[pal] Never treat features as obstacles for their own labels

Fixes issues like rule based labelling registering two labels for
a single feature which was resulting in each label colliding
with the feature's geometry registered by the other label. This
resulted in poor placement for these labels.

Sponsored by City of Uster

Author: nyalldawson

src/core/pal/feature.cpp

@@ -154,6 +154,14 @@ namespace pal
     return mLF->id();
   }
 
+  bool FeaturePart::hasSameLabelFeatureAs( FeaturePart* part ) const
+  {
+    if ( !part )
+      return false;
+
+    return mLF->id() == part->featureId() && mLF->layer()->name() == part->layer()->name();
+  }
+
   LabelPosition::Quadrant FeaturePart::quadrantFromOffset() const
   {
     QPointF quadOffset = mLF->quadOffset();

src/core/pal/feature.h

@@ -165,6 +165,12 @@ namespace pal
        */
       QgsFeatureId featureId() const;
 
+      /** Tests whether this feature part belongs to the same QgsLabelFeature as another
+       * feature part.
+       * @param part part to compare to
+       * @returns true if both parts belong to same QgsLabelFeature
+       */
+      bool hasSameLabelFeatureAs( FeaturePart* part ) const;
 
 #if 0
       /**

src/core/pal/labelposition.cpp

@@ -441,16 +441,22 @@ namespace pal
 
   //////////
 
-  bool LabelPosition::pruneCallback( LabelPosition *lp, void *ctx )
+  bool LabelPosition::pruneCallback( LabelPosition *candidatePosition, void *ctx )
   {
-    FeaturePart *feat = (( PruneCtx* ) ctx )->obstacle;
+    FeaturePart *obstaclePart = (( PruneCtx* ) ctx )->obstacle;
 
-    if (( feat == lp->feature ) || ( feat->getHoleOf() && feat->getHoleOf() != lp->feature ) )
+    // test whether we should ignore this obstacle for the candidate. We do this if:
+    // 1. it's not a hole, and the obstacle belongs to the same label feature as the candidate (eg
+    // features aren't obstacles for their own labels)
+    // 2. it IS a hole, and the hole belongs to a different label feature to the candidate (eg, holes
+    // are ONLY obstacles for the labels of the feature they belong to)
+    if (( !obstaclePart->getHoleOf() && candidatePosition->feature->hasSameLabelFeatureAs( obstaclePart ) )
+        || ( obstaclePart->getHoleOf() && !candidatePosition->feature->hasSameLabelFeatureAs( dynamic_cast< FeaturePart* >( obstaclePart->getHoleOf() ) ) ) )
     {
       return true;
     }
 
-    CostCalculator::addObstacleCostPenalty( lp, feat );
+    CostCalculator::addObstacleCostPenalty( candidatePosition, obstaclePart );
 
     return true;
   }

tests/src/python/test_qgspallabeling_placement.py

@@ -142,6 +142,40 @@ def test_point_placement_around_obstacle_large_symbol(self):
         self.removeMapLayer(self.layer)
         self.layer = None
 
+    def test_polygon_placement_with_hole(self):
+        # Horizontal label placement for polygon with hole
+        # Note for this test, the mask is used to check only pixels outside of the polygon.
+        # We don't care where in the polygon the label is, just that it
+        # is INSIDE the polygon
+        self.layer = TestQgsPalLabeling.loadFeatureLayer('polygon_with_hole')
+        self._TestMapSettings = self.cloneMapSettings(self._MapSettings)
+        self.lyr.placement = QgsPalLayerSettings.Horizontal
+        self.checkTest()
+        self.removeMapLayer(self.layer)
+        self.layer = None
+
+    def test_polygon_placement_with_hole_and_point(self):
+        # Testing that hole from a feature is not treated as an obstacle for other feature's labels
+        self.layer = TestQgsPalLabeling.loadFeatureLayer('point')
+        polyLayer = TestQgsPalLabeling.loadFeatureLayer('polygon_with_hole')
+        self._TestMapSettings = self.cloneMapSettings(self._MapSettings)
+        self.checkTest()
+        self.removeMapLayer(self.layer)
+        self.removeMapLayer(polyLayer)
+        self.layer = None
+
+    def test_polygon_multiple_labels(self):
+        # Horizontal label placement for polygon with hole
+        # Note for this test, the mask is used to check only pixels outside of the polygon.
+        # We don't care where in the polygon the label is, just that it
+        # is INSIDE the polygon
+        self.layer = TestQgsPalLabeling.loadFeatureLayer('polygon_rule_based')
+        self._TestMapSettings = self.cloneMapSettings(self._MapSettings)
+        self.lyr.placement = QgsPalLayerSettings.Horizontal
+        self.checkTest()
+        self.removeMapLayer(self.layer)
+        self.layer = None
+
 if __name__ == '__main__':
     # NOTE: unless PAL_SUITE env var is set all test class methods will be run
     # SEE: test_qgspallabeling_tests.suiteTests() to define suite

tests/testdata/control_images/expected_pal_placement/sp_polygon_multiple_labels/sp_polygon_multiple_labels.png

