Add support for rendering using QgsLegendPatchShape to QgsSymbol::dra…

…wPreviewIcon
qgis · Apr 10, 2020 · 40638fe · 40638fe
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commit 40638fe
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Showing 13 changed files with 217 additions and 44 deletions.
diff --git a/python/core/auto_generated/symbology/qgssymbol.sip.in b/python/core/auto_generated/symbology/qgssymbol.sip.in
@@ -272,7 +272,8 @@ layer.
 .. seealso:: :py:func:`setColor`
 %End
 
-    void drawPreviewIcon( QPainter *painter, QSize size, QgsRenderContext *customContext = 0, bool selected = false, const QgsExpressionContext *expressionContext = 0 );
+    void drawPreviewIcon( QPainter *painter, QSize size, QgsRenderContext *customContext = 0, bool selected = false, const QgsExpressionContext *expressionContext = 0,
+                          const QgsLegendPatchShape *patchShape = 0 );
 %Docstring
 Draws an icon of the symbol that occupies an area given by ``size`` using the specified ``painter``.
 
@@ -284,6 +285,7 @@ matches the settings from that context.
 :param customContext: the context in which the rendering happens
 :param selected: set to ``True`` to render the symbol in a selected state
 :param expressionContext: optional custom expression context
+:param patchShape: optional patch shape to use for symbol preview. If not specified a default shape will be used instead.
 
 .. seealso:: :py:func:`exportImage`
 
@@ -613,6 +615,8 @@ Constructor for QgsSymbolRenderContext
 :param mapUnitScale:
 %End
 
+    ~QgsSymbolRenderContext();
+
 
     QgsRenderContext &renderContext();
 %Docstring
@@ -800,6 +804,24 @@ Set an expression scope for this symbol.
 Will take ownership.
 
 :param contextScope: An expression scope for details about this symbol
+%End
+
+    const QgsLegendPatchShape *patchShape() const;
+%Docstring
+Returns the symbol patch shape, to use if rendering symbol preview icons.
+
+.. seealso:: :py:func:`setPatchShape`
+
+.. versionadded:: 3.14
+%End
+
+    void setPatchShape( const QgsLegendPatchShape &shape );
+%Docstring
+Sets the symbol patch ``shape``, to use if rendering symbol preview icons.
+
+.. seealso:: :py:func:`patchShape`
+
+.. versionadded:: 3.14
 %End
 
   private:

diff --git a/src/core/symbology/qgsgeometrygeneratorsymbollayer.cpp b/src/core/symbology/qgsgeometrygeneratorsymbollayer.cpp
@@ -137,7 +137,7 @@ QgsStringMap QgsGeometryGeneratorSymbolLayer::properties() const
 void QgsGeometryGeneratorSymbolLayer::drawPreviewIcon( QgsSymbolRenderContext &context, QSize size )
 {
   if ( mSymbol )
-    mSymbol->drawPreviewIcon( context.renderContext().painter(), size );
+    mSymbol->drawPreviewIcon( context.renderContext().painter(), size, nullptr, false, nullptr, context.patchShape() );
 }
 
 void QgsGeometryGeneratorSymbolLayer::setGeometryExpression( const QString &exp )

diff --git a/src/core/symbology/qgssymbol.cpp b/src/core/symbology/qgssymbol.cpp
@@ -50,6 +50,7 @@
 #include "qgsapplication.h"
 #include "qgsexpressioncontextutils.h"
 #include "qgsrenderedfeaturehandlerinterface.h"
+#include "qgslegendpatchshape.h"
 
 inline
 QgsProperty rotateWholeSymbol( double additionalRotation, const QgsProperty &property )
@@ -499,7 +500,7 @@ QColor QgsSymbol::color() const
   return QColor( 0, 0, 0 );
 }
 
-void QgsSymbol::drawPreviewIcon( QPainter *painter, QSize size, QgsRenderContext *customContext, bool selected, const QgsExpressionContext *expressionContext )
+void QgsSymbol::drawPreviewIcon( QPainter *painter, QSize size, QgsRenderContext *customContext, bool selected, const QgsExpressionContext *expressionContext, const QgsLegendPatchShape *patchShape )
 {
   QgsRenderContext *context = customContext;
   std::unique_ptr< QgsRenderContext > tempContext;
@@ -514,6 +515,8 @@ void QgsSymbol::drawPreviewIcon( QPainter *painter, QSize size, QgsRenderContext
   QgsSymbolRenderContext symbolContext( *context, QgsUnitTypes::RenderUnknownUnit, mOpacity, false, mRenderHints, nullptr );
   symbolContext.setSelected( selected );
   symbolContext.setOriginalGeometryType( mType == Fill ? QgsWkbTypes::PolygonGeometry : QgsWkbTypes::UnknownGeometry );
+  if ( patchShape )
+    symbolContext.setPatchShape( *patchShape );
 
