Add blending mode for overview frame, option to invert overview frame

Author: nyalldawson

python/core/composer/qgscomposermap.sip

@@ -278,6 +278,18 @@ class QgsComposerMap : QgsComposerItem
     void setOverviewFrameMapSymbol( QgsFillSymbolV2* symbol /Transfer/ );
     QgsFillSymbolV2* overviewFrameMapSymbol();
 
+     /* Returns the blending mode for the overview frame
+    @note added in version 1.9*/
+    const QPainter::CompositionMode overviewBlendMode() const;
+    /* Sets the blending mode for the overview frame 
+    @note added in version 1.9*/    
+    void setOverviewBlendMode( const QPainter::CompositionMode blendMode );
+    
+    /**Sets flag if overview frame should be inverted
+    @note this function was added in version 1.9*/
+    void setOverviewInverted( bool inverted );
+    bool overviewInverted() const;        
+
     /**Sets mId to a number not yet used in the composition. mId is kept if it is not in use.
         Usually, this function is called before adding the composer map to the composition*/
     void assignFreeId();

src/app/composer/qgscomposermapwidget.cpp

@@ -299,6 +299,10 @@ void QgsComposerMapWidget::updateGuiElements()
     //overview frame
     int overviewMapFrameId = mComposerMap->overviewFrameMapId();
     mOverviewFrameMapComboBox->setCurrentIndex( mOverviewFrameMapComboBox->findData( overviewMapFrameId ) );
+    //overview frame blending mode
+    mOverviewBlendModeComboBox->setBlendMode( mComposerMap->overviewBlendMode() );
+    //overview inverted
+    mOverviewInvertCheckbox->setChecked( mComposerMap->overviewInverted() );
 
     //grid
     if ( mComposerMap->gridEnabled() )
@@ -437,6 +441,8 @@ void QgsComposerMapWidget::blockAllSignals( bool b )
   mFrameWidthSpinBox->blockSignals( b );
   mOverviewFrameMapComboBox->blockSignals( b );
   mOverviewFrameStyleButton->blockSignals( b );
+  mOverviewBlendModeComboBox->blockSignals( b );
+  mOverviewInvertCheckbox->blockSignals( b );
 }
 
 void QgsComposerMapWidget::on_mUpdatePreviewButton_clicked()
@@ -559,6 +565,23 @@ void QgsComposerMapWidget::on_mOverviewFrameStyleButton_clicked()
   }
 }
 
+void QgsComposerMapWidget::on_mOverviewBlendModeComboBox_currentIndexChanged( int index )
+{
+  Q_UNUSED( index );
+  if ( mComposerMap )
+  {
+    mComposerMap->setOverviewBlendMode( mOverviewBlendModeComboBox->blendMode() );
+  }
+
+}
+void QgsComposerMapWidget::on_mOverviewInvertCheckbox_toggled( bool state )
+{
+  if ( mComposerMap )
+  {
+    mComposerMap->setOverviewInverted( state );
+  }
+}
+
 void QgsComposerMapWidget::on_mGridCheckBox_toggled( bool state )
 {
   if ( !mComposerMap )

src/app/composer/qgscomposermapwidget.h

@@ -44,6 +44,8 @@ class QgsComposerMapWidget: public QWidget, private Ui::QgsComposerMapWidgetBase
     void on_mDrawCanvasItemsCheckBox_stateChanged( int state );
     void on_mOverviewFrameMapComboBox_currentIndexChanged( const QString& text );
     void on_mOverviewFrameStyleButton_clicked();
+    void on_mOverviewBlendModeComboBox_currentIndexChanged( int index );
+    void on_mOverviewInvertCheckbox_toggled( bool state );
 
     void on_mXMinLineEdit_editingFinished();
     void on_mXMaxLineEdit_editingFinished();

