void QgsMapRenderer::render( QPainter* painter, double* forceWidthScale )
{
//Lock render method for concurrent threads (e.g. from globe)
QMutexLocker renderLock( &mRenderMutex );
//flag to see if the render context has changed
//since the last time we rendered. If it hasnt changed we can
//take some shortcuts with rendering
bool mySameAsLastFlag = true;
QgsDebugMsg( "========== Rendering ==========" );
if ( mExtent.isEmpty() )
{
QgsDebugMsg( "empty extent... not rendering" );
return;
}
if ( mSize.width() == 1 && mSize.height() == 1 )
{
QgsDebugMsg( "size 1x1... not rendering" );
return;
}
QPaintDevice* thePaintDevice = painter->device();
if ( !thePaintDevice )
{
return;
}
// wait
if ( mDrawing )
{
QgsDebugMsg( "already rendering" );
QCoreApplication::processEvents();
}
if ( mDrawing )
{
QgsDebugMsg( "still rendering - skipping" );
return;
}
mDrawing = true;
const QgsCoordinateTransform *ct;
#ifdef QGISDEBUG
QgsDebugMsg( "Starting to render layer stack." );
QTime renderTime;
renderTime.start();
#endif
if ( mOverview )
mRenderContext.setDrawEditingInformation( !mOverview );
mRenderContext.setPainter( painter );
mRenderContext.setCoordinateTransform( 0 );
//this flag is only for stopping during the current rendering progress,
//so must be false at every new render operation
mRenderContext.setRenderingStopped( false );
// set selection color
QgsProject* prj = QgsProject::instance();
int myRed = prj->readNumEntry( "Gui", "/SelectionColorRedPart", 255 );
int myGreen = prj->readNumEntry( "Gui", "/SelectionColorGreenPart", 255 );
int myBlue = prj->readNumEntry( "Gui", "/SelectionColorBluePart", 0 );
int myAlpha = prj->readNumEntry( "Gui", "/SelectionColorAlphaPart", 255 );
mRenderContext.setSelectionColor( QColor( myRed, myGreen, myBlue, myAlpha ) );
//calculate scale factor
//use the specified dpi and not those from the paint device
//because sometimes QPainter units are in a local coord sys (e.g. in case of QGraphicsScene)
double sceneDpi = mScaleCalculator->dpi();
double scaleFactor = 1.0;
if ( mOutputUnits == QgsMapRenderer::Millimeters )
{
if ( forceWidthScale )
{
scaleFactor = *forceWidthScale;
}
else
{
scaleFactor = sceneDpi / 25.4;
}
}
double rasterScaleFactor = ( thePaintDevice->logicalDpiX() + thePaintDevice->logicalDpiY() ) / 2.0 / sceneDpi;
if ( mRenderContext.rasterScaleFactor() != rasterScaleFactor )
{
mRenderContext.setRasterScaleFactor( rasterScaleFactor );
mySameAsLastFlag = false;
}
if ( mRenderContext.scaleFactor() != scaleFactor )
{
mRenderContext.setScaleFactor( scaleFactor );
mySameAsLastFlag = false;
}
if ( mRenderContext.rendererScale() != mScale )
{
//add map scale to render context
mRenderContext.setRendererScale( mScale );
mySameAsLastFlag = false;
}
if ( mLastExtent != mExtent )
{
mLastExtent = mExtent;
mySameAsLastFlag = false;
}
mRenderContext.setLabelingEngine( mLabelingEngine );
if ( mLabelingEngine )
mLabelingEngine->init( this );
// know we know if this render is just a repeat of the last time, we
// can clear caches if it has changed
if ( !mySameAsLastFlag )
{
//clear the cache pixmap if we changed resolution / extent
QSettings mySettings;
if ( mySettings.value( "/qgis/enable_render_caching", false ).toBool() )
{
QgsMapLayerRegistry::instance()->clearAllLayerCaches();
}
}
// render all layers in the stack, starting at the base
QListIterator<QString> li( mLayerSet );
li.toBack();
QgsRectangle r1, r2;
while ( li.hasPrevious() )
{
if ( mRenderContext.renderingStopped() )
{
break;
}
// Store the painter in case we need to swap it out for the
// cache painter
QPainter * mypContextPainter = mRenderContext.painter();
// Flattened image for drawing when a blending mode is set
QImage * mypFlattenedImage = 0;
QString layerId = li.previous();
QgsDebugMsg( "Rendering at layer item " + layerId );
// This call is supposed to cause the progress bar to
// advance. However, it seems that updating the progress bar is
// incompatible with having a QPainter active (the one that is
// passed into this function), as Qt produces a number of errors
// when try to do so. I'm (Gavin) not sure how to fix this, but
// added these comments and debug statement to help others...
