()
75- outFeat = QgsFeature ()
76-
77- index = vector .spatialindex (layerB )
78-
79- selectionA = vector .features (layerA )
80-
81- total = 100.0 / len (selectionA )
82-
83- for current , inFeatA in enumerate (selectionA ):
84- geom = inFeatA .geometry ()
85- attrs = inFeatA .attributes ()
86- intersects = index .intersects (geom .boundingBox ())
87- first = True
88- found = False
89- if len (intersects ) > 0 :
90- for i in intersects :
91- layerB .getFeatures (
92- QgsFeatureRequest ().setFilterFid (i )).nextFeature (
93- inFeatB )
94- tmpGeom = inFeatB .geometry ()
95- if tmpGeom .intersects (geom ):
96- found = True
97- if first :
98- outFeat .setGeometry (QgsGeometry (tmpGeom ))
99- first = False
100- else :
101- cur_geom = outFeat .geometry ()
102- new_geom = QgsGeometry (cur_geom .combine (tmpGeom ))
103- if new_geom .isEmpty () or new_geom .isGeosEmpty () or not new_geom .isGeosValid ():
104- ProcessingLog .addToLog (ProcessingLog .LOG_ERROR ,
105- self .tr ('GEOS geoprocessing error: One or '
106- 'more input features have invalid '
107- 'geometry.' ))
108- break
109-
110- outFeat .setGeometry (QgsGeometry (new_geom ))
111- if found :
112- cur_geom = outFeat .geometry ()
113- new_geom = QgsGeometry (geom .intersection (cur_geom ))
69+ source_layer .fields (),
70+ source_layer .dataProvider ().geometryType (),
71+ source_layer .crs ())
72+
73+ # first build up a list of clip geometries
74+ clip_geoms = []
75+ for maskFeat in vector .features (mask_layer , QgsFeatureRequest ().setSubsetOfAttributes ([])):
76+ clip_geoms .append (maskFeat .geometry ())
77+
78+ # are we clipping against a single feature? if so, we can show finer progress reports
79+ if len (clip_geoms ) > 1 :
80+ combined_clip_geom = QgsGeometry .unaryUnion (clip_geoms )
81+ single_clip_feature = False
82+ else :
83+ combined_clip_geom = clip_geoms [0 ]
84+ single_clip_feature = True
85+
86+ # use prepared geometries for faster intersection tests
87+ engine = QgsGeometry .createGeometryEngine (combined_clip_geom .geometry ())
88+ engine .prepareGeometry ()
89+
90+ tested_feature_ids = set ()
91+
92+ for i , clip_geom in enumerate (clip_geoms ):
93+ input_features = [f for f in vector .features (source_layer , QgsFeatureRequest ().setFilterRect (clip_geom .boundingBox ()))]
94+
95+ if single_clip_feature :
96+ total = 100.0 / len (input_features )
97+ else :
98+ total = 0
99+
100+ for current , in_feat in enumerate (input_features ):
101+ if not in_feat .geometry ():
102+ continue
103+
104+ if in_feat .id () in tested_feature_ids :
105+ # don't retest a feature we have already checked
106+ continue
107+
108+ tested_feature_ids .add (in_feat .id ())
109+
110+ if not engine .intersects (in_feat .geometry ().geometry ()):
111+ continue
112+
113+ if not engine .contains (in_feat .geometry ().geometry ()):
114+ cur_geom = in_feat .geometry ()
115+ new_geom = combined_clip_geom .intersection (cur_geom )
114116 if new_geom .wkbType () == Qgis .WKBUnknown or QgsWKBTypes .flatType (new_geom .geometry ().wkbType ()) == QgsWKBTypes .GeometryCollection :
115- int_com = QgsGeometry ( geom .combine (cur_geom ) )
116- int_sym = QgsGeometry ( geom .symDifference (cur_geom ) )
117- new_geom = QgsGeometry ( int_com .difference (int_sym ) )
117+ int_com = in_feat . geometry () .combine (new_geom )
118+ int_sym = in_feat . geometry () .symDifference (new_geom )
119+ new_geom = int_com .difference (int_sym )
118120 if new_geom .isGeosEmpty () or not new_geom .isGeosValid ():
119121 ProcessingLog .addToLog (ProcessingLog .LOG_ERROR ,
120122 self .tr ('GEOS geoprocessing error: One or more '
121123 'input features have invalid geometry.' ))
122- continue
123- try :
124- outFeat .setGeometry (new_geom )
125- outFeat .setAttributes (attrs )
126- writer .addFeature (outFeat )
127- except :
128- ProcessingLog .addToLog (ProcessingLog .LOG_ERROR ,
129- self .tr ('Feature geometry error: One or more '
130- 'output features ignored due to '
131- 'invalid geometry.' ))
132- continue
133-
134- progress .setPercentage (int (current * total ))
124+ else :
125+ # clip geometry totally contains feature geometry, so no need to perform intersection
126+ new_geom = in_feat .geometry ()
127+
128+ try :
129+ out_feat = QgsFeature ()
130+ out_feat .setGeometry (new_geom )
131+ out_feat .setAttributes (in_feat .attributes ())
132+ writer .addFeature (out_feat )
133+ except :
134+ ProcessingLog .addToLog (ProcessingLog .LOG_ERROR ,
135+ self .tr ('Feature geometry error: One or more '
136+ 'output features ignored due to '
137+ 'invalid geometry.' ))
138+ continue
139+
140+ if single_clip_feature :
141+ progress .setPercentage (int (current * total ))
142+
143+ if not single_clip_feature :
144+ # coarse progress report for multiple clip geometries
145+ progress .setPercentage (100.0 * i / len (clip_geoms ))
135146
136147 del writer
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