review Difference tool

python/plugins/sextante/algs/ftools/Difference.py

@@ -22,90 +22,93 @@
 # This will get replaced with a git SHA1 when you do a git archive
 __revision__ = '$Format:%H$'
 
-
 from PyQt4.QtCore import *
-from PyQt4.QtGui import *
+
 from qgis.core import *
-from sextante.parameters.ParameterVector import ParameterVector
+
 from sextante.core.QGisLayers import QGisLayers
-from sextante.outputs.OutputVector import OutputVector
-from sextante.algs.ftools import FToolsUtils as utils
 from sextante.core.SextanteLog import SextanteLog
 from sextante.core.GeoAlgorithm import GeoAlgorithm
 
+from sextante.parameters.ParameterVector import ParameterVector
+
+from sextante.outputs.OutputVector import OutputVector
+
+from sextante.algs.ftools import FToolsUtils as utils
 
 class Difference(GeoAlgorithm):
 
     INPUT = "INPUT"
-    INPUT2 = "INPUT2"
+    OVERLAY = "OVERLAY"
     OUTPUT = "OUTPUT"
 
     #===========================================================================
     # def getIcon(self):
     #    return QtGui.QIcon(os.path.dirname(__file__) + "/icons/difference.png")
     #===========================================================================
 
+    def defineCharacteristics(self):
+        self.name = "Difference"
+        self.group = "Vector overlay tools"
+        self.addParameter(ParameterVector(Difference.INPUT, "Input layer", ParameterVector.VECTOR_TYPE_ANY))
+        self.addParameter(ParameterVector(Difference.OVERLAY, "Difference layer", ParameterVector.VECTOR_TYPE_ANY))
+        self.addOutput(OutputVector(Difference.OUTPUT, "Difference"))
+
     def processAlgorithm(self, progress):
-        vlayerA = QGisLayers.getObjectFromUri(self.getParameterValue(Difference.INPUT))
-        vlayerB = QGisLayers.getObjectFromUri(self.getParameterValue(Difference.INPUT2))
+        layerA = QGisLayers.getObjectFromUri(self.getParameterValue(Difference.INPUT))
+        layerB = QGisLayers.getObjectFromUri(self.getParameterValue(Difference.OVERLAY))
+
         GEOS_EXCEPT = True
+
         FEATURE_EXCEPT = True
-        vproviderA = vlayerA.dataProvider()
-        vproviderB = vlayerB.dataProvider()
-        fields = vproviderA.fields()
-        # check for crs compatibility
-        crsA = vproviderA.crs()
-        crsB = vproviderB.crs()
-        if not crsA.isValid() or not crsB.isValid():
-            SextanteLog.addToLog(SextanteLog.LOG_WARNING, "Difference. Invalid CRS. Results might be unexpected")
-        else:
-            if crsA != crsB:
-                SextanteLog.addToLog(SextanteLog.LOG_WARNING, "Difference. Non-matching CRSs. Results might be unexpected")
-        writer = self.getOutputFromName(Difference.OUTPUT).getVectorWriter(fields, vproviderA.geometryType(), vproviderA.crs() )
+
+        writer = self.getOutputFromName(Difference.OUTPUT).getVectorWriter(layerA.pendingFields(),
+                     layerA.dataProvider().geometryType(), layerA.dataProvider().crs())
+
         inFeatA = QgsFeature()
         inFeatB = QgsFeature()
         outFeat = QgsFeature()
-        index = utils.createSpatialIndex(vlayerB)
-        nElement = 0
-        selectionA = QGisLayers.features(vlayerA)
-        nFeat = len(selectionA)
+
+        index = utils.createSpatialIndex(layerB)
+
+        selectionA = QGisLayers.features(layerA)
+
+        current = 0
+        total = 100.0 / float(len(selectionA))
+
         for inFeatA in selectionA:
-            nElement += 1
-            progress.setPercentage(nElement/float(nFeat) * 100)
             add = True
-            geom = QgsGeometry( inFeatA.geometry() )
-            diff_geom = QgsGeometry( geom )
-            atMap = inFeatA.attributes()
-            intersects = index.intersects( geom.boundingBox() )
-            for id in intersects:
-                vlayerB.featureAtId( int( id ), inFeatB , True)
-                tmpGeom = QgsGeometry( inFeatB.geometry() )
+            geom = QgsGeometry(inFeatA.geometry())
+            diff_geom = QgsGeometry(geom)
+            attrs = inFeatA.attributes()
+            intersections = index.intersects(geom.boundingBox())
+            for i in intersections:
+                request = QgsFeatureRequest().setFilterFid(i)
+                inFeatB = layerB.getFeatures(request).next()
+                tmpGeom = QgsGeometry(inFeatB.geometry())
                 try:
-                    if diff_geom.intersects( tmpGeom ):
-                        diff_geom = QgsGeometry( diff_geom.difference( tmpGeom ) )
+                    if diff_geom.intersects(tmpGeom):
+                        diff_geom = QgsGeometry(diff_geom.difference(tmpGeom))
                 except:
                     GEOS_EXCEPT = False
                     add = False
                     break
+
             if add:
                 try:
-                    outFeat.setGeometry( diff_geom )
-                    outFeat.setAttributes( atMap )
-                    writer.addFeature( outFeat )
+                    outFeat.setGeometry(diff_geom)
+                    outFeat.setAttributes(attrs)
+                    writer.addFeature(outFeat)
                 except:
                     FEATURE_EXCEPT = False
                     continue
 
+            current += 1
+            progress.setPercentage(int(current * total))
 
         del writer
+
         if not GEOS_EXCEPT:
             SextanteLog.addToLog(SextanteLog.LOG_WARNING, "Geometry exception while computing difference")
         if not FEATURE_EXCEPT:
             SextanteLog.addToLog(SextanteLog.LOG_WARNING, "Feature exception while computing difference")
-
-    def defineCharacteristics(self):
-        self.name = "Difference"
-        self.group = "Vector overlay tools"
-        self.addParameter(ParameterVector(Difference.INPUT, "Input layer", ParameterVector.VECTOR_TYPE_ANY))
-        self.addParameter(ParameterVector(Difference.INPUT2, "Difference layer", ParameterVector.VECTOR_TYPE_ANY))
-        self.addOutput(OutputVector(Difference.OUTPUT, "Difference"))