Draw background on painter before rendering map for composer map items (fix #7461)

nyalldawson · nyalldawson · commit e6f3b2e0086b · 2013-04-17T14:58:53.000+10:00
diff --git a/src/app/composer/qgscomposeritemwidget.cpp b/src/app/composer/qgscomposeritemwidget.cpp
@@ -102,7 +102,8 @@ void QgsComposerItemWidget::on_mBackgroundColorButton_colorChanged( const QColor
 //  QColor newColor( newBackgroundColor );
   mItem->beginCommand( tr( "Background color changed" ) );
 //  newColor.setAlpha( 255 - ( mTransparencySpinBox->value() * 2.55 ) );
-  mItem->setBrush( QBrush( QColor( newBackgroundColor ), Qt::SolidPattern ) );
+  mItem->setBackgroundColor( newBackgroundColor );
+
   //if the item is a composer map, we need to regenerate the map image
   //because it usually is cached
   QgsComposerMap* cm = dynamic_cast<QgsComposerMap *>( mItem );
@@ -248,6 +249,15 @@ void QgsComposerItemWidget::on_mBackgroundGroupBox_toggled( bool state )
 
   mItem->beginCommand( tr( "Item background toggled" ) );
   mItem->setBackgroundEnabled( state );
+
+  //if the item is a composer map, we need to regenerate the map image
+  //because it usually is cached
+  QgsComposerMap* cm = dynamic_cast<QgsComposerMap *>( mItem );
+  if ( cm )
+  {
+    cm->cache();
+  }
+
   mItem->update();
   mItem->endCommand();
 }
diff --git a/src/core/composer/qgscomposeritem.cpp b/src/core/composer/qgscomposeritem.cpp
@@ -51,6 +51,7 @@ QgsComposerItem::QgsComposerItem( QgsComposition* composition, bool manageZValue
     , mVAlignSnapItem( 0 )
     , mFrame( false )
     , mBackground( true )
+    , mBackgroundColor( QColor( 255, 255, 255, 255 ) )
     , mItemPositionLocked( false )
     , mLastValidViewScaleFactor( -1 )
     , mRotation( 0 )
@@ -72,6 +73,7 @@ QgsComposerItem::QgsComposerItem( qreal x, qreal y, qreal width, qreal height, Q
     , mVAlignSnapItem( 0 )
     , mFrame( false )
     , mBackground( true )
+    , mBackgroundColor( QColor( 255, 255, 255, 255 ) )
     , mItemPositionLocked( false )
     , mLastValidViewScaleFactor( -1 )
     , mRotation( 0 )
@@ -326,7 +328,7 @@ bool QgsComposerItem::_readXML( const QDomElement& itemElem, const QDomDocument&
     if ( redOk && greenOk && blueOk && alphaOk )
     {
       QColor brushColor( bgRed, bgGreen, bgBlue, bgAlpha );
-      setBrush( QBrush( brushColor ) );
+      setBackgroundColor( brushColor );
     }
   }
 
@@ -884,6 +886,12 @@ void QgsComposerItem::drawBackground( QPainter* p )
   }
 }
 
+void QgsComposerItem::setBackgroundColor( const QColor& backgroundColor )
+{
+  mBackgroundColor = backgroundColor;
+  setBrush( QBrush( mBackgroundColor, Qt::SolidPattern ) );
+}
+
 void QgsComposerItem::setBlendMode( QPainter::CompositionMode blendMode )
 {
   mBlendMode = blendMode;
diff --git a/src/core/composer/qgscomposeritem.h b/src/core/composer/qgscomposeritem.h
@@ -197,6 +197,19 @@ class CORE_EXPORT QgsComposerItem: public QObject, public QGraphicsRectItem
      */
     void setBackgroundEnabled( bool drawBackground ) {mBackground = drawBackground;}
 
+    /** Gets the background color for this item
+     * @returns background color
+     * @note introduced in 2.0
+     */
+    QColor backgroundColor() const { return mBackgroundColor; }
+
+    /** Sets the background color for this item
+     * @param backgroundColor new background color
+     * @returns nothing
+     * @note introduced in 2.0
+     */
+    void setBackgroundColor( const QColor& backgroundColor );
+
     /** Returns the item's composition blending mode */
     QPainter::CompositionMode blendMode() const {return mBlendMode;}
 
@@ -309,6 +322,8 @@ class CORE_EXPORT QgsComposerItem: public QObject, public QGraphicsRectItem
     bool mFrame;
     /**True if item background needs to be painted*/
     bool mBackground;
+    /**Background color*/
+    QColor mBackgroundColor;
 
