Add option to ignore interior polygon rings when calculating buffered shading for shapeburst fill mode (can be useful for eg ignoring islands when shading water bodies)

Author: nyalldawson

python/core/symbology-ng/qgsfillsymbollayerv2.sip

@@ -351,6 +351,20 @@ class QgsShapeburstFillSymbolLayerV2 : QgsFillSymbolLayerV2
      * @see colorType
     */
     QColor color2() const;
+    
+    /**Sets whether the shapeburst fill should ignore polygon rings when calculating
+     * the buffered shading.
+     * @param ignoreRings Set to true if buffers should ignore interior rings for polygons.
+     * @note added in 2.3
+     * @see ignoreRings
+    */
+    void setIgnoreRings( double ignoreRings );
+    /**Returns whether the shapeburst fill is set to ignore polygon interior rings.
+     * @returns True if the shapeburst fill will ignore interior rings when calculating buffered shading.
+     * @note added in 2.3
+     * @see setIgnoreRings
+    */
+    double ignoreRings() const;    
 
     /**Sets the offset for the shapeburst fill.
      * @param offset QPointF indicating the horizontal/vertical offset amount

src/core/symbology-ng/qgsfillsymbollayerv2.cpp

@@ -795,6 +795,7 @@ QgsShapeburstFillSymbolLayerV2::QgsShapeburstFillSymbolLayerV2( QColor color, QC
     mColor2( color2 ),
     mGradientRamp( NULL ),
     mTwoColorGradientRamp( 0 ),
+    mIgnoreRings( false ),
     mOffsetUnit( QgsSymbolV2::MM )
 {
   mColor = color;
@@ -859,6 +860,10 @@ QgsSymbolLayerV2* QgsShapeburstFillSymbolLayerV2::create( const QgsStringMap& pr
   {
     sl->setDistanceUnit( QgsSymbolLayerV2Utils::decodeOutputUnit( props["distance_unit"] ) );
   }
+  if ( props.contains( "ignore_rings" ) )
+  {
+    sl->setIgnoreRings( props["ignore_rings"].toInt() );
+  }
   if ( gradientRamp )
   {
     sl->setColorRamp( gradientRamp );
@@ -874,6 +879,8 @@ QgsSymbolLayerV2* QgsShapeburstFillSymbolLayerV2::create( const QgsStringMap& pr
     sl->setDataDefinedProperty( "use_whole_shape", props["use_whole_shape_expression"] );
   if ( props.contains( "max_distance_expression" ) )
     sl->setDataDefinedProperty( "max_distance", props["max_distance_expression"] );
+  if ( props.contains( "ignore_rings_expression" ) )
+    sl->setDataDefinedProperty( "ignore_rings", props["ignore_rings_expression"] );
 
   return sl;
 }
@@ -890,7 +897,7 @@ void QgsShapeburstFillSymbolLayerV2::setColorRamp( QgsVectorColorRampV2* ramp )
 }
 
 void QgsShapeburstFillSymbolLayerV2::applyDataDefinedSymbology( QgsSymbolV2RenderContext& context, QColor& color, QColor& color2, int& blurRadius, bool& useWholeShape,
-    double& maxDistance )
+    double& maxDistance, bool& ignoreRings )
 {
   //first gradient color
   QgsExpression* colorExpression = expression( "color" );
@@ -922,6 +929,12 @@ void QgsShapeburstFillSymbolLayerV2::applyDataDefinedSymbology( QgsSymbolV2Rende
   if ( maxDistanceExpression )
     maxDistance = maxDistanceExpression->evaluate( const_cast<QgsFeature*>( context.feature() ) ).toDouble();
 
