Avoid trying to calculate excessively large spread/blurs in

preview icons for draw effects This can quasi-hang the QGIS interface Fixes #41149
qgis · Sep 27, 2021 · 49d4b95 · 49d4b95
1 parent 615f68a
commit 49d4b95
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Showing 5 changed files with 77 additions and 7 deletions.
diff --git a/src/core/effects/qgsblureffect.cpp b/src/core/effects/qgsblureffect.cpp
@@ -45,15 +45,29 @@ void QgsBlurEffect::draw( QgsRenderContext &context )
 
 void QgsBlurEffect::drawStackBlur( QgsRenderContext &context )
 {
-  const int blurLevel = std::round( context.convertToPainterUnits( mBlurLevel, mBlurUnit, mBlurMapUnitScale ) );
+  int blurLevel = std::round( context.convertToPainterUnits( mBlurLevel, mBlurUnit, mBlurMapUnitScale ) );
+  if ( context.flags() & QgsRenderContext::Flag::RenderSymbolPreview )
+  {
+    // avoid excessively large blur or offset in symbol preview icons -- it's too slow to calculate, and unnecessary
+    // for just a preview icon
+    blurLevel = std::min( blurLevel, 30 );
+  }
+
   QImage im = sourceAsImage( context )->copy();
   QgsImageOperation::stackBlur( im, blurLevel, false, context.feedback() );
   drawBlurredImage( context, im );
 }
 
 void QgsBlurEffect::drawGaussianBlur( QgsRenderContext &context )
 {
-  const int blurLevel = std::round( context.convertToPainterUnits( mBlurLevel, mBlurUnit, mBlurMapUnitScale ) );
+  int blurLevel = std::round( context.convertToPainterUnits( mBlurLevel, mBlurUnit, mBlurMapUnitScale ) );
+  if ( context.flags() & QgsRenderContext::Flag::RenderSymbolPreview )
+  {
+    // avoid excessively large blur or offset in symbol preview icons -- it's too slow to calculate, and unnecessary
+    // for just a preview icon
+    blurLevel = std::min( blurLevel, 30 );
+  }
+
   QImage *im = QgsImageOperation::gaussianBlur( *sourceAsImage( context ), blurLevel, context.feedback() );
   if ( !im->isNull() )
     drawBlurredImage( context, *im );
@@ -139,7 +153,15 @@ QgsBlurEffect *QgsBlurEffect::clone() const
 
 QRectF QgsBlurEffect::boundingRect( const QRectF &rect, const QgsRenderContext &context ) const
 {
-  const int blurLevel = std::round( context.convertToPainterUnits( mBlurLevel, mBlurUnit, mBlurMapUnitScale ) );
+  int blurLevel = std::round( context.convertToPainterUnits( mBlurLevel, mBlurUnit, mBlurMapUnitScale ) );
+
+  if ( context.flags() & QgsRenderContext::Flag::RenderSymbolPreview )
+  {
+    // avoid excessively large blur or offset in symbol preview icons -- it's too slow to calculate, and unnecessary
+    // for just a preview icon
+    blurLevel = std::min( blurLevel, 30 );
+  }
+
   //plus possible extension due to blur, with a couple of extra pixels thrown in for safety
   const double spread = blurLevel * 2.0 + 10;
   return rect.adjusted( -spread, -spread, spread, spread );

diff --git a/src/core/effects/qgsgloweffect.cpp b/src/core/effects/qgsgloweffect.cpp
@@ -60,6 +60,14 @@ void QgsGlowEffect::draw( QgsRenderContext &context )
     ramp = tempRamp.get();
   }
 
+  double spread = context.convertToPainterUnits( mSpread, mSpreadUnit, mSpreadMapUnitScale );
+  if ( context.flags() & QgsRenderContext::Flag::RenderSymbolPreview )
+  {
+    // avoid excessive spread in symbol preview icons -- it's too slow to calculate, and unnecessary
+    // for just a preview icon
+    spread = std::min( spread, 50.0 );
+  }
+
   QgsImageOperation::DistanceTransformProperties dtProps;
   dtProps.spread = context.convertToPainterUnits( mSpread, mSpreadUnit, mSpreadMapUnitScale );
   dtProps.useMaxDistance = false;
@@ -70,7 +78,14 @@ void QgsGlowEffect::draw( QgsRenderContext &context )
   if ( context.feedback() && context.feedback()->isCanceled() )
     return;
 
