[FEATURE] Paint effect support for label buffers

nyalldawson · nyalldawson · commit b9f102c98d72 · 2017-04-28T19:25:45.000+10:00
Allows applying a paint effect (such as blurs) to label buffers.
Blurring label buffers is a great way to get the text readability
of a label buffer without the distracting halo effect.
diff --git a/python/core/qgstextrenderer.sip b/python/core/qgstextrenderer.sip
@@ -130,7 +130,19 @@ class QgsTextBufferSettings
      */
     void setBlendMode( QPainter::CompositionMode mode );
 
-        /** Reads settings from a layer's custom properties.
+    /** Returns the current paint effect for the buffer.
+     * @returns paint effect
+     * @see setPaintEffect()
+     */
+    QgsPaintEffect* paintEffect() const;
+
+    /** Sets the current paint effect for the buffer.
+     * @param effect paint effect. Ownership is transferred to the buffer settings.
+     * @see paintEffect()
+     */
+    void setPaintEffect( QgsPaintEffect* effect /Transfer/ );
+
+    /** Reads settings from a layer's custom properties.
      * @param layer source vector layer
      * @see writeToLayer()
      */
diff --git a/src/core/qgstextrenderer.cpp b/src/core/qgstextrenderer.cpp
@@ -15,12 +15,14 @@
  ***************************************************************************/
 
 #include "qgstextrenderer.h"
+#include "qgis.h"
 #include "qgstextrenderer_p.h"
 #include "qgsfontutils.h"
 #include "qgsvectorlayer.h"
 #include "qgssymbollayerutils.h"
 #include "qgspainting.h"
 #include "qgsmarkersymbollayer.h"
+#include "qgspainteffectregistry.h"
 #include <QFontDatabase>
 
 Q_GUI_EXPORT extern int qt_defaultDpiX();
@@ -179,6 +181,17 @@ void QgsTextBufferSettings::setBlendMode( QPainter::CompositionMode mode )
   d->blendMode = mode;
 }
 
+QgsPaintEffect *QgsTextBufferSettings::paintEffect() const
+{
+  return d->paintEffect;
+}
+
+void QgsTextBufferSettings::setPaintEffect( QgsPaintEffect *effect )
+{
+  delete d->paintEffect;
+  d->paintEffect = effect;
+}
+
 void QgsTextBufferSettings::readFromLayer( QgsVectorLayer *layer )
 {
   // text buffer
@@ -236,6 +249,16 @@ void QgsTextBufferSettings::readFromLayer( QgsVectorLayer *layer )
   d->joinStyle = static_cast< Qt::PenJoinStyle >( layer->customProperty( QStringLiteral( "labeling/bufferJoinStyle" ), QVariant( Qt::RoundJoin ) ).toUInt() );
 
   d->fillBufferInterior = !layer->customProperty( QStringLiteral( "labeling/bufferNoFill" ), QVariant( false ) ).toBool();
+
+  if ( layer->customProperty( QStringLiteral( "labeling/bufferEffect" ) ).isValid() )
+  {
+    QDomDocument doc( QStringLiteral( "effect" ) );
+    doc.setContent( layer->customProperty( QStringLiteral( "labeling/bufferEffect" ) ).toString() );
+    QDomElement effectElem = doc.firstChildElement( QStringLiteral( "effect" ) ).firstChildElement( QStringLiteral( "effect" ) );
+    setPaintEffect( QgsApplication::paintEffectRegistry()->createEffect( effectElem ) );
+  }
+  else
+    setPaintEffect( nullptr );
 }
 
