[feature][callouts] Add blending mode settings

qgis · Apr 26, 2021 · 9989cff · 9989cff
1 parent f93b738
commit 9989cff
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Showing 15 changed files with 272 additions and 4 deletions.
diff --git a/python/core/auto_generated/callouts/qgscallout.sip.in b/python/core/auto_generated/callouts/qgscallout.sip.in
@@ -10,6 +10,7 @@
 
 
 
+
 class QgsCallout
 {
 %Docstring(signature="appended")
@@ -66,6 +67,7 @@ relevant symbology elements to render them.
       Margins,
       WedgeWidth,
       CornerRadius,
+      BlendMode,
     };
 
     enum DrawOrder
@@ -156,6 +158,14 @@ Restores the callout's properties from a DOM element.
 The default behavior is the read the DOM contents and call :py:func:`~QgsCallout.readProperties` on the subclass.
 
 .. seealso:: :py:func:`readProperties`
+%End
+
+    bool containsAdvancedEffects() const;
+%Docstring
+Returns ``True`` if the callout requires advanced effects such as blend modes, which require
+output in raster formats to be fully respected.
+
+.. versionadded:: 3.20
 %End
 
     virtual void startRender( QgsRenderContext &context );
@@ -390,6 +400,24 @@ anchor point.
 .. seealso:: :py:func:`encodeLabelAnchorPoint`
 
 .. versionadded:: 3.14
+%End
+
+    QPainter::CompositionMode blendMode() const;
+%Docstring
+Returns the blending mode used for drawing callouts.
+
+.. seealso:: :py:func:`setBlendMode`
+
+.. versionadded:: 3.20
+%End
+
+    void setBlendMode( QPainter::CompositionMode mode );
+%Docstring
+Sets the blending ``mode`` used for drawing callouts.
+
+.. seealso:: :py:func:`blendMode`
+
+.. versionadded:: 3.20
 %End
 
   protected:

diff --git a/python/core/auto_generated/labeling/qgspallabeling.sip.in b/python/core/auto_generated/labeling/qgspallabeling.sip.in
@@ -290,6 +290,14 @@ Finalises the label settings after use.
 This must be called after a call to :py:func:`~QgsPalLayerSettings.startRender`, in order to gracefully clean up symbols.
 
 .. versionadded:: 3.10
+%End
+
+    bool containsAdvancedEffects() const;
+%Docstring
+Returns ``True`` if any component of the label settings requires advanced effects
+such as blend modes, which require output in raster formats to be fully respected.
+
+.. versionadded:: 3.20
 %End
 
     static const QgsPropertiesDefinition &propertyDefinitions();

diff --git a/src/core/callouts/qgscallout.cpp b/src/core/callouts/qgscallout.cpp
@@ -28,7 +28,8 @@
 #include "qgsgeometryutils.h"
 #include "qgscircularstring.h"
 #include "qgsshapegenerator.h"
-#include <QPainter>
+#include "qgspainting.h"
+
 #include <mutex>
 
 QgsPropertiesDefinition QgsCallout::sPropertyDefinitions;
@@ -64,6 +65,7 @@ void QgsCallout::initPropertyDefinitions()
     },
     { QgsCallout::WedgeWidth, QgsPropertyDefinition( "WedgeWidth", QObject::tr( "Wedge width" ), QgsPropertyDefinition::DoublePositive, origin ) },
     { QgsCallout::CornerRadius, QgsPropertyDefinition( "CornerRadius", QObject::tr( "Corner radius" ), QgsPropertyDefinition::DoublePositive, origin ) },
+    { QgsCallout::BlendMode, QgsPropertyDefinition( "BlendMode", QObject::tr( "Callout blend mode" ), QgsPropertyDefinition::BlendMode, origin ) },
   };
 }
 