@@ -0,0 +1,128 @@
+<!DOCTYPE qgis PUBLIC 'http://mrcc.com/qgis.dtd' 'SYSTEM'>
+<qgis version="2.13.0-Master" minimumScale="0" maximumScale="1e+08" simplifyDrawingHints="1" minLabelScale="0" maxLabelScale="1e+08" simplifyDrawingTol="1" simplifyMaxScale="1" hasScaleBasedVisibilityFlag="0" simplifyLocal="1" scaleBasedLabelVisibilityFlag="0">
+  <edittypes>
+    <edittype widgetv2type="TextEdit" name="pkuid">
+      <widgetv2config IsMultiline="0" fieldEditable="1" UseHtml="0" labelOnTop="0"/>
+    </edittype>
+    <edittype widgetv2type="TextEdit" name="ftype">
+      <widgetv2config IsMultiline="0" fieldEditable="1" UseHtml="0" labelOnTop="0"/>
+    </edittype>
+    <edittype widgetv2type="TextEdit" name="text">
+      <widgetv2config IsMultiline="0" fieldEditable="1" UseHtml="0" labelOnTop="0"/>
+    </edittype>
+  </edittypes>
+  <renderer-v2 forceraster="0" symbollevels="0" type="singleSymbol">
+    <symbols>
+      <symbol alpha="1" clip_to_extent="1" type="fill" name="0">
+        <layer pass="0" class="SimpleFill" locked="0">
+          <prop k="border_width_map_unit_scale" v="0,0,0,0,0,0"/>
+          <prop k="color" v="133,149,161,255"/>
+          <prop k="joinstyle" v="bevel"/>
+          <prop k="offset" v="0,0"/>
+          <prop k="offset_map_unit_scale" v="0,0,0,0,0,0"/>
+          <prop k="offset_unit" v="MM"/>
+          <prop k="outline_color" v="0,0,0,255"/>
+          <prop k="outline_style" v="no"/>
+          <prop k="outline_width" v="0.26"/>
+          <prop k="outline_width_unit" v="MM"/>
+          <prop k="style" v="solid"/>
+        </layer>
+      </symbol>
+    </symbols>
+    <rotation/>
+    <sizescale scalemethod="diameter"/>
+  </renderer-v2>
+  <labeling type="rule-based">
+    <rules>
+      <rule>
+        <settings>
+          <text-style fontItalic="1" fontFamily="Ubuntu" fontLetterSpacing="0" fontUnderline="0" fontSizeMapUnitMaxScale="0" fontWeight="63" fontStrikeout="0" textTransp="0" previewBkgrdColor="#ffffff" fontCapitals="0" textColor="0,0,0,255" fontSizeMapUnitMinScale="0" fontSizeInMapUnits="0" isExpression="0" blendMode="0" fontSize="11" fieldName="text" namedStyle="Medium Italic" fontWordSpacing="0"/>
+          <text-format placeDirectionSymbol="0" multilineAlign="0" rightDirectionSymbol=">" multilineHeight="1" plussign="0" addDirectionSymbol="0" leftDirectionSymbol="&lt;" formatNumbers="0" decimals="3" wrapChar="" reverseDirectionSymbol="0"/>
+          <text-buffer bufferSize="1" bufferSizeMapUnitMinScale="0" bufferColor="255,255,255,255" bufferDraw="0" bufferBlendMode="0" bufferTransp="0" bufferSizeInMapUnits="0" bufferSizeMapUnitMaxScale="0" bufferNoFill="0" bufferJoinStyle="64"/>
+          <background shapeSizeUnits="1" shapeType="0" shapeOffsetMapUnitMinScale="0" shapeSizeMapUnitMinScale="0" shapeSVGFile="" shapeOffsetX="0" shapeOffsetY="0" shapeBlendMode="0" shapeBorderWidthMapUnitMaxScale="0" shapeFillColor="255,255,255,255" shapeTransparency="0" shapeSizeType="0" shapeJoinStyle="64" shapeDraw="0" shapeSizeMapUnitMaxScale="0" shapeBorderWidthUnits="1" shapeSizeX="0" shapeSizeY="0" shapeRadiiX="0" shapeOffsetMapUnitMaxScale="0" shapeOffsetUnits="1" shapeRadiiY="0" shapeRotation="0" shapeBorderWidth="0" shapeRadiiMapUnitMinScale="0" shapeRadiiMapUnitMaxScale="0" shapeBorderColor="128,128,128,255" shapeRotationType="0" shapeRadiiUnits="1" shapeBorderWidthMapUnitMinScale="0"/>