src/core/composer/qgscomposermap.cpp

@@ -40,7 +40,7 @@
 
 QgsComposerMap::QgsComposerMap( QgsComposition *composition, int x, int y, int width, int height )
     : QgsComposerItem( x, y, width, height, composition ), mKeepLayerSet( false ),
-    mOverviewFrameMapId( -1 ), mGridEnabled( false ), mGridStyle( Solid ),
+    mOverviewFrameMapId( -1 ), mOverviewBlendMode( QPainter::CompositionMode_SourceOver ), mOverviewInverted( false ), mGridEnabled( false ), mGridStyle( Solid ),
     mGridIntervalX( 0.0 ), mGridIntervalY( 0.0 ), mGridOffsetX( 0.0 ), mGridOffsetY( 0.0 ), mGridAnnotationPrecision( 3 ), mShowGridAnnotation( false ),
     mLeftGridAnnotationPosition( OutsideMapFrame ), mRightGridAnnotationPosition( OutsideMapFrame ), mTopGridAnnotationPosition( OutsideMapFrame ),
     mBottomGridAnnotationPosition( OutsideMapFrame ), mAnnotationFrameDistance( 1.0 ), mLeftGridAnnotationDirection( Horizontal ), mRightGridAnnotationDirection( Horizontal ),
@@ -82,7 +82,8 @@ QgsComposerMap::QgsComposerMap( QgsComposition *composition, int x, int y, int w
 }
 
 QgsComposerMap::QgsComposerMap( QgsComposition *composition )
-    : QgsComposerItem( 0, 0, 10, 10, composition ), mKeepLayerSet( false ), mOverviewFrameMapId( -1 ), mGridEnabled( false ), mGridStyle( Solid ),
+    : QgsComposerItem( 0, 0, 10, 10, composition ), mKeepLayerSet( false ), mOverviewFrameMapId( -1 ),
+    mOverviewBlendMode( QPainter::CompositionMode_SourceOver ), mOverviewInverted( false ), mGridEnabled( false ), mGridStyle( Solid ),
     mGridIntervalX( 0.0 ), mGridIntervalY( 0.0 ), mGridOffsetX( 0.0 ), mGridOffsetY( 0.0 ), mGridAnnotationPrecision( 3 ), mShowGridAnnotation( false ),
     mLeftGridAnnotationPosition( OutsideMapFrame ), mRightGridAnnotationPosition( OutsideMapFrame ), mTopGridAnnotationPosition( OutsideMapFrame ),
     mBottomGridAnnotationPosition( OutsideMapFrame ), mAnnotationFrameDistance( 1.0 ), mLeftGridAnnotationDirection( Horizontal ), mRightGridAnnotationDirection( Horizontal ),
@@ -283,7 +284,7 @@ void QgsComposerMap::paint( QPainter* painter, const QStyleOptionGraphicsItem* i
     //Qt 4.4.0 and 4.4.1 have problems with recursive paintings
     //QgsComposerMap::cache() and QgsComposerMap::update() need to be called by
     //client functions
-    
+
     //Background color is already included in cached image, so no need to draw
 
     QgsRectangle requestRectangle;
@@ -682,10 +683,20 @@ bool QgsComposerMap::writeXML( QDomElement& elem, QDomDocument & doc ) const
   //overview map frame
   QDomElement overviewFrameElem = doc.createElement( "overviewFrame" );
   overviewFrameElem.setAttribute( "overviewFrameMap", mOverviewFrameMapId );
+  overviewFrameElem.setAttribute( "overviewBlendMode", QgsMapRenderer::getBlendModeEnum( mOverviewBlendMode ) );
+  if ( mOverviewInverted )
+  {
+    overviewFrameElem.setAttribute( "overviewInverted", "true" );
+  }
+  else
+  {
+    overviewFrameElem.setAttribute( "overviewInverted", "false" );
+  }
   QDomElement overviewFrameStyleElem = QgsSymbolLayerV2Utils::saveSymbol( QString(), mOverviewFrameMapSymbol, doc );
   overviewFrameElem.appendChild( overviewFrameStyleElem );
   composerMapElem.appendChild( overviewFrameElem );
 