@@ -78,6 +80,7 @@ QVariantMap QgsCallout::properties( const QgsReadWriteContext & ) const
   props.insert( QStringLiteral( "enabled" ), mEnabled ? "1" : "0" );
   props.insert( QStringLiteral( "anchorPoint" ), encodeAnchorPoint( mAnchorPoint ) );
   props.insert( QStringLiteral( "labelAnchorPoint" ), encodeLabelAnchorPoint( mLabelAnchorPoint ) );
+  props.insert( QStringLiteral( "blendMode" ), QgsPainting::getBlendModeEnum( mBlendMode ) );
   props.insert( QStringLiteral( "ddProperties" ), mDataDefinedProperties.toVariant( propertyDefinitions() ) );
   return props;
 }
@@ -87,6 +90,8 @@ void QgsCallout::readProperties( const QVariantMap &props, const QgsReadWriteCon
   mEnabled = props.value( QStringLiteral( "enabled" ), QStringLiteral( "0" ) ).toInt();
   mAnchorPoint = decodeAnchorPoint( props.value( QStringLiteral( "anchorPoint" ), QString() ).toString() );
   mLabelAnchorPoint = decodeLabelAnchorPoint( props.value( QStringLiteral( "labelAnchorPoint" ), QString() ).toString() );
+  mBlendMode = QgsPainting::getCompositionMode(
+                 static_cast< QgsPainting::BlendMode >( props.value( QStringLiteral( "blendMode" ), QString::number( QgsPainting::BlendNormal ) ).toUInt() ) );
   mDataDefinedProperties.loadVariant( props.value( QStringLiteral( "ddProperties" ) ), propertyDefinitions() );
 }
 
@@ -122,6 +127,11 @@ void QgsCallout::stopRender( QgsRenderContext & )
 
 }
 
+bool QgsCallout::containsAdvancedEffects() const
+{
+  return mBlendMode != QPainter::CompositionMode_SourceOver || dataDefinedProperties().isActive( QgsCallout::BlendMode );
+}
+
 QSet<QString> QgsCallout::referencedFields( const QgsRenderContext &context ) const
 {
   mDataDefinedProperties.prepare( context.expressionContext() );
@@ -135,8 +145,21 @@ QgsCallout::DrawOrder QgsCallout::drawOrder() const
 
 void QgsCallout::render( QgsRenderContext &context, const QRectF &rect, const double angle, const QgsGeometry &anchor, QgsCalloutContext &calloutContext )
 {
-#if 0 // for debugging
   QPainter *painter = context.painter();
+  if ( context.useAdvancedEffects() )
+  {
+
+    QPainter::CompositionMode blendMode = mBlendMode;
+    if ( dataDefinedProperties().isActive( QgsCallout::BlendMode ) )
+    {
+      context.expressionContext().setOriginalValueVariable( QString() );
+      mBlendMode = QgsSymbolLayerUtils::decodeBlendMode( dataDefinedProperties().valueAsString( QgsCallout::BlendMode, context.expressionContext(), QString() ) );
+    }
+
+    painter->setCompositionMode( blendMode );
+  }
+
+#if 0 // for debugging
   painter->save();
   painter->setRenderHint( QPainter::Antialiasing, false );
   painter->translate( rect.center() );
@@ -155,6 +178,8 @@ void QgsCallout::render( QgsRenderContext &context, const QRectF &rect, const do
 #endif
 
   draw( context, rect, angle, anchor, calloutContext );
+
+  painter->setCompositionMode( QPainter::CompositionMode_SourceOver ); // just to be sure
 }
 
 void QgsCallout::setEnabled( bool enabled )

diff --git a/src/core/callouts/qgscallout.h b/src/core/callouts/qgscallout.h
@@ -25,6 +25,8 @@
 #include "qgsmapunitscale.h"
 #include "qgscalloutposition.h"
 #include "qgsmargins.h"
+
+#include <QPainter>
 #include <QString>
 #include <QRectF>
 #include <memory>
@@ -94,6 +96,7 @@ class CORE_EXPORT QgsCallout
       Margins, //!< Margin from text (since QGIS 3.20)
       WedgeWidth, //!< Balloon callout wedge width (since QGIS 3.20)
       CornerRadius, //!< Balloon callout corner radius (since QGIS 3.20)
+      BlendMode, //!< Callout blend mode (since QGIS 3.20)
     };
 
     //! Options for draw order (stacking) of callouts
@@ -189,6 +192,13 @@ class CORE_EXPORT QgsCallout
      */
     virtual void restoreProperties( const QDomElement &element, const QgsReadWriteContext &context );
 