+          <shadow shadowOffsetGlobal="1" shadowRadiusUnits="1" shadowRadiusMapUnitMinScale="0" shadowTransparency="30" shadowColor="0,0,0,255" shadowUnder="0" shadowScale="100" shadowOffsetDist="1" shadowOffsetMapUnitMinScale="0" shadowRadiusMapUnitMaxScale="0" shadowDraw="0" shadowOffsetAngle="135" shadowRadius="1.5" shadowBlendMode="6" shadowOffsetMapUnitMaxScale="0" shadowRadiusAlphaOnly="0" shadowOffsetUnits="1"/>
+          <placement repeatDistanceUnit="1" placement="1" maxCurvedCharAngleIn="20" repeatDistance="0" distMapUnitMaxScale="0" labelOffsetMapUnitMaxScale="0" distInMapUnits="0" labelOffsetInMapUnits="0" xOffset="0" preserveRotation="1" centroidWhole="0" priority="5" repeatDistanceMapUnitMaxScale="0" yOffset="-2" placementFlags="10" repeatDistanceMapUnitMinScale="0" centroidInside="0" dist="0" angleOffset="0" maxCurvedCharAngleOut="-20" fitInPolygonOnly="0" quadOffset="1" distMapUnitMinScale="0" labelOffsetMapUnitMinScale="0"/>
+          <rendering fontMinPixelSize="3" scaleMax="10000000" fontMaxPixelSize="10000" scaleMin="1" upsidedownLabels="0" limitNumLabels="0" obstacle="1" obstacleFactor="1" scaleVisibility="0" fontLimitPixelSize="0" mergeLines="0" obstacleType="0" labelPerPart="0" maxNumLabels="2000" displayAll="0" minFeatureSize="0"/>
+          <data-defined/>
+        </settings>
+      </rule>
+      <rule>
+        <settings>
+          <text-style fontItalic="1" fontFamily="Ubuntu" fontLetterSpacing="0" fontUnderline="0" fontSizeMapUnitMaxScale="0" fontWeight="63" fontStrikeout="0" textTransp="0" previewBkgrdColor="#ffffff" fontCapitals="0" textColor="0,0,0,255" fontSizeMapUnitMinScale="0" fontSizeInMapUnits="0" isExpression="0" blendMode="0" fontSize="11" fieldName="text" namedStyle="Medium Italic" fontWordSpacing="0"/>
+          <text-format placeDirectionSymbol="0" multilineAlign="0" rightDirectionSymbol=">" multilineHeight="1" plussign="0" addDirectionSymbol="0" leftDirectionSymbol="&lt;" formatNumbers="0" decimals="3" wrapChar="" reverseDirectionSymbol="0"/>
+          <text-buffer bufferSize="1" bufferSizeMapUnitMinScale="0" bufferColor="255,255,255,255" bufferDraw="0" bufferBlendMode="0" bufferTransp="0" bufferSizeInMapUnits="0" bufferSizeMapUnitMaxScale="0" bufferNoFill="0" bufferJoinStyle="64"/>
+          <background shapeSizeUnits="1" shapeType="0" shapeOffsetMapUnitMinScale="0" shapeSizeMapUnitMinScale="0" shapeSVGFile="" shapeOffsetX="0" shapeOffsetY="0" shapeBlendMode="0" shapeBorderWidthMapUnitMaxScale="0" shapeFillColor="255,255,255,255" shapeTransparency="0" shapeSizeType="0" shapeJoinStyle="64" shapeDraw="0" shapeSizeMapUnitMaxScale="0" shapeBorderWidthUnits="1" shapeSizeX="0" shapeSizeY="0" shapeRadiiX="0" shapeOffsetMapUnitMaxScale="0" shapeOffsetUnits="1" shapeRadiiY="0" shapeRotation="0" shapeBorderWidth="0" shapeRadiiMapUnitMinScale="0" shapeRadiiMapUnitMaxScale="0" shapeBorderColor="128,128,128,255" shapeRotationType="0" shapeRadiiUnits="1" shapeBorderWidthMapUnitMinScale="0"/>
+          <shadow shadowOffsetGlobal="1" shadowRadiusUnits="1" shadowRadiusMapUnitMinScale="0" shadowTransparency="30" shadowColor="0,0,0,255" shadowUnder="0" shadowScale="100" shadowOffsetDist="1" shadowOffsetMapUnitMinScale="0" shadowRadiusMapUnitMaxScale="0" shadowDraw="0" shadowOffsetAngle="135" shadowRadius="1.5" shadowBlendMode="6" shadowOffsetMapUnitMaxScale="0" shadowRadiusAlphaOnly="0" shadowOffsetUnits="1"/>