+
   //extent
   QDomElement extentElem = doc.createElement( "Extent" );
   extentElem.setAttribute( "xmin", QString::number( mExtent.xMinimum() ) );
@@ -779,6 +790,18 @@ bool QgsComposerMap::readXML( const QDomElement& itemElem, const QDomDocument& d
   if ( !overviewFrameElem.isNull() )
   {
     setOverviewFrameMap( overviewFrameElem.attribute( "overviewFrameMap", "-1" ).toInt() );
+    setOverviewBlendMode( QgsMapRenderer::getCompositionMode(( QgsMapRenderer::BlendMode ) overviewFrameElem.attribute( "overviewBlendMode", "0" ).toUInt() ) );
+
+    QString overviewInvertedFlag = overviewFrameElem.attribute( "overviewInverted" );
+    if ( overviewInvertedFlag.compare( "true", Qt::CaseInsensitive ) == 0 )
+    {
+      setOverviewInverted( true );
+    }
+    else
+    {
+      setOverviewInverted( false );
+    }
+
     QDomElement overviewFrameSymbolElem = overviewFrameElem.firstChildElement( "symbol" );
     if ( !overviewFrameSymbolElem.isNull() )
     {
@@ -1699,6 +1722,18 @@ void QgsComposerMap::setOverviewFrameMapSymbol( QgsFillSymbolV2* symbol )
   mOverviewFrameMapSymbol = symbol;
 }
 
+void QgsComposerMap::setOverviewBlendMode( QPainter::CompositionMode blendMode )
+{
+  mOverviewBlendMode = blendMode;
+  update();
+}
+
+void QgsComposerMap::setOverviewInverted( bool inverted )
+{
+  mOverviewInverted = inverted;
+  update();
+}
+
 void QgsComposerMap::setGridLineSymbol( QgsLineSymbolV2* symbol )
 {
   delete mGridLineSymbol;
@@ -2043,17 +2078,38 @@ void QgsComposerMap::drawOverviewMapExtent( QPainter* p )
     context.setRasterScaleFactor( mComposition->printResolution() / 25.4 );
   }
 
-  QPolygonF polygon;
+  p->save();
+  p->setCompositionMode( mOverviewBlendMode );
+  mOverviewFrameMapSymbol->startRender( context );
+
+  //construct a polygon corresponding to the intersecting map extent
+  QPolygonF intersectPolygon;
   double x = ( intersectRect.xMinimum() - thisExtent.xMinimum() ) / thisExtent.width() * rect().width();
   double y = ( thisExtent.yMaximum() - intersectRect.yMaximum() ) / thisExtent.height() * rect().height();
   double width = intersectRect.width() / thisExtent.width() * rect().width();
   double height = intersectRect.height() / thisExtent.height() * rect().height();
-  polygon << QPointF( x, y ) << QPointF( x + width, y ) << QPointF( x + width, y + height ) << QPointF( x, y + height ) << QPointF( x, y );
+  intersectPolygon << QPointF( x, y ) << QPointF( x + width, y ) << QPointF( x + width, y + height ) << QPointF( x, y + height ) << QPointF( x, y );
 
   QList<QPolygonF> rings; //empty list
-  mOverviewFrameMapSymbol->startRender( context );
-  mOverviewFrameMapSymbol->renderPolygon( polygon, &rings, 0, context );
+  if ( !mOverviewInverted )
+  {
+    //Render the intersecting map extent
+    mOverviewFrameMapSymbol->renderPolygon( intersectPolygon, &rings, 0, context );;
+  }
+  else
+  {
+    //We are inverting the overview frame (ie, shading outside the intersecting extent)
+    //Construct a polygon corresponding to the overview map extent
+    QPolygonF outerPolygon;
+    outerPolygon << QPointF( 0, 0 ) << QPointF( rect().width(), 0 ) << QPointF( rect().width(), rect().height() ) << QPointF( 0, rect().height() ) << QPointF( 0, 0 );
+
+    //Intersecting extent is an inner ring for the shaded area
+    rings.append( intersectPolygon );
+    mOverviewFrameMapSymbol->renderPolygon( outerPolygon, &rings, 0, context );
+  }
+
   mOverviewFrameMapSymbol->stopRender( context );
+  p->restore();
 }
 
 void QgsComposerMap::createDefaultOverviewFrameSymbol()

src/core/composer/qgscomposermap.h

@@ -312,6 +312,16 @@ class CORE_EXPORT QgsComposerMap : public QgsComposerItem
     void setOverviewFrameMapSymbol( QgsFillSymbolV2* symbol );
     QgsFillSymbolV2* overviewFrameMapSymbol() { return mOverviewFrameMapSymbol; }
 