-  const int blurLevel = std::round( context.convertToPainterUnits( mBlurLevel, mBlurUnit, mBlurMapUnitScale ) );
+  int blurLevel = std::round( context.convertToPainterUnits( mBlurLevel, mBlurUnit, mBlurMapUnitScale ) );
+  if ( context.flags() & QgsRenderContext::Flag::RenderSymbolPreview )
+  {
+    // avoid excessive blur in symbol preview icons -- it's too slow to calculate, and unnecessary
+    // for just a preview icon
+    blurLevel = std::min( blurLevel, 30 );
+  }
+
   if ( blurLevel <= 16 )
   {
     QgsImageOperation::stackBlur( im, blurLevel, false, context.feedback() );
@@ -233,8 +248,17 @@ QgsGlowEffect &QgsGlowEffect::operator=( const QgsGlowEffect &rhs )
 QRectF QgsGlowEffect::boundingRect( const QRectF &rect, const QgsRenderContext &context ) const
 {
   //blur radius and spread size
-  const int blurLevel = std::round( context.convertToPainterUnits( mBlurLevel, mBlurUnit, mBlurMapUnitScale ) );
+  int blurLevel = std::round( context.convertToPainterUnits( mBlurLevel, mBlurUnit, mBlurMapUnitScale ) );
   double spread = context.convertToPainterUnits( mSpread, mSpreadUnit, mSpreadMapUnitScale );
+
+  if ( context.flags() & QgsRenderContext::Flag::RenderSymbolPreview )
+  {
+    // avoid excessively large blur or spread in symbol preview icons -- it's too slow to calculate, and unnecessary
+    // for just a preview icon
+    blurLevel = std::min( blurLevel, 30 );
+    spread = std::min( spread, 50.0 );
+  }
+
   //plus possible extension due to blur, with a couple of extra pixels thrown in for safety
   spread += blurLevel * 2 + 10;
   return rect.adjusted( -spread, -spread, spread, spread );

diff --git a/src/core/effects/qgsimageoperation.cpp b/src/core/effects/qgsimageoperation.cpp
@@ -717,6 +717,9 @@ void QgsImageOperation::GaussianBlurOperation::operator()( QgsImageOperation::Im
       destRef = reinterpret_cast< QRgb * >( outputLineRef );
       for ( int x = 0; x < width; ++x, ++destRef, sourceRef += 4 )
       {
+        if ( mFeedback && mFeedback->isCanceled() )
+          break;
+
         *destRef = gaussianBlurVertical( y, sourceRef, sourceBpl, height );
       }
     }
@@ -732,6 +735,9 @@ void QgsImageOperation::GaussianBlurOperation::operator()( QgsImageOperation::Im
       destRef = reinterpret_cast< QRgb * >( outputLineRef );
       for ( int x = 0; x < width; ++x, ++destRef )
       {
+        if ( mFeedback && mFeedback->isCanceled() )
+          break;
+
         *destRef = gaussianBlurHorizontal( x, sourceRef, width );
       }
     }

diff --git a/src/core/effects/qgsshadoweffect.cpp b/src/core/effects/qgsshadoweffect.cpp
@@ -52,7 +52,14 @@ void QgsShadowEffect::draw( QgsRenderContext &context )
 
   QgsImageOperation::overlayColor( colorisedIm, mColor );
 
-  const int blurLevel = std::round( context.convertToPainterUnits( mBlurLevel, mBlurUnit, mBlurMapUnitScale ) );
+  int blurLevel = std::round( context.convertToPainterUnits( mBlurLevel, mBlurUnit, mBlurMapUnitScale ) );
+  if ( context.flags() & QgsRenderContext::Flag::RenderSymbolPreview )
+  {
+    // avoid excessively large blur in symbol preview icons -- it's too slow to calculate, and unnecessary
+    // for just a preview icon
+    blurLevel = std::min( blurLevel, 30 );
+  }
+
   if ( blurLevel <= 16 )
   {
     QgsImageOperation::stackBlur( colorisedIm, blurLevel, false, context.feedback() );
@@ -174,8 +181,18 @@ void QgsShadowEffect::readProperties( const QVariantMap &props )
 QRectF QgsShadowEffect::boundingRect( const QRectF &rect, const QgsRenderContext &context ) const
 {
   //blur radius and offset distance
-  const int blurLevel = std::round( context.convertToPainterUnits( mBlurLevel, mBlurUnit, mBlurMapUnitScale ) );
+  int blurLevel = std::round( context.convertToPainterUnits( mBlurLevel, mBlurUnit, mBlurMapUnitScale ) );
+
   double spread = context.convertToPainterUnits( mOffsetDist, mOffsetUnit, mOffsetMapUnitScale );
+
+  if ( context.flags() & QgsRenderContext::Flag::RenderSymbolPreview )
+  {
+    // avoid excessively large blur or offset in symbol preview icons -- it's too slow to calculate, and unnecessary
+    // for just a preview icon
+    blurLevel = std::min( blurLevel, 30 );
+    spread = std::min( spread, 100.0 );
+  }
+
   //plus possible extension due to blur, with a couple of extra pixels thrown in for safety
   spread += blurLevel * 2 + 10;
   return rect.adjusted( -spread, -spread, spread, spread );

diff --git a/src/gui/effects/qgseffectstackpropertieswidget.cpp b/src/gui/effects/qgseffectstackpropertieswidget.cpp
@@ -211,6 +211,7 @@ void QgsEffectStackPropertiesWidget::updatePreview()
   painter.begin( &previewImage );
   painter.setRenderHint( QPainter::Antialiasing );
   QgsRenderContext context = QgsRenderContext::fromQPainter( &painter );
+  context.setFlag( QgsRenderContext::RenderSymbolPreview, true );
   if ( mPreviewPicture.isNull() )
   {
     QPicture previewPic;