QgsDebugMsg( "If there is a QPaintEngine error here, it is caused by an emit call" );
//emit drawingProgress(myRenderCounter++, mLayerSet.size());
QgsMapLayer *ml = QgsMapLayerRegistry::instance()->mapLayer( layerId );
if ( !ml )
{
QgsDebugMsg( "Layer not found in registry!" );
continue;
}
QgsDebugMsg( QString( "layer %1: minscale:%2 maxscale:%3 scaledepvis:%4 extent:%5 blendmode:%6" )
.arg( ml->name() )
.arg( ml->minimumScale() )
.arg( ml->maximumScale() )
.arg( ml->hasScaleBasedVisibility() )
.arg( ml->extent().toString() )
.arg( ml->blendMode() )
);
if ( mRenderContext.useAdvancedEffects() )
{
// Set the QPainter composition mode so that this layer is rendered using
// the desired blending mode
mypContextPainter->setCompositionMode( ml->blendMode() );
}
if ( !ml->hasScaleBasedVisibility() || ( ml->minimumScale() <= mScale && mScale < ml->maximumScale() ) || mOverview )
{
connect( ml, SIGNAL( drawingProgress( int, int ) ), this, SLOT( onDrawingProgress( int, int ) ) );
//
// Now do the call to the layer that actually does
// the rendering work!
//
bool split = false;
if ( hasCrsTransformEnabled() )
{
r1 = mExtent;
split = splitLayersExtent( ml, r1, r2 );
ct = transformation( ml );
mRenderContext.setExtent( r1 );
QgsDebugMsg( " extent 1: " + r1.toString() );
QgsDebugMsg( " extent 2: " + r2.toString() );
if ( !r1.isFinite() || !r2.isFinite() ) //there was a problem transforming the extent. Skip the layer
{
continue;
}
}
else
{
ct = NULL;
}
mRenderContext.setCoordinateTransform( ct );
//decide if we have to scale the raster
//this is necessary in case QGraphicsScene is used
bool scaleRaster = false;
QgsMapToPixel rasterMapToPixel;
QgsMapToPixel bk_mapToPixel;
if ( ml->type() == QgsMapLayer::RasterLayer && qAbs( rasterScaleFactor - 1.0 ) > 0.000001 )
{
scaleRaster = true;
}
// Force render of layers that are being edited
// or if there's a labeling engine that needs the layer to register features
if ( ml->type() == QgsMapLayer::VectorLayer )
{
QgsVectorLayer* vl = qobject_cast<QgsVectorLayer *>( ml );
if ( vl->isEditable() ||
( mRenderContext.labelingEngine() && mRenderContext.labelingEngine()->willUseLayer( vl ) ) )
{
ml->setCacheImage( 0 );
}
}
QSettings mySettings;
bool useRenderCaching = false;
if ( ! split )//render caching does not yet cater for split extents
{
if ( mySettings.value( "/qgis/enable_render_caching", false ).toBool() )
{
useRenderCaching = true;
if ( !mySameAsLastFlag || ml->cacheImage() == 0 )
{
QgsDebugMsg( "Caching enabled but layer redraw forced by extent change or empty cache" );
QImage * mypImage = new QImage( mRenderContext.painter()->device()->width(),
mRenderContext.painter()->device()->height(), QImage::Format_ARGB32 );
if ( mypImage->isNull() )
{
QgsDebugMsg( "insufficient memory for image " + QString::number( mRenderContext.painter()->device()->width() ) + "x" + QString::number( mRenderContext.painter()->device()->height() ) );
emit drawError( ml );
painter->end(); // drawError is not caught by anyone, so we end painting to notify caller
return;
}
mypImage->fill( 0 );
ml->setCacheImage( mypImage ); //no need to delete the old one, maplayer does it for you
QPainter * mypPainter = new QPainter( ml->cacheImage() );
// Changed to enable anti aliasing by default in QGIS 1.7
if ( mySettings.value( "/qgis/enable_anti_aliasing", true ).toBool() )
{
mypPainter->setRenderHint( QPainter::Antialiasing );
}
mRenderContext.setPainter( mypPainter );
}
else if ( mySameAsLastFlag )
{
//draw from cached image
QgsDebugMsg( "Caching enabled --- drawing layer from cached image" );
mypContextPainter->drawImage( 0, 0, *( ml->cacheImage() ) );
disconnect( ml, SIGNAL( drawingProgress( int, int ) ), this, SLOT( onDrawingProgress( int, int ) ) );
//short circuit as there is nothing else to do...