+    /** Returns the overview's blending mode */
+    QPainter::CompositionMode overviewBlendMode() const {return mOverviewBlendMode;}
+    /** Sets the overview's blending mode*/
+    void setOverviewBlendMode( QPainter::CompositionMode blendMode );
+
+    /** Returns true if the overview frame is inverted */
+    bool overviewInverted() const {return mOverviewInverted;}
+    /** Sets the overview's inversion mode*/
+    void setOverviewInverted( bool inverted );
+
     void setGridLineSymbol( QgsLineSymbolV2* symbol );
     QgsLineSymbolV2* gridLineSymbol() { return mGridLineSymbol; }
 
@@ -380,6 +390,9 @@ class CORE_EXPORT QgsComposerMap : public QgsComposerItem
     /**Drawing style for overview farme*/
     QgsFillSymbolV2* mOverviewFrameMapSymbol;
     QgsLineSymbolV2* mGridLineSymbol;
+    /**Blend mode for overview*/
+    QPainter::CompositionMode mOverviewBlendMode;
+    bool mOverviewInverted;
 
     /**Establishes signal/slot connection for update in case of layer change*/
     void connectUpdateSlot();

src/ui/qgscomposermapwidgetbase.ui

@@ -663,6 +663,23 @@
             </property>
            </widget>
           </item>
+          <item row="2" column="0">
+           <widget class="QLabel" name="mOverviewBlendModeLabel">
+            <property name="text">
+             <string>Overview blending mode</string>
+            </property>
+           </widget>
+          </item>
+          <item row="2" column="1">
+           <widget class="QgsBlendModeComboBox" name="mOverviewBlendModeComboBox"/>
+          </item>
+          <item row="3" column="0">
+           <widget class="QCheckBox" name="mOverviewInvertCheckbox">
+            <property name="text">
+             <string>Invert overview</string>
+            </property>
+           </widget>
+          </item>
          </layout>
         </widget>
        </item>
@@ -680,6 +697,11 @@
    <header location="global">qgscollapsiblegroupbox.h</header>
    <container>1</container>
   </customwidget>
+  <customwidget>
+   <class>QgsBlendModeComboBox</class>
+   <extends>QComboBox</extends>
+   <header>qgsblendmodecombobox.h</header>
+  </customwidget>
  </customwidgets>
  <resources/>
  <connections/>

tests/src/core/testqgscomposermap.cpp

@@ -37,6 +37,8 @@ class TestQgsComposerMap: public QObject
     void render(); //test if rendering of the composition with composr map is correct
     void grid(); //test if grid and grid annotation works
     void overviewMap(); //test if overview map frame works
+    void overviewMapBlending(); //test if blend modes with overview map frame works
+    void overviewMapInvert(); //test if invert of overview map frame works
     void uniqueId(); //test if map id is adapted when doing copy paste
     void zebraStyle(); //test zebra map border style
 
@@ -135,6 +137,40 @@ void TestQgsComposerMap::overviewMap()
   QVERIFY( testResult );
 }
 
+void TestQgsComposerMap::overviewMapBlending()
+{
+  QgsComposerMap* overviewMapBlend = new QgsComposerMap( mComposition, 20, 130, 70, 70 );
+  overviewMapBlend->setFrameEnabled( true );
+  mComposition->addComposerMap( overviewMapBlend );
+  mComposerMap->setNewExtent( QgsRectangle( 785462.375, 3341423.125, 789262.375, 3343323.125 ) ); //zoom in
+  overviewMapBlend->setNewExtent( QgsRectangle( 781662.375, 3339523.125, 793062.375, 3350923.125 ) );
+  overviewMapBlend->setOverviewFrameMap( mComposerMap->id() );
+  overviewMapBlend->setOverviewBlendMode( QPainter::CompositionMode_Multiply );
+
+  QgsCompositionChecker checker( "Composer map overview blending", mComposition, QString( QString( TEST_DATA_DIR ) + QDir::separator() +
+                                 "control_images" + QDir::separator() + "expected_composermap" + QDir::separator() + "composermap_landsat_overview_blend.png" ) );
+  bool testResult = checker.testComposition();
+  mComposition->removeComposerItem( overviewMapBlend );
+  QVERIFY( testResult );
+}
+
+void TestQgsComposerMap::overviewMapInvert()
+{
+  QgsComposerMap* overviewMapInvert = new QgsComposerMap( mComposition, 20, 130, 70, 70 );
+  overviewMapInvert->setFrameEnabled( true );
+  mComposition->addComposerMap( overviewMapInvert );
+  mComposerMap->setNewExtent( QgsRectangle( 785462.375, 3341423.125, 789262.375, 3343323.125 ) ); //zoom in
+  overviewMapInvert->setNewExtent( QgsRectangle( 781662.375, 3339523.125, 793062.375, 3350923.125 ) );
+  overviewMapInvert->setOverviewFrameMap( mComposerMap->id() );
+  overviewMapInvert->setOverviewInverted( true );
+
+  QgsCompositionChecker checker( "Composer map overview invert", mComposition, QString( QString( TEST_DATA_DIR ) + QDir::separator() +
+                                 "control_images" + QDir::separator() + "expected_composermap" + QDir::separator() + "composermap_landsat_overview_invert.png" ) );
+  bool testResult = checker.testComposition();
+  mComposition->removeComposerItem( overviewMapInvert );
+  QVERIFY( testResult );
+}
+
 void TestQgsComposerMap::uniqueId()
 {
   QDomDocument doc;