+  //ignore rings
+  QgsExpression* ignoreRingsExpression = expression( "ignore_rings" );
+  ignoreRings = mIgnoreRings;
+  if ( ignoreRingsExpression )
+    ignoreRings = ignoreRingsExpression->evaluate( const_cast<QgsFeature*>( context.feature() ) ).toBool();
+
 }
 
 void QgsShapeburstFillSymbolLayerV2::startRender( QgsSymbolV2RenderContext& context )
@@ -970,8 +983,9 @@ void QgsShapeburstFillSymbolLayerV2::renderPolygon( const QPolygonF& points, QLi
   int blurRadius;
   bool useWholeShape;
   double maxDistance;
+  bool ignoreRings;
   //calculate data defined symbology
-  applyDataDefinedSymbology( context, color1, color2, blurRadius, useWholeShape, maxDistance );
+  applyDataDefinedSymbology( context, color1, color2, blurRadius, useWholeShape, maxDistance, ignoreRings );
 
   //calculate max distance for shapeburst fill to extend from polygon boundary, in pixels
   int outputPixelMaxDist = 0;
@@ -1022,7 +1036,21 @@ void QgsShapeburstFillSymbolLayerV2::renderPolygon( const QPolygonF& points, QLi
   //now that we have a render of the polygon in white, draw this onto the shapeburst fill image too
   //(this avoids calling _renderPolygon twice, since that can be slow)
   imgPainter.begin( fillImage );
-  imgPainter.drawImage( 0, 0, *alphaImage );
+  if ( !ignoreRings )
+  {
+    imgPainter.drawImage( 0, 0, *alphaImage );
+  }
+  else
+  {
+    //using ignore rings mode, so the alpha image can't be used
+    //directly as the alpha channel contains polygon rings and we need
+    //to draw now without any rings
+    imgPainter.setBrush( QBrush( Qt::white ) );
+    imgPainter.setPen( QPen( Qt::black ) );
+    imgPainter.translate( -points.boundingRect().left() + sideBuffer, - points.boundingRect().top() + sideBuffer );
+    imgPainter.scale( context.renderContext().rasterScaleFactor(), context.renderContext().rasterScaleFactor() );
+    _renderPolygon( &imgPainter, points, NULL, context );
+  }
   imgPainter.end();
 
   //apply distance transform to image, uses the current color ramp to calculate final pixel colours
@@ -1252,6 +1280,7 @@ QgsStringMap QgsShapeburstFillSymbolLayerV2::properties() const
   map["use_whole_shape"] = QString::number( mUseWholeShape );
   map["max_distance"] = QString::number( mMaxDistance );
   map["distance_unit"] = QgsSymbolLayerV2Utils::encodeOutputUnit( mDistanceUnit );
+  map["ignore_rings"] = QString::number( mIgnoreRings );
   map["offset"] = QgsSymbolLayerV2Utils::encodePoint( mOffset );
   map["offset_unit"] = QgsSymbolLayerV2Utils::encodeOutputUnit( mOffsetUnit );
 
@@ -1273,6 +1302,7 @@ QgsSymbolLayerV2* QgsShapeburstFillSymbolLayerV2::clone() const
     sl->setColorRamp( mGradientRamp->clone() );
   }
   sl->setDistanceUnit( mDistanceUnit );
+  sl->setIgnoreRings( mIgnoreRings );
   sl->setOffset( mOffset );
   sl->setOffsetUnit( mOffsetUnit );
   copyDataDefinedProperties( sl );

src/core/symbology-ng/qgsfillsymbollayerv2.h

@@ -421,6 +421,20 @@ class CORE_EXPORT QgsShapeburstFillSymbolLayerV2 : public QgsFillSymbolLayerV2
     */
     QColor color2() const { return mColor2; };
 
+    /**Sets whether the shapeburst fill should ignore polygon rings when calculating
+     * the buffered shading.
+     * @param ignoreRings Set to true if buffers should ignore interior rings for polygons.
+     * @note added in 2.3
+     * @see ignoreRings
+    */
+    void setIgnoreRings( double ignoreRings ) { mIgnoreRings = ignoreRings; };
+    /**Returns whether the shapeburst fill is set to ignore polygon interior rings.
+     * @returns True if the shapeburst fill will ignore interior rings when calculating buffered shading.
+     * @note added in 2.3
+     * @see setIgnoreRings
+    */
+    double ignoreRings() const { return mIgnoreRings; };
+
     /**Sets the offset for the shapeburst fill.
      * @param offset QPointF indicating the horizontal/vertical offset amount
      * @note added in 2.3
@@ -466,14 +480,16 @@ class CORE_EXPORT QgsShapeburstFillSymbolLayerV2 : public QgsFillSymbolLayerV2
     QgsVectorColorRampV2* mGradientRamp;
     QgsVectorColorRampV2* mTwoColorGradientRamp;
 