+    /**
+     * Returns TRUE if the callout requires advanced effects such as blend modes, which require
+     * output in raster formats to be fully respected.
+     * \since QGIS 3.20
+     */
+    bool containsAdvancedEffects() const;
+
     /**
      * Prepares the callout for rendering on the specified render \a context.
      *
@@ -409,6 +419,20 @@ class CORE_EXPORT QgsCallout
      */
     static QgsCallout::LabelAnchorPoint decodeLabelAnchorPoint( const QString &name, bool *ok = nullptr );
 
+    /**
+     * Returns the blending mode used for drawing callouts.
+     * \see setBlendMode()
+     * \since QGIS 3.20
+     */
+    QPainter::CompositionMode blendMode() const { return mBlendMode; }
+
+    /**
+     * Sets the blending \a mode used for drawing callouts.
+     * \see blendMode()
+     * \since QGIS 3.20
+     */
+    void setBlendMode( QPainter::CompositionMode mode ) { mBlendMode = mode; }
+
   protected:
 
     /**
@@ -465,6 +489,8 @@ class CORE_EXPORT QgsCallout
     AnchorPoint mAnchorPoint = PoleOfInaccessibility;
     LabelAnchorPoint mLabelAnchorPoint = LabelPointOnExterior;
 
+    QPainter::CompositionMode mBlendMode = QPainter::CompositionMode_SourceOver;
+
     //! Property collection for data defined callout settings
     QgsPropertyCollection mDataDefinedProperties;
 

diff --git a/src/core/labeling/qgspallabeling.cpp b/src/core/labeling/qgspallabeling.cpp
@@ -563,6 +563,11 @@ void QgsPalLayerSettings::stopRender( QgsRenderContext &context )
   mRenderStarted = false;
 }
 
+bool QgsPalLayerSettings::containsAdvancedEffects() const
+{
+  return mFormat.containsAdvancedEffects() || mCallout->containsAdvancedEffects();
+}
+
 QgsPalLayerSettings::~QgsPalLayerSettings()
 {
   if ( mRenderStarted )

diff --git a/src/core/labeling/qgspallabeling.h b/src/core/labeling/qgspallabeling.h
@@ -396,6 +396,13 @@ class CORE_EXPORT QgsPalLayerSettings
      */
     void stopRender( QgsRenderContext &context );
 
+    /**
+     * Returns TRUE if any component of the label settings requires advanced effects
+     * such as blend modes, which require output in raster formats to be fully respected.
+     * \since QGIS 3.20
+     */
+    bool containsAdvancedEffects() const;
+
     /**
      * Returns the labeling property definitions.
      * \since QGIS 3.0

diff --git a/src/core/labeling/qgsvectorlayerlabeling.cpp b/src/core/labeling/qgsvectorlayerlabeling.cpp
@@ -94,7 +94,7 @@ bool QgsVectorLayerSimpleLabeling::accept( QgsStyleEntityVisitorInterface *visit
 
 bool QgsVectorLayerSimpleLabeling::requiresAdvancedEffects() const
 {
-  return mSettings->format().containsAdvancedEffects();
+  return mSettings->containsAdvancedEffects();
 }
 
 QgsVectorLayerSimpleLabeling *QgsVectorLayerSimpleLabeling::create( const QDomElement &element, const QgsReadWriteContext &context )

diff --git a/src/gui/callouts/qgscalloutwidget.cpp b/src/gui/callouts/qgscalloutwidget.cpp
@@ -174,6 +174,8 @@ QgsSimpleLineCalloutWidget::QgsSimpleLineCalloutWidget( QgsVectorLayer *vl, QWid
   connect( mLabelAnchorPointComboBox, static_cast<void ( QComboBox::* )( int )>( &QComboBox::currentIndexChanged ), this, &QgsSimpleLineCalloutWidget::mLabelAnchorPointComboBox_currentIndexChanged );
 
   connect( mCalloutLineStyleButton, &QgsSymbolButton::changed, this, &QgsSimpleLineCalloutWidget::lineSymbolChanged );
+
+  connect( mCalloutBlendComboBox, static_cast<void ( QComboBox::* )( int )>( &QComboBox::currentIndexChanged ), this, &QgsSimpleLineCalloutWidget::mCalloutBlendComboBox_currentIndexChanged );
 }
 
 void QgsSimpleLineCalloutWidget::setCallout( QgsCallout *callout )
@@ -210,12 +212,15 @@ void QgsSimpleLineCalloutWidget::setCallout( QgsCallout *callout )
   whileBlocking( mAnchorPointComboBox )->setCurrentIndex( mAnchorPointComboBox->findData( static_cast< int >( callout->anchorPoint() ) ) );
   whileBlocking( mLabelAnchorPointComboBox )->setCurrentIndex( mLabelAnchorPointComboBox->findData( static_cast< int >( callout->labelAnchorPoint() ) ) );
 