 void QgsTextBufferSettings::writeToLayer( QgsVectorLayer *layer ) const
@@ -249,6 +272,21 @@ void QgsTextBufferSettings::writeToLayer( QgsVectorLayer *layer ) const
   layer->setCustomProperty( QStringLiteral( "labeling/bufferOpacity" ), d->opacity );
   layer->setCustomProperty( QStringLiteral( "labeling/bufferJoinStyle" ), static_cast< unsigned int >( d->joinStyle ) );
   layer->setCustomProperty( QStringLiteral( "labeling/bufferBlendMode" ), QgsPainting::getBlendModeEnum( d->blendMode ) );
+
+  if ( d->paintEffect && !QgsPaintEffectRegistry::isDefaultStack( d->paintEffect ) )
+  {
+    QDomDocument doc( QStringLiteral( "effect" ) );
+    QDomElement effectElem = doc.createElement( QStringLiteral( "effect" ) );
+    d->paintEffect->saveProperties( doc, effectElem );
+    QString effectProps;
+    QTextStream stream( &effectProps );
+    effectElem.save( stream, -1 );
+    layer->setCustomProperty( QStringLiteral( "labeling/bufferEffect" ), effectProps );
+  }
+  else
+  {
+    layer->removeCustomProperty( QStringLiteral( "labeling/bufferEffect" ) );
+  }
 }
 
 void QgsTextBufferSettings::readXml( const QDomElement &elem )
@@ -309,6 +347,11 @@ void QgsTextBufferSettings::readXml( const QDomElement &elem )
                    static_cast< QgsPainting::BlendMode >( textBufferElem.attribute( QStringLiteral( "bufferBlendMode" ), QString::number( QgsPainting::BlendNormal ) ).toUInt() ) );
   d->joinStyle = static_cast< Qt::PenJoinStyle >( textBufferElem.attribute( QStringLiteral( "bufferJoinStyle" ), QString::number( Qt::RoundJoin ) ).toUInt() );
   d->fillBufferInterior = !textBufferElem.attribute( QStringLiteral( "bufferNoFill" ), QStringLiteral( "0" ) ).toInt();
+  QDomElement effectElem = textBufferElem.firstChildElement( QStringLiteral( "effect" ) );
+  if ( !effectElem.isNull() )
+    setPaintEffect( QgsApplication::paintEffectRegistry()->createEffect( effectElem ) );
+  else
+    setPaintEffect( nullptr );
 }
 
 QDomElement QgsTextBufferSettings::writeXml( QDomDocument &doc ) const
@@ -324,6 +367,8 @@ QDomElement QgsTextBufferSettings::writeXml( QDomDocument &doc ) const
   textBufferElem.setAttribute( QStringLiteral( "bufferOpacity" ), d->opacity );
   textBufferElem.setAttribute( QStringLiteral( "bufferJoinStyle" ), static_cast< unsigned int >( d->joinStyle ) );
   textBufferElem.setAttribute( QStringLiteral( "bufferBlendMode" ), QgsPainting::getBlendModeEnum( d->blendMode ) );
+  if ( d->paintEffect && !QgsPaintEffectRegistry::isDefaultStack( d->paintEffect ) )
+    d->paintEffect->saveProperties( doc, textBufferElem );
   return textBufferElem;
 }
 
@@ -1809,9 +1854,25 @@ void QgsTextRenderer::drawBuffer( QgsRenderContext &context, const QgsTextRender
   QPicture buffPict;
   QPainter buffp;
   buffp.begin( &buffPict );
-  buffp.setPen( pen );
-  buffp.setBrush( tmpColor );
-  buffp.drawPath( path );
+
+  if ( buffer.paintEffect() && buffer.paintEffect()->enabled() )
+  {
+    context.setPainter( &buffp );
+
+    buffer.paintEffect()->begin( context );
+    context.painter()->setPen( pen );
+    context.painter()->setBrush( tmpColor );
+    context.painter()->drawPath( path );
+    buffer.paintEffect()->end( context );
+
+    context.setPainter( p );
+  }
+  else
+  {
+    buffp.setPen( pen );
+    buffp.setBrush( tmpColor );
+    buffp.drawPath( path );
+  }
   buffp.end();
 