+    bool mIgnoreRings;
+
     QPointF mOffset;
     QgsSymbolV2::OutputUnit mOffsetUnit;
 
   private:
 
     //helper functions for data defined symbology
     void applyDataDefinedSymbology( QgsSymbolV2RenderContext& context, QColor& color, QColor& color2, int& blurRadius, bool& useWholeShape,
-                                    double& maxDistance );
+                                    double& maxDistance , bool &ignoreRings );
 
     /* distance transform of a 1d function using squared distance */
     void distanceTransform1d( double *f, int n, int *v, double *z, double *d );

src/gui/symbology-ng/qgssymbollayerv2widget.cpp

@@ -1090,6 +1090,10 @@ void QgsShapeburstFillSymbolLayerV2Widget::setSymbolLayer( QgsSymbolLayerV2* lay
   mDistanceUnitComboBox->setCurrentIndex( mLayer->distanceUnit() );
   mDistanceUnitComboBox->blockSignals( false );
 
+  mIgnoreRingsCheckBox->blockSignals( true );
+  mIgnoreRingsCheckBox->setCheckState( mLayer->ignoreRings() ? Qt::Checked : Qt::Unchecked );
+  mIgnoreRingsCheckBox->blockSignals( false );
+
   // set source color ramp
   if ( mLayer->colorRamp() )
   {
@@ -1228,6 +1232,7 @@ void QgsShapeburstFillSymbolLayerV2Widget::on_mDataDefinedPropertiesButton_click
       tr( "Integer between 0 and 18" ) );
   dataDefinedProperties << QgsDataDefinedSymbolDialog::DataDefinedSymbolEntry( "use_whole_shape", tr( "Use whole shape" ), mLayer->dataDefinedPropertyString( "use_whole_shape" ), QgsDataDefinedSymbolDialog::boolHelpText() );
   dataDefinedProperties << QgsDataDefinedSymbolDialog::DataDefinedSymbolEntry( "max_distance", tr( "Maximum distance" ), mLayer->dataDefinedPropertyString( "max_distance" ), QgsDataDefinedSymbolDialog::doubleHelpText() );
+  dataDefinedProperties << QgsDataDefinedSymbolDialog::DataDefinedSymbolEntry( "ignore_rings", tr( "Ignore rings" ), mLayer->dataDefinedPropertyString( "ignore_rings" ), QgsDataDefinedSymbolDialog::boolHelpText() );
 
   QgsDataDefinedSymbolDialog d( dataDefinedProperties, mVectorLayer );
   if ( d.exec() == QDialog::Accepted )
@@ -1248,6 +1253,13 @@ void QgsShapeburstFillSymbolLayerV2Widget::on_mDataDefinedPropertiesButton_click
   }
 }
 
+void QgsShapeburstFillSymbolLayerV2Widget::on_mIgnoreRingsCheckBox_stateChanged( int state )
+{
+  bool checked = ( state == Qt::Checked );
+  mLayer->setIgnoreRings( checked );
+  emit changed();
+}
+
 ///////////
 
 QgsMarkerLineSymbolLayerV2Widget::QgsMarkerLineSymbolLayerV2Widget( const QgsVectorLayer* vl, QWidget* parent )

src/gui/symbology-ng/qgssymbollayerv2widget.h

@@ -226,6 +226,7 @@ class GUI_EXPORT QgsShapeburstFillSymbolLayerV2Widget : public QgsSymbolLayerV2W
     void offsetChanged();
     void on_mOffsetUnitComboBox_currentIndexChanged( int index );
     void on_mDataDefinedPropertiesButton_clicked();
+    void on_mIgnoreRingsCheckBox_stateChanged( int state );
 