+  whileBlocking( mCalloutBlendComboBox )->setBlendMode( mCallout->blendMode() );
+
   registerDataDefinedButton( mMinCalloutLengthDDBtn, QgsCallout::MinimumCalloutLength );
   registerDataDefinedButton( mOffsetFromAnchorDDBtn, QgsCallout::OffsetFromAnchor );
   registerDataDefinedButton( mOffsetFromLabelDDBtn, QgsCallout::OffsetFromLabel );
   registerDataDefinedButton( mDrawToAllPartsDDBtn, QgsCallout::DrawCalloutToAllParts );
   registerDataDefinedButton( mAnchorPointDDBtn, QgsCallout::AnchorPointPosition );
   registerDataDefinedButton( mLabelAnchorPointDDBtn, QgsCallout::LabelAnchorPointPosition );
+  registerDataDefinedButton( mCalloutBlendModeDDBtn, QgsCallout::BlendMode );
 
   registerDataDefinedButton( mOriginXDDBtn, QgsCallout::OriginX );
   registerDataDefinedButton( mOriginYDDBtn, QgsCallout::OriginY );
@@ -296,6 +301,12 @@ void QgsSimpleLineCalloutWidget::mLabelAnchorPointComboBox_currentIndexChanged(
   emit changed();
 }
 
+void QgsSimpleLineCalloutWidget::mCalloutBlendComboBox_currentIndexChanged( int )
+{
+  mCallout->setBlendMode( mCalloutBlendComboBox->blendMode() );
+  emit changed();
+}
+
 void QgsSimpleLineCalloutWidget::drawToAllPartsToggled( bool active )
 {
   mCallout->setDrawCalloutToAllParts( active );
@@ -384,6 +395,7 @@ QgsCurvedLineCalloutWidget::QgsCurvedLineCalloutWidget( QgsVectorLayer *vl, QWid
     emit changed();
   } );
 
+  connect( mCalloutBlendComboBox, static_cast<void ( QComboBox::* )( int )>( &QComboBox::currentIndexChanged ), this, &QgsCurvedLineCalloutWidget::mCalloutBlendComboBox_currentIndexChanged );
 }
 
 void QgsCurvedLineCalloutWidget::setCallout( QgsCallout *callout )
@@ -422,6 +434,8 @@ void QgsCurvedLineCalloutWidget::setCallout( QgsCallout *callout )
   whileBlocking( mAnchorPointComboBox )->setCurrentIndex( mAnchorPointComboBox->findData( static_cast< int >( callout->anchorPoint() ) ) );
   whileBlocking( mLabelAnchorPointComboBox )->setCurrentIndex( mLabelAnchorPointComboBox->findData( static_cast< int >( callout->labelAnchorPoint() ) ) );
 
+  whileBlocking( mCalloutBlendComboBox )->setBlendMode( mCallout->blendMode() );
+
   whileBlocking( mCurvatureSpinBox )->setValue( mCallout->curvature() * 100.0 );
   whileBlocking( mCurvatureSlider )->setValue( mCallout->curvature() * 1000.0 );
 
@@ -431,6 +445,7 @@ void QgsCurvedLineCalloutWidget::setCallout( QgsCallout *callout )
   registerDataDefinedButton( mDrawToAllPartsDDBtn, QgsCallout::DrawCalloutToAllParts );
   registerDataDefinedButton( mAnchorPointDDBtn, QgsCallout::AnchorPointPosition );
   registerDataDefinedButton( mLabelAnchorPointDDBtn, QgsCallout::LabelAnchorPointPosition );
+  registerDataDefinedButton( mCalloutBlendModeDDBtn, QgsCallout::BlendMode );
   registerDataDefinedButton( mCalloutCurvatureDDBtn, QgsCallout::Curvature );
   registerDataDefinedButton( mCalloutOrientationDDBtn, QgsCallout::Orientation );
 