continue;
}
}
}
// If we are drawing with an alternative blending mode then we need to render to a separate image
// before compositing this on the map. This effectively flattens the layer and prevents
// blending occuring between objects on the layer
// (this is not required for raster layers or when layer caching is enabled, since that has the same effect)
bool flattenedLayer = false;
if (( mRenderContext.useAdvancedEffects() ) && ( ml->type() == QgsMapLayer::VectorLayer ) )
{
QgsVectorLayer* vl = qobject_cast<QgsVectorLayer *>( ml );
if (( !useRenderCaching )
&& (( vl->blendMode() != QPainter::CompositionMode_SourceOver )
|| ( vl->featureBlendMode() != QPainter::CompositionMode_SourceOver )
|| ( vl->layerTransparency() != 0 ) ) )
{
flattenedLayer = true;
mypFlattenedImage = new QImage( mRenderContext.painter()->device()->width(),
mRenderContext.painter()->device()->height(), QImage::Format_ARGB32 );
if ( mypFlattenedImage->isNull() )
{
QgsDebugMsg( "insufficient memory for image " + QString::number( mRenderContext.painter()->device()->width() ) + "x" + QString::number( mRenderContext.painter()->device()->height() ) );
emit drawError( ml );
painter->end(); // drawError is not caught by anyone, so we end painting to notify caller
return;
}
mypFlattenedImage->fill( 0 );
QPainter * mypPainter = new QPainter( mypFlattenedImage );
if ( mySettings.value( "/qgis/enable_anti_aliasing", true ).toBool() )
{
mypPainter->setRenderHint( QPainter::Antialiasing );
}
mypPainter->scale( rasterScaleFactor, rasterScaleFactor );
mRenderContext.setPainter( mypPainter );
}
}
// Per feature blending mode
if (( mRenderContext.useAdvancedEffects() ) && ( ml->type() == QgsMapLayer::VectorLayer ) )
{
QgsVectorLayer* vl = qobject_cast<QgsVectorLayer *>( ml );
if ( vl->featureBlendMode() != QPainter::CompositionMode_SourceOver )
{
// set the painter to the feature blend mode, so that features drawn
// on this layer will interact and blend with each other
mRenderContext.painter()->setCompositionMode( vl->featureBlendMode() );
}
}
if ( scaleRaster )
{
bk_mapToPixel = mRenderContext.mapToPixel();
rasterMapToPixel = mRenderContext.mapToPixel();
rasterMapToPixel.setMapUnitsPerPixel( mRenderContext.mapToPixel().mapUnitsPerPixel() / rasterScaleFactor );
rasterMapToPixel.setYMaximum( mSize.height() * rasterScaleFactor );
mRenderContext.setMapToPixel( rasterMapToPixel );
mRenderContext.painter()->save();
mRenderContext.painter()->scale( 1.0 / rasterScaleFactor, 1.0 / rasterScaleFactor );
}
if ( !ml->draw( mRenderContext ) )
{
emit drawError( ml );
}
else
{
QgsDebugMsg( "Layer rendered without issues" );
}
if ( split )
{
mRenderContext.setExtent( r2 );
if ( !ml->draw( mRenderContext ) )
{
emit drawError( ml );
}
}
if ( scaleRaster )
{
mRenderContext.setMapToPixel( bk_mapToPixel );
mRenderContext.painter()->restore();
}
//apply layer transparency for vector layers
if (( mRenderContext.useAdvancedEffects() ) && ( ml->type() == QgsMapLayer::VectorLayer ) )
{
QgsVectorLayer* vl = qobject_cast<QgsVectorLayer *>( ml );