   protected:
     QgsShapeburstFillSymbolLayerV2* mLayer;

src/ui/symbollayer/widget_shapeburstfill.ui

@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>497</width>
-    <height>358</height>
+    <height>365</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -105,6 +105,13 @@
         </property>
        </widget>
       </item>
+      <item row="2" column="0">
+       <widget class="QCheckBox" name="mIgnoreRingsCheckBox">
+        <property name="text">
+         <string>Ignore rings in polygons while shading</string>
+        </property>
+       </widget>
+      </item>
       <item row="1" column="0" colspan="2">
        <layout class="QHBoxLayout" name="horizontalLayout_3">
         <property name="spacing">
@@ -152,14 +159,14 @@
      </layout>
     </widget>
    </item>
-   <item row="2" column="0">
+   <item row="4" column="0">
     <widget class="QLabel" name="label">
      <property name="text">
       <string>Blur strength</string>
      </property>
     </widget>
    </item>
-   <item row="2" column="1">
+   <item row="4" column="1">
     <layout class="QHBoxLayout" name="horizontalLayout_4">
      <item>
       <widget class="QSlider" name="mBlurSlider">
@@ -195,14 +202,14 @@
      </item>
     </layout>
    </item>
-   <item row="3" column="0">
+   <item row="5" column="0">
     <widget class="QLabel" name="label_6">
      <property name="text">
       <string>Offset X,Y</string>
      </property>
     </widget>
    </item>
-   <item row="3" column="1">
+   <item row="5" column="1">
     <layout class="QHBoxLayout" name="horizontalLayout">
      <item>
       <widget class="QDoubleSpinBox" name="spinOffsetX">
@@ -264,7 +271,7 @@
      </item>
     </layout>
    </item>
-   <item row="4" column="0" colspan="2">
+   <item row="6" column="0" colspan="2">
     <widget class="QPushButton" name="mDataDefinedPropertiesButton">
      <property name="sizePolicy">
       <sizepolicy hsizetype="Minimum" vsizetype="Fixed">

tests/src/core/testqgsshapeburst.cpp

@@ -55,6 +55,7 @@ class TestQgsShapeburst: public QObject
     void shapeburstBlur();
     void shapeburstMaxDistanceMm();
     void shapeburstMaxDistanceMapUnits();
+    void shapeburstIgnoreRings();
     void shapeburstSymbolFromQml();
 
   private:
@@ -179,7 +180,7 @@ void TestQgsShapeburst::shapeburstMaxDistanceMm()
   mShapeburstFill->setMaxDistance( 3 );
   mShapeburstFill->setDistanceUnit( QgsSymbolV2::MM );
   QVERIFY( imageCheck( "shapeburst_maxdistance_mm" ) );
-  mShapeburstFill->setUseWholeShape( true);
+  mShapeburstFill->setUseWholeShape( true );
 }
 
 void TestQgsShapeburst::shapeburstMaxDistanceMapUnits()
@@ -189,10 +190,18 @@ void TestQgsShapeburst::shapeburstMaxDistanceMapUnits()
   mShapeburstFill->setMaxDistance( 10 );
   mShapeburstFill->setDistanceUnit( QgsSymbolV2::MapUnit );
   QVERIFY( imageCheck( "shapeburst_maxdistance_mapunit" ) );
-  mShapeburstFill->setUseWholeShape( true);
+  mShapeburstFill->setUseWholeShape( true );
   mShapeburstFill->setDistanceUnit( QgsSymbolV2::MM );
 }
 
+void TestQgsShapeburst::shapeburstIgnoreRings()
+{
+  mReport += "<h2>Shapeburst symbol renderer ignore rings</h2>\n";
+  mShapeburstFill->setIgnoreRings( true );
+  QVERIFY( imageCheck( "shapeburst_ignorerings" ) );
+  mShapeburstFill->setIgnoreRings( false );
+}
+
 void TestQgsShapeburst::shapeburstSymbolFromQml()
 {
   mReport += "<h2>Shapeburst symbol from QML test</h2>\n";