@@ -513,6 +528,12 @@ void QgsCurvedLineCalloutWidget::mLabelAnchorPointComboBox_currentIndexChanged(
   emit changed();
 }
 
+void QgsCurvedLineCalloutWidget::mCalloutBlendComboBox_currentIndexChanged( int )
+{
+  mCallout->setBlendMode( mCalloutBlendComboBox->blendMode() );
+  emit changed();
+}
+
 void QgsCurvedLineCalloutWidget::drawToAllPartsToggled( bool active )
 {
   mCallout->setDrawCalloutToAllParts( active );
@@ -620,6 +641,8 @@ QgsBalloonCalloutWidget::QgsBalloonCalloutWidget( QgsVectorLayer *vl, QWidget *p
     mCallout->setCornerRadius( value );
     emit changed();
   } );
+
+  connect( mCalloutBlendComboBox, static_cast<void ( QComboBox::* )( int )>( &QComboBox::currentIndexChanged ), this, &QgsBalloonCalloutWidget::mCalloutBlendComboBox_currentIndexChanged );
 }
 
 void QgsBalloonCalloutWidget::setCallout( QgsCallout *callout )
@@ -659,8 +682,11 @@ void QgsBalloonCalloutWidget::setCallout( QgsCallout *callout )
 
   whileBlocking( mAnchorPointComboBox )->setCurrentIndex( mAnchorPointComboBox->findData( static_cast< int >( callout->anchorPoint() ) ) );
 
+  whileBlocking( mCalloutBlendComboBox )->setBlendMode( mCallout->blendMode() );
+
   registerDataDefinedButton( mOffsetFromAnchorDDBtn, QgsCallout::OffsetFromAnchor );
   registerDataDefinedButton( mAnchorPointDDBtn, QgsCallout::AnchorPointPosition );
+  registerDataDefinedButton( mCalloutBlendModeDDBtn, QgsCallout::BlendMode );
 
   registerDataDefinedButton( mDestXDDBtn, QgsCallout::DestinationX );
   registerDataDefinedButton( mDestYDDBtn, QgsCallout::DestinationY );
@@ -710,5 +736,11 @@ void QgsBalloonCalloutWidget::mAnchorPointComboBox_currentIndexChanged( int inde
   emit changed();
 }
 
+void QgsBalloonCalloutWidget::mCalloutBlendComboBox_currentIndexChanged( int )
+{
+  mCallout->setBlendMode( mCalloutBlendComboBox->blendMode() );
+  emit changed();
+}
+
 ///@endcond
 
diff --git a/src/gui/callouts/qgscalloutwidget.h b/src/gui/callouts/qgscalloutwidget.h
@@ -153,6 +153,7 @@ class GUI_EXPORT QgsSimpleLineCalloutWidget : public QgsCalloutWidget, private U
     void lineSymbolChanged();
     void mAnchorPointComboBox_currentIndexChanged( int index );
     void mLabelAnchorPointComboBox_currentIndexChanged( int index );
+    void mCalloutBlendComboBox_currentIndexChanged( int index );
     void drawToAllPartsToggled( bool active );
 
   private:
@@ -207,6 +208,7 @@ class GUI_EXPORT QgsCurvedLineCalloutWidget : public QgsCalloutWidget, private U
     void lineSymbolChanged();
     void mAnchorPointComboBox_currentIndexChanged( int index );
     void mLabelAnchorPointComboBox_currentIndexChanged( int index );
+    void mCalloutBlendComboBox_currentIndexChanged( int index );
     void drawToAllPartsToggled( bool active );
 
   private:
@@ -243,6 +245,7 @@ class GUI_EXPORT QgsBalloonCalloutWidget : public QgsCalloutWidget, private Ui::
     void offsetFromAnchorChanged();
     void fillSymbolChanged();
     void mAnchorPointComboBox_currentIndexChanged( int index );
+    void mCalloutBlendComboBox_currentIndexChanged( int index );
 
   private:
     std::unique_ptr< QgsBalloonCallout > mCallout;