if ( vl->layerTransparency() != 0 )
{
// a layer transparency has been set, so update the alpha for the flattened layer
// by combining it with the layer transparency
QColor transparentFillColor = QColor( 0, 0, 0, 255 - ( 255 * vl->layerTransparency() / 100 ) );
// use destination in composition mode to merge source's alpha with destination
mRenderContext.painter()->setCompositionMode( QPainter::CompositionMode_DestinationIn );
mRenderContext.painter()->fillRect( 0, 0, mRenderContext.painter()->device()->width(),
mRenderContext.painter()->device()->height(), transparentFillColor );
}
}
if ( useRenderCaching )
{
// composite the cached image into our view and then clean up from caching
// by reinstating the painter as it was swapped out for caching renders
delete mRenderContext.painter();
mRenderContext.setPainter( mypContextPainter );
//draw from cached image that we created further up
if ( ml->cacheImage() )
mypContextPainter->drawImage( 0, 0, *( ml->cacheImage() ) );
}
else if ( flattenedLayer )
{
// If we flattened this layer for alternate blend modes, composite it now
delete mRenderContext.painter();
mRenderContext.setPainter( mypContextPainter );
mypContextPainter->save();
mypContextPainter->scale( 1.0 / rasterScaleFactor, 1.0 / rasterScaleFactor );
mypContextPainter->drawImage( 0, 0, *( mypFlattenedImage ) );
mypContextPainter->restore();
delete mypFlattenedImage;
mypFlattenedImage = 0;
}
disconnect( ml, SIGNAL( drawingProgress( int, int ) ), this, SLOT( onDrawingProgress( int, int ) ) );
}
void QgsMapRenderer::render( QPainter* painter )
{
//flag to see if the render context has changed
//since the last time we rendered. If it hasnt changed we can
//take some shortcuts with rendering
bool mySameAsLastFlag = true;
QgsDebugMsg( "========== Rendering ==========" );
if ( mExtent.isEmpty() )
{
QgsDebugMsg( "empty extent... not rendering" );
return;
}
if ( mSize.width() == 1 && mSize.height() == 1 )
{
QgsDebugMsg( "size 1x1... not rendering" );
return;
}
QPaintDevice* thePaintDevice = painter->device();
if ( !thePaintDevice )
{
return;
}
// wait
if ( mDrawing )
{
QgsDebugMsg( "already rendering" );
QCoreApplication::processEvents();
}
if ( mDrawing )
{
QgsDebugMsg( "still rendering - skipping" );
return;
}
mDrawing = true;
QgsCoordinateTransform* ct;
#ifdef QGISDEBUG
QgsDebugMsg( "Starting to render layer stack." );
QTime renderTime;
renderTime.start();
#endif
if ( mOverview )
mRenderContext.setDrawEditingInformation( !mOverview );
mRenderContext.setPainter( painter );
mRenderContext.setCoordinateTransform( 0 );
//this flag is only for stopping during the current rendering progress,
//so must be false at every new render operation
mRenderContext.setRenderingStopped( false );
//calculate scale factor
//use the specified dpi and not those from the paint device
//because sometimes QPainter units are in a local coord sys (e.g. in case of QGraphicsScene)
double sceneDpi = mScaleCalculator->dpi();
double scaleFactor = 1.0;
if ( mOutputUnits == QgsMapRenderer::Millimeters )
{
scaleFactor = sceneDpi / 25.4;
