Cache painter path for font marker when it doesn't change

Speeds up font marker rendering by around 2x
qgis · Jul 23, 2019 · 2dfcfda · 2dfcfda
1 parent eeb2e2a
commit 2dfcfda
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Showing 2 changed files with 27 additions and 5 deletions.
diff --git a/src/core/symbology/qgsmarkersymbollayer.cpp b/src/core/symbology/qgsmarkersymbollayer.cpp
@@ -2645,6 +2645,17 @@ void QgsFontMarkerSymbolLayer::startRender( QgsSymbolRenderContext &context )
   mChrWidth = mFontMetrics->width( mChr );
   mChrOffset = QPointF( mChrWidth / 2.0, -mFontMetrics->ascent() / 2.0 );
   mOrigSize = mSize; // save in case the size would be data defined
+
+  // use caching only when not using a data defined character
+  mUseCachedPath = !mDataDefinedProperties.isActive( QgsSymbolLayer::PropertyCharacter );
+  if ( mUseCachedPath )
+  {
+    QPointF chrOffset = mChrOffset;
+    double chrWidth;
+    QString charToRender = characterToRender( context, chrOffset, chrWidth );
+    mCachedPath = QPainterPath();
+    mCachedPath.addText( -chrOffset.x(), -chrOffset.y(), mFont, charToRender );
+  }
 }
 
 void QgsFontMarkerSymbolLayer::stopRender( QgsSymbolRenderContext &context )
@@ -2789,6 +2800,7 @@ void QgsFontMarkerSymbolLayer::renderPoint( QPointF point, QgsSymbolRenderContex
     }
   }
 
+  p->save();
   p->setBrush( mBrush );
   if ( !qgsDoubleNear( penWidth, 0.0 ) )
   {
@@ -2800,7 +2812,6 @@ void QgsFontMarkerSymbolLayer::renderPoint( QPointF point, QgsSymbolRenderContex
   {
     p->setPen( Qt::NoPen );
   }
-  p->save();
 
   QPointF chrOffset = mChrOffset;
   double chrWidth;
@@ -2813,7 +2824,7 @@ void QgsFontMarkerSymbolLayer::renderPoint( QPointF point, QgsSymbolRenderContex
   double angle = 0;
   calculateOffsetAndRotation( context, sizeToRender, hasDataDefinedRotation, offset, angle );
 
-  transform.translate( point.x() + offset.x(), point.y() + offset.y() );
+  p->translate( point.x() + offset.x(), point.y() + offset.y() );
 
   if ( !qgsDoubleNear( angle, 0.0 ) )
     transform.rotate( angle );
@@ -2824,9 +2835,17 @@ void QgsFontMarkerSymbolLayer::renderPoint( QPointF point, QgsSymbolRenderContex
     transform.scale( s, s );
   }
 
-  QPainterPath path;
-  path.addText( -chrOffset.x(), -chrOffset.y(), mFont, charToRender );
-  p->drawPath( transform.map( path ) );
+  if ( mUseCachedPath )
+  {
+    p->drawPath( transform.map( mCachedPath ) );
+  }
+  else
+  {
+    QPainterPath path;
+    path.addText( -chrOffset.x(), -chrOffset.y(), mFont, charToRender );
+    p->drawPath( transform.map( path ) );
+  }
+
   p->restore();
 }
 

diff --git a/src/core/symbology/qgsmarkersymbollayer.h b/src/core/symbology/qgsmarkersymbollayer.h
@@ -833,6 +833,9 @@ class CORE_EXPORT QgsFontMarkerSymbolLayer : public QgsMarkerSymbolLayer
     QPen mPen;
     QBrush mBrush;
 
+    bool mUseCachedPath = false;
+    QPainterPath mCachedPath;
+
     QString characterToRender( QgsSymbolRenderContext &context, QPointF &charOffset, double &charWidth );
     void calculateOffsetAndRotation( QgsSymbolRenderContext &context, double scaledSize, bool &hasDataDefinedRotation, QPointF &offset, double &angle ) const;
     double calculateSize( QgsSymbolRenderContext &context );