   if ( format.shadow().enabled() && format.shadow().shadowPlacement() == QgsTextShadowSettings::ShadowBuffer )
@@ -1822,7 +1883,6 @@ void QgsTextRenderer::drawBuffer( QgsRenderContext &context, const QgsTextRender
     bufferComponent.pictureBuffer = penSize / 2.0;
     drawShadow( context, bufferComponent, format );
   }
-
   p->save();
   if ( context.useAdvancedEffects() )
   {
@@ -2562,3 +2622,4 @@ void QgsTextRenderer::drawTextInternal( TextPart drawType,
     i++;
   }
 }
+
diff --git a/src/core/qgstextrenderer.h b/src/core/qgstextrenderer.h
@@ -31,6 +31,7 @@ class QgsTextBackgroundSettingsPrivate;
 class QgsTextShadowSettingsPrivate;
 class QgsTextSettingsPrivate;
 class QgsVectorLayer;
+class QgsPaintEffect;
 
 /** \class QgsTextBufferSettings
   * \ingroup core
@@ -191,6 +192,17 @@ class CORE_EXPORT QgsTextBufferSettings
      */
     QDomElement writeXml( QDomDocument &doc ) const;
 
+    /** Returns the current paint effect for the buffer.
+     * \returns paint effect
+     * \see setPaintEffect()
+     */
+    QgsPaintEffect *paintEffect() const;
+
+    /** Sets the current paint \a effect for the buffer.
+     * \param effect paint effect. Ownership is transferred to the buffer settings.
+     * \see paintEffect()
+     */
+    void setPaintEffect( QgsPaintEffect *effect );
 
   private:
 
diff --git a/src/core/qgstextrenderer_p.h b/src/core/qgstextrenderer_p.h
@@ -22,6 +22,7 @@
 #include "qgsmapunitscale.h"
 #include "qgsunittypes.h"
 #include "qgsapplication.h"
+#include "qgspainteffect.h"
 #include <QSharedData>
 #include <QPainter>
 
@@ -50,6 +51,7 @@ class CORE_EXPORT QgsTextBufferSettingsPrivate : public QSharedData
       , fillBufferInterior( false )
       , joinStyle( Qt::RoundJoin )
       , blendMode( QPainter::CompositionMode_SourceOver )
+      , paintEffect( nullptr )
     {
     }
 
@@ -64,9 +66,15 @@ class CORE_EXPORT QgsTextBufferSettingsPrivate : public QSharedData
       , fillBufferInterior( other.fillBufferInterior )
       , joinStyle( other.joinStyle )
       , blendMode( other.blendMode )
+      , paintEffect( other.paintEffect ? other.paintEffect->clone() : nullptr )
     {
     }
 
+    ~QgsTextBufferSettingsPrivate()
+    {
+      delete paintEffect;
+    }
+
     bool enabled;
     double size;
     QgsUnitTypes::RenderUnit sizeUnit;
@@ -76,6 +84,7 @@ class CORE_EXPORT QgsTextBufferSettingsPrivate : public QSharedData
     bool fillBufferInterior;
     Qt::PenJoinStyle joinStyle;
     QPainter::CompositionMode blendMode;
+    QgsPaintEffect *paintEffect;
 };
 
 
diff --git a/src/gui/effects/qgseffectstackpropertieswidget.cpp b/src/gui/effects/qgseffectstackpropertieswidget.cpp
@@ -467,7 +467,16 @@ void QgsEffectStackCompactWidget::showDialog()
   }
   connect( widget, &QgsPanelWidget::widgetChanged, this, &QgsEffectStackCompactWidget::updateEffectLive );
   connect( widget, &QgsPanelWidget::panelAccepted, this, &QgsEffectStackCompactWidget::updateAcceptWidget );
-  openPanel( widget );
+
+  QgsPanelWidget *panel = QgsPanelWidget::findParentPanel( qobject_cast< QWidget * >( parent() ) );
+  if ( panel && panel->dockMode() )
+  {
+    panel->openPanel( widget );
+  }
+  else
+  {
+    openPanel( widget );
+  }
 }
 