}
double rasterScaleFactor = ( thePaintDevice->logicalDpiX() + thePaintDevice->logicalDpiY() ) / 2.0 / sceneDpi;
if ( mRenderContext.rasterScaleFactor() != rasterScaleFactor )
{
mRenderContext.setRasterScaleFactor( rasterScaleFactor );
mySameAsLastFlag = false;
}
if ( mRenderContext.scaleFactor() != scaleFactor )
{
mRenderContext.setScaleFactor( scaleFactor );
mySameAsLastFlag = false;
}
if ( mRenderContext.rendererScale() != mScale )
{
//add map scale to render context
mRenderContext.setRendererScale( mScale );
mySameAsLastFlag = false;
}
if ( mLastExtent != mExtent )
{
mLastExtent = mExtent;
mySameAsLastFlag = false;
}
mRenderContext.setLabelingEngine( mLabelingEngine );
if ( mLabelingEngine )
mLabelingEngine->init( this );
// know we know if this render is just a repeat of the last time, we
// can clear caches if it has changed
if ( !mySameAsLastFlag )
{
//clear the cache pixmap if we changed resolution / extent
QSettings mySettings;
if ( mySettings.value( "/qgis/enable_render_caching", false ).toBool() )
{
QgsMapLayerRegistry::instance()->clearAllLayerCaches();
}
}
QgsOverlayObjectPositionManager* overlayManager = overlayManagerFromSettings();
QList<QgsVectorOverlay*> allOverlayList; //list of all overlays, used to draw them after layers have been rendered
// render all layers in the stack, starting at the base
QListIterator<QString> li( mLayerSet );
li.toBack();
QgsRectangle r1, r2;
while ( li.hasPrevious() )
{
if ( mRenderContext.renderingStopped() )
{
break;
}
// Store the painter in case we need to swap it out for the
// cache painter
QPainter * mypContextPainter = mRenderContext.painter();
QString layerId = li.previous();
QgsDebugMsg( "Rendering at layer item " + layerId );
// This call is supposed to cause the progress bar to
// advance. However, it seems that updating the progress bar is
// incompatible with having a QPainter active (the one that is
// passed into this function), as Qt produces a number of errors
// when try to do so. I'm (Gavin) not sure how to fix this, but
// added these comments and debug statement to help others...
QgsDebugMsg( "If there is a QPaintEngine error here, it is caused by an emit call" );
//emit drawingProgress(myRenderCounter++, mLayerSet.size());
QgsMapLayer *ml = QgsMapLayerRegistry::instance()->mapLayer( layerId );
if ( !ml )
{
QgsDebugMsg( "Layer not found in registry!" );
continue;
}
QgsDebugMsg( "Rendering layer " + ml->name() );
QgsDebugMsg( " Layer minscale " + QString( "%1" ).arg( ml->minimumScale() ) );
QgsDebugMsg( " Layer maxscale " + QString( "%1" ).arg( ml->maximumScale() ) );
QgsDebugMsg( " Scale dep. visibility enabled? " + QString( "%1" ).arg( ml->hasScaleBasedVisibility() ) );
QgsDebugMsg( " Input extent: " + ml->extent().toString() );
if ( !ml->hasScaleBasedVisibility() || ( ml->minimumScale() < mScale && mScale < ml->maximumScale() ) || mOverview )
{
connect( ml, SIGNAL( drawingProgress( int, int ) ), this, SLOT( onDrawingProgress( int, int ) ) );
//
// Now do the call to the layer that actually does
// the rendering work!