tests/src/python/test_qgscomposermap.py

@@ -16,6 +16,7 @@
 from PyQt4.QtCore import (QStringList,
                           QFileInfo)
 from PyQt4.QtXml import QDomDocument
+from PyQt4.QtGui import QPainter
 
 from qgis.core import (QgsComposerMap,
                        QgsRectangle,
@@ -126,7 +127,56 @@ def testOverviewMap(self):
         self.mComposition.removeComposerItem(overviewMap)
         assert myTestResult == True, myMessage
 
-
+    def testOverviewMapBlend(self):
+        overviewMap = QgsComposerMap(self.mComposition, 20, 130, 70, 70)
+        overviewMap.setFrameEnabled(True)
+        self.mComposition.addComposerMap(overviewMap)
+        # zoom in
+        myRectangle = QgsRectangle(785462.375, 3341423.125,
+                                   789262.375, 3343323.125)
+        self.mComposerMap.setNewExtent(myRectangle)
+        myRectangle2 = QgsRectangle(781662.375, 3339523.125,
+                                    793062.375, 3350923.125)
+        overviewMap.setNewExtent(myRectangle2)
+        overviewMap.setOverviewFrameMap(self.mComposerMap.id())
+        overviewMap.setOverviewBlendMode(QPainter.CompositionMode_Multiply)
+        checker = QgsCompositionChecker()
+        myPngPath = os.path.join(TEST_DATA_DIR,
+                                 'control_images',
+                                 'expected_composermap',
+                                 'composermap_landsat_overview_blend.png')
+        myTestResult, myMessage = checker.testComposition(
+                                  'Composer map overview blending',
+                                  self.mComposition,
+                                  myPngPath)
+        self.mComposition.removeComposerItem(overviewMap)
+        assert myTestResult == True, myMessage
+        
+    def testOverviewMapInvert(self):
+        overviewMap = QgsComposerMap(self.mComposition, 20, 130, 70, 70)
+        overviewMap.setFrameEnabled(True)
+        self.mComposition.addComposerMap(overviewMap)
+        # zoom in
+        myRectangle = QgsRectangle(785462.375, 3341423.125,
+                                   789262.375, 3343323.125)
+        self.mComposerMap.setNewExtent(myRectangle)
+        myRectangle2 = QgsRectangle(781662.375, 3339523.125,
+                                    793062.375, 3350923.125)
+        overviewMap.setNewExtent(myRectangle2)
+        overviewMap.setOverviewFrameMap(self.mComposerMap.id())
+        overviewMap.setOverviewInverted(True)
+        checker = QgsCompositionChecker()
+        myPngPath = os.path.join(TEST_DATA_DIR,
+                                 'control_images',
+                                 'expected_composermap',
+                                 'composermap_landsat_overview_invert.png')
+        myTestResult, myMessage = checker.testComposition(
+                                  'Composer map overview inverted',
+                                  self.mComposition,
+                                  myPngPath)
+        self.mComposition.removeComposerItem(overviewMap)
+        assert myTestResult == True, myMessage
+        
     # Fails because addItemsFromXML has been commented out in sip
     @expectedFailure
     def testuniqueId(self):