+          <placement repeatDistanceUnit="1" placement="1" maxCurvedCharAngleIn="20" repeatDistance="0" distMapUnitMaxScale="0" labelOffsetMapUnitMaxScale="0" distInMapUnits="0" labelOffsetInMapUnits="0" xOffset="0" preserveRotation="1" centroidWhole="0" priority="5" repeatDistanceMapUnitMaxScale="0" yOffset="2" placementFlags="10" repeatDistanceMapUnitMinScale="0" centroidInside="0" dist="0" angleOffset="0" maxCurvedCharAngleOut="-20" fitInPolygonOnly="0" quadOffset="7" distMapUnitMinScale="0" labelOffsetMapUnitMinScale="0"/>
+          <rendering fontMinPixelSize="3" scaleMax="10000000" fontMaxPixelSize="10000" scaleMin="1" upsidedownLabels="0" limitNumLabels="0" obstacle="1" obstacleFactor="1" scaleVisibility="0" fontLimitPixelSize="0" mergeLines="0" obstacleType="0" labelPerPart="0" maxNumLabels="2000" displayAll="0" minFeatureSize="0"/>
+          <data-defined/>
+        </settings>
+      </rule>
+    </rules>
+  </labeling>
+  <customproperties>
+    <property key="variableNames" value="_fields_"/>
+    <property key="variableValues" value=""/>
+  </customproperties>
+  <blendMode>0</blendMode>
+  <featureBlendMode>0</featureBlendMode>
+  <layerTransparency>0</layerTransparency>
+  <displayfield>pkuid</displayfield>
+  <label>0</label>
+  <labelattributes>
+    <label fieldname="" text="Label"/>
+    <family fieldname="" name="Ubuntu"/>
+    <size fieldname="" units="pt" value="12"/>
+    <bold fieldname="" on="0"/>
+    <italic fieldname="" on="0"/>
+    <underline fieldname="" on="0"/>
+    <strikeout fieldname="" on="0"/>
+    <color fieldname="" red="0" blue="0" green="0"/>
+    <x fieldname=""/>
+    <y fieldname=""/>
+    <offset x="0" y="0" units="pt" yfieldname="" xfieldname=""/>
+    <angle fieldname="" value="0" auto="0"/>
+    <alignment fieldname="" value="center"/>
+    <buffercolor fieldname="" red="255" blue="255" green="255"/>
+    <buffersize fieldname="" units="pt" value="1"/>
+    <bufferenabled fieldname="" on=""/>
+    <multilineenabled fieldname="" on=""/>
+    <selectedonly on=""/>
+  </labelattributes>
+  <SingleCategoryDiagramRenderer diagramType="Pie">
+    <DiagramCategory penColor="#000000" labelPlacementMethod="XHeight" penWidth="0" diagramOrientation="Up" minimumSize="0" barWidth="5" penAlpha="255" maxScaleDenominator="1e+08" backgroundColor="#ffffff" transparency="0" width="15" scaleDependency="Area" backgroundAlpha="255" angleOffset="1440" scaleBasedVisibility="0" enabled="0" height="15" sizeType="MM" minScaleDenominator="0">
+      <fontProperties description="Ubuntu,11,-1,5,50,0,0,0,0,0" style=""/>
+    </DiagramCategory>
+  </SingleCategoryDiagramRenderer>
+  <DiagramLayerSettings yPosColumn="-1" linePlacementFlags="10" placement="0" dist="0" xPosColumn="-1" priority="0" obstacle="0" showAll="1"/>
+  <editform></editform>
+  <editforminit/>
+  <editforminitusecode>0</editforminitusecode>
+  <editforminitcode><![CDATA[# -*- coding: utf-8 -*-
+"""
+QGIS forms can have a Python function that is called when the form is
+opened.
+
+Use this function to add extra logic to your forms.
+
+Enter the name of the function in the "Python Init function"
+field.
+An example follows:
+"""
+from PyQt4.QtGui import QWidget
+
+def my_form_open(dialog, layer, feature):
+	geom = feature.geometry()
+	control = dialog.findChild(QWidget, "MyLineEdit")
+]]></editforminitcode>
+  <featformsuppress>0</featformsuppress>
+  <annotationform></annotationform>
+  <editorlayout>generatedlayout</editorlayout>
+  <excludeAttributesWMS/>
+  <excludeAttributesWFS/>
+  <attributeactions/>
+  <conditionalstyles>
+    <rowstyles/>
+    <fieldstyles/>
+  </conditionalstyles>
+</qgis>