     /**True if item position  and size cannot be changed with mouse move
     @note: this member was added in version 1.2*/
diff --git a/src/core/composer/qgscomposermap.cpp b/src/core/composer/qgscomposermap.cpp
@@ -228,7 +228,18 @@ void QgsComposerMap::cache( void )
   double forcedWidthScaleFactor = w / requestExtent.width() / mapUnitsToMM();
 
   mCacheImage = QImage( w, h,  QImage::Format_ARGB32 );
-  mCacheImage.fill( QColor( 255, 255, 255, 0 ).rgba() ); // the background is drawn by composerItem, but we still need to start with that empty fill to avoid artifacts
+
+  if ( hasBackground() )
+  {
+    //Initially fill image with specified background color. This ensures that layers with blend modes will
+    //preview correctly
+    mCacheImage.fill( backgroundColor().rgba() );
+  }
+  else
+  {
+    //no background, but start with empty fill to avoid artifacts
+    mCacheImage.fill( QColor( 255, 255, 255, 0 ).rgba() );
+  }
 
   double mapUnitsPerPixel = mExtent.width() / w;
 
@@ -257,10 +268,10 @@ void QgsComposerMap::paint( QPainter* painter, const QStyleOptionGraphicsItem* i
   painter->save();
   painter->setClipRect( thisPaintRect );
 
-  drawBackground( painter );
-
   if ( mComposition->plotStyle() == QgsComposition::Preview && mPreviewMode == Rectangle )
   {
+    // Fill with background color
+    drawBackground( painter );
     QFont messageFont( "", 12 );
     painter->setFont( messageFont );
     painter->setPen( QColor( 0, 0, 0 ) );
@@ -272,6 +283,8 @@ 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;
     requestedExtent( requestRectangle );
@@ -323,6 +336,9 @@ void QgsComposerMap::paint( QPainter* painter, const QStyleOptionGraphicsItem* i
       return;
     }
 
+    // Fill with background color
+    drawBackground( painter );
+
     QgsRectangle requestRectangle;
     requestedExtent( requestRectangle );
 

Original file line number	Diff line number	Diff line change
`@@ -51,6 +51,7 @@ QgsComposerItem::QgsComposerItem( QgsComposition* composition, bool manageZValue`
`51`	`51`	`, mVAlignSnapItem( 0 )`
`52`	`52`	`, mFrame( false )`
`53`	`53`	`, mBackground( true )`
	`54`	`+ , mBackgroundColor( QColor( 255, 255, 255, 255 ) )`
`54`	`55`	`, mItemPositionLocked( false )`
`55`	`56`	`, mLastValidViewScaleFactor( -1 )`
`56`	`57`	`, mRotation( 0 )`
`@@ -72,6 +73,7 @@ QgsComposerItem::QgsComposerItem( qreal x, qreal y, qreal width, qreal height, Q`
`72`	`73`	`, mVAlignSnapItem( 0 )`
`73`	`74`	`, mFrame( false )`
`74`	`75`	`, mBackground( true )`
	`76`	`+ , mBackgroundColor( QColor( 255, 255, 255, 255 ) )`
`75`	`77`	`, mItemPositionLocked( false )`
`76`	`78`	`, mLastValidViewScaleFactor( -1 )`
`77`	`79`	`, mRotation( 0 )`
`@@ -326,7 +328,7 @@ bool QgsComposerItem::_readXML( const QDomElement& itemElem, const QDomDocument&`
`326`	`328`	`if ( redOk && greenOk && blueOk && alphaOk )`
`327`	`329`	`{`
`328`	`330`	`QColor brushColor( bgRed, bgGreen, bgBlue, bgAlpha );`
`329`		`- setBrush( QBrush( brushColor ) );`
	`331`	`+ setBackgroundColor( brushColor );`
`330`	`332`	`}`
`331`	`333`	`}`
`332`	`334`
`@@ -884,6 +886,12 @@ void QgsComposerItem::drawBackground( QPainter* p )`
`884`	`886`	`}`
`885`	`887`	`}`
`886`	`888`
	`889`	`+void QgsComposerItem::setBackgroundColor( const QColor& backgroundColor )`
	`890`	`+{`
	`891`	`+ mBackgroundColor = backgroundColor;`
	`892`	`+ setBrush( QBrush( mBackgroundColor, Qt::SolidPattern ) );`
	`893`	`+}`
	`894`	`+`
`887`	`895`	`void QgsComposerItem::setBlendMode( QPainter::CompositionMode blendMode )`
`888`	`896`	`{`
`889`	`897`	`mBlendMode = blendMode;`