//
bool split = false;
if ( hasCrsTransformEnabled() )
{
r1 = mExtent;
split = splitLayersExtent( ml, r1, r2 );
ct = new QgsCoordinateTransform( ml->crs(), *mDestCRS );
mRenderContext.setExtent( r1 );
QgsDebugMsg( " extent 1: " + r1.toString() );
QgsDebugMsg( " extent 2: " + r2.toString() );
if ( !r1.isFinite() || !r2.isFinite() ) //there was a problem transforming the extent. Skip the layer
{
continue;
}
}
else
{
ct = NULL;
}
mRenderContext.setCoordinateTransform( ct );
//decide if we have to scale the raster
//this is necessary in case QGraphicsScene is used
bool scaleRaster = false;
QgsMapToPixel rasterMapToPixel;
QgsMapToPixel bk_mapToPixel;
if ( ml->type() == QgsMapLayer::RasterLayer && qAbs( rasterScaleFactor - 1.0 ) > 0.000001 )
{
scaleRaster = true;
}
//create overlay objects for features within the view extent
if ( ml->type() == QgsMapLayer::VectorLayer && overlayManager )
{
QgsVectorLayer* vl = qobject_cast<QgsVectorLayer *>( ml );
if ( vl )
{
QList<QgsVectorOverlay*> thisLayerOverlayList;
vl->vectorOverlays( thisLayerOverlayList );
QList<QgsVectorOverlay*>::iterator overlayIt = thisLayerOverlayList.begin();
for ( ; overlayIt != thisLayerOverlayList.end(); ++overlayIt )
{
if (( *overlayIt )->displayFlag() )
{
( *overlayIt )->createOverlayObjects( mRenderContext );
allOverlayList.push_back( *overlayIt );
}
}
overlayManager->addLayer( vl, thisLayerOverlayList );
}
}
// Force render of layers that are being edited
// or if there's a labeling engine that needs the layer to register features
if ( ml->type() == QgsMapLayer::VectorLayer )
{
QgsVectorLayer* vl = qobject_cast<QgsVectorLayer *>( ml );
if ( vl->isEditable() ||
( mRenderContext.labelingEngine() && mRenderContext.labelingEngine()->willUseLayer( vl ) ) )
{
ml->setCacheImage( 0 );
}
}
QSettings mySettings;
if ( ! split )//render caching does not yet cater for split extents
{
if ( mySettings.value( "/qgis/enable_render_caching", false ).toBool() )
{
if ( !mySameAsLastFlag || ml->cacheImage() == 0 )
{
QgsDebugMsg( "\n\n\nCaching enabled but layer redraw forced by extent change or empty cache\n\n\n" );
QImage * mypImage = new QImage( mRenderContext.painter()->device()->width(),
mRenderContext.painter()->device()->height(), QImage::Format_ARGB32 );
mypImage->fill( 0 );
ml->setCacheImage( mypImage ); //no need to delete the old one, maplayer does it for you
QPainter * mypPainter = new QPainter( ml->cacheImage() );
// Changed to enable anti aliasing by default in QGIS 1.7
if ( mySettings.value( "/qgis/enable_anti_aliasing", true ).toBool() )
{
mypPainter->setRenderHint( QPainter::Antialiasing );
}
mRenderContext.setPainter( mypPainter );
}
else if ( mySameAsLastFlag )
{
//draw from cached image
QgsDebugMsg( "\n\n\nCaching enabled --- drawing layer from cached image\n\n\n" );
mypContextPainter->drawImage( 0, 0, *( ml->cacheImage() ) );
disconnect( ml, SIGNAL( drawingProgress( int, int ) ), this, SLOT( onDrawingProgress( int, int ) ) );
//short circuit as there is nothing else to do...
continue;
}
}
}
if ( scaleRaster )
{
bk_mapToPixel = mRenderContext.mapToPixel();
rasterMapToPixel = mRenderContext.mapToPixel();
rasterMapToPixel.setMapUnitsPerPixel( mRenderContext.mapToPixel().mapUnitsPerPixel() / rasterScaleFactor );
rasterMapToPixel.setYMaximum( mSize.height() * rasterScaleFactor );
mRenderContext.setMapToPixel( rasterMapToPixel );
mRenderContext.painter()->save();
mRenderContext.painter()->scale( 1.0 / rasterScaleFactor, 1.0 / rasterScaleFactor );
}
if ( !ml->draw( mRenderContext ) )
{
emit drawError( ml );
}
else
{
QgsDebugMsg( "Layer rendered without issues" );
}
if ( split )
{
mRenderContext.setExtent( r2 );
if ( !ml->draw( mRenderContext ) )
{
emit drawError( ml );
}
}
if ( scaleRaster )
{
mRenderContext.setMapToPixel( bk_mapToPixel );
mRenderContext.painter()->restore();
}
if ( mySettings.value( "/qgis/enable_render_caching", false ).toBool() )
{
if ( !split )
{
// composite the cached image into our view and then clean up from caching
// by reinstating the painter as it was swapped out for caching renders
delete mRenderContext.painter();
mRenderContext.setPainter( mypContextPainter );
//draw from cached image that we created further up
mypContextPainter->drawImage( 0, 0, *( ml->cacheImage() ) );
}
}
disconnect( ml, SIGNAL( drawingProgress( int, int ) ), this, SLOT( onDrawingProgress( int, int ) ) );
}
else // layer not visible due to scale
{