 void QgsEffectStackCompactWidget::enableToggled( bool checked )
diff --git a/src/gui/qgstextformatwidget.cpp b/src/gui/qgstextformatwidget.cpp
@@ -24,6 +24,8 @@
 #include "qgssubstitutionlistwidget.h"
 #include "qgspallabeling.h" // for enum values
 #include "qgssettings.h"
+#include "qgseffectstack.h"
+#include "qgspainteffectregistry.h"
 
 QgsTextFormatWidget::QgsTextFormatWidget( const QgsTextFormat &format, QgsMapCanvas *mapCanvas, QWidget *parent )
   : QWidget( parent )
@@ -259,6 +261,10 @@ void QgsTextFormatWidget::initWidget()
 
   mLabelingOptionsListWidget->setCurrentRow( settings.value( QStringLiteral( "Windows/Labeling/Tab" ), 0 ).toInt() );
 
+  mBufferEffect.reset( QgsPaintEffectRegistry::defaultStack() );
+  connect( mBufferEffectWidget, &QgsEffectStackCompactWidget::changed, this, &QgsTextFormatWidget::updatePreview );
+  mBufferEffectWidget->setPaintEffect( mBufferEffect.get() );
+
   setDockMode( false );
 
 
@@ -611,7 +617,14 @@ void QgsTextFormatWidget::updateWidgetForFormat( const QgsTextFormat &format )
   mBufferJoinStyleComboBox->setPenJoinStyle( buffer.joinStyle() );
   mBufferTranspFillChbx->setChecked( buffer.fillBufferInterior() );
   comboBufferBlendMode->setBlendMode( buffer.blendMode() );
-
+  if ( buffer.paintEffect() )
+    mBufferEffect.reset( buffer.paintEffect()->clone() );
+  else
+  {
+    mBufferEffect.reset( QgsPaintEffectRegistry::defaultStack() );
+    mBufferEffect->setEnabled( false );
+  }
+  mBufferEffectWidget->setPaintEffect( mBufferEffect.get() );
 
   mFontSizeUnitWidget->setUnit( format.sizeUnit() );
   mFontSizeUnitWidget->setMapUnitScale( format.sizeMapUnitScale() );
@@ -735,6 +748,10 @@ QgsTextFormat QgsTextFormatWidget::format() const
   buffer.setJoinStyle( mBufferJoinStyleComboBox->penJoinStyle() );
   buffer.setFillBufferInterior( mBufferTranspFillChbx->isChecked() );
   buffer.setBlendMode( comboBufferBlendMode->blendMode() );
+  if ( mBufferEffect && !QgsPaintEffectRegistry::isDefaultStack( mBufferEffect.get() ) )
+    buffer.setPaintEffect( mBufferEffect->clone() );
+  else
+    buffer.setPaintEffect( nullptr );
   format.setBuffer( buffer );
 
   // shape background
diff --git a/src/gui/qgstextformatwidget.h b/src/gui/qgstextformatwidget.h
@@ -136,6 +136,7 @@ class GUI_EXPORT QgsTextFormatWidget : public QWidget, protected Ui::QgsTextForm
     Mode mWidgetMode;
     QgsMapCanvas *mMapCanvas = nullptr;
     QgsCharacterSelectorDialog *mCharDlg = nullptr;
+    std::unique_ptr< QgsPaintEffect > mBufferEffect;
 
     QFontDatabase mFontDB;
 
diff --git a/src/ui/qgstextformatwidgetbase.ui b/src/ui/qgstextformatwidgetbase.ui
diff --git a/tests/src/python/test_qgstextrenderer.py b/tests/src/python/test_qgstextrenderer.py