   if ( !customContext && expressionContext )
   {
@@ -539,19 +542,31 @@ void QgsSymbol::drawPreviewIcon( QPainter *painter, QSize size, QgsRenderContext
       QgsLineSymbolLayer *lsl = dynamic_cast<QgsLineSymbolLayer *>( layer );
       if ( lsl )
       {
-        // from QgsFillSymbolLayer::drawPreviewIcon()
-        QPolygonF poly = QRectF( QPointF( 0, 0 ), QPointF( size.width() - 1, size.height() - 1 ) );
+        // from QgsFillSymbolLayer::drawPreviewIcon() -- would be nicer to add the
+        // symbol type to QgsSymbolLayer::drawPreviewIcon so this logic could be avoided!
+
+        // hmm... why was this using size -1 ??
+        const QSizeF targetSize = QSizeF( size.width() - 1, size.height() - 1 );
+
+        const QList< QList< QPolygonF > > polys = patchShape ? patchShape->toQPolygonF( QgsSymbol::Fill, targetSize )
+            : QgsLegendPatchShape::defaultPatch( QgsSymbol::Fill, targetSize );
+
         lsl->startRender( symbolContext );
         QgsPaintEffect *effect = lsl->paintEffect();
+
+        std::unique_ptr< QgsEffectPainter > effectPainter;
         if ( effect && effect->enabled() )
+          effectPainter = qgis::make_unique< QgsEffectPainter >( symbolContext.renderContext(), effect );
+
+        for ( const QList< QPolygonF > &poly : polys )
         {
-          QgsEffectPainter p( symbolContext.renderContext(), effect );
-          lsl->renderPolygonStroke( poly, nullptr, symbolContext );
-        }
-        else
-        {
-          lsl->renderPolygonStroke( poly, nullptr, symbolContext );
+          QList< QPolygonF > rings;
+          for ( int i = 1; i < poly.size(); ++i )
+            rings << poly.at( i );
+          lsl->renderPolygonStroke( poly.value( 0 ), &rings, symbolContext );
         }
+
+        effectPainter.reset();
         lsl->stopRender( symbolContext );
       }
     }
@@ -1248,6 +1263,8 @@ QgsSymbolRenderContext::QgsSymbolRenderContext( QgsRenderContext &c, QgsUnitType
 {
 }
 
+QgsSymbolRenderContext::~QgsSymbolRenderContext() = default;
+
 void QgsSymbolRenderContext::setOriginalValueVariable( const QVariant &value )
 {
   mRenderContext.expressionContext().setOriginalValueVariable( value );
@@ -1283,6 +1300,16 @@ void QgsSymbolRenderContext::setExpressionContextScope( QgsExpressionContextScop
   mExpressionContextScope.reset( contextScope );
 }
 
+const QgsLegendPatchShape *QgsSymbolRenderContext::patchShape() const
+{
+  return mPatchShape.get();
+}
+
+void QgsSymbolRenderContext::setPatchShape( const QgsLegendPatchShape &patchShape )
+{
+  mPatchShape.reset( new QgsLegendPatchShape( patchShape ) );
+}
+
 ///////////////////
 
 QgsMarkerSymbol *QgsMarkerSymbol::createSimple( const QgsStringMap &properties )

diff --git a/src/core/symbology/qgssymbol.h b/src/core/symbology/qgssymbol.h
@@ -50,6 +50,7 @@ class QgsCurve;
 class QgsPolygon;
 class QgsExpressionContext;
 class QgsPoint;
+class QgsLegendPatchShape;
 
 typedef QList<QgsSymbolLayer *> QgsSymbolLayerList;
 
@@ -336,13 +337,15 @@ class CORE_EXPORT QgsSymbol
      * \param customContext the context in which the rendering happens
      * \param selected set to TRUE to render the symbol in a selected state
      * \param expressionContext optional custom expression context
+     * \param patchShape optional patch shape to use for symbol preview. If not specified a default shape will be used instead.
      *
      * \see exportImage()
      * \see asImage()
      * \note Parameter selected added in QGIS 3.10
      * \since QGIS 2.6
      */
-    void drawPreviewIcon( QPainter *painter, QSize size, QgsRenderContext *customContext = nullptr, bool selected = false, const QgsExpressionContext *expressionContext = nullptr );
+    void drawPreviewIcon( QPainter *painter, QSize size, QgsRenderContext *customContext = nullptr, bool selected = false, const QgsExpressionContext *expressionContext = nullptr,
+                          const QgsLegendPatchShape *patchShape = nullptr );
 
     /**
      * Export the symbol as an image format, to the specified \a path and with the given \a size.
@@ -694,6 +697,8 @@ class CORE_EXPORT QgsSymbolRenderContext
      */
     QgsSymbolRenderContext( QgsRenderContext &c, QgsUnitTypes::RenderUnit u, qreal opacity = 1.0, bool selected = false, QgsSymbol::RenderHints renderHints = nullptr, const QgsFeature *f = nullptr, const QgsFields &fields = QgsFields(), const QgsMapUnitScale &mapUnitScale = QgsMapUnitScale() );
 
+    ~QgsSymbolRenderContext();
+
     //! QgsSymbolRenderContext cannot be copied.
     QgsSymbolRenderContext( const QgsSymbolRenderContext &rh ) = delete;
 
@@ -861,6 +866,22 @@ class CORE_EXPORT QgsSymbolRenderContext
      */
     void setExpressionContextScope( QgsExpressionContextScope *contextScope SIP_TRANSFER );
 
+    /**
+     * Returns the symbol patch shape, to use if rendering symbol preview icons.
+     *
+     * \see setPatchShape()
+     * \since QGIS 3.14
+     */
+    const QgsLegendPatchShape *patchShape() const;
+
+    /**
+     * Sets the symbol patch \a shape, to use if rendering symbol preview icons.
+     *
+     * \see patchShape()
+     * \since QGIS 3.14
+     */
+    void setPatchShape( const QgsLegendPatchShape &shape );
+
   private:
 
 #ifdef SIP_RUN
@@ -879,6 +900,7 @@ class CORE_EXPORT QgsSymbolRenderContext
     int mGeometryPartCount;
     int mGeometryPartNum;
     QgsWkbTypes::GeometryType mOriginalGeometryType = QgsWkbTypes::UnknownGeometry;
+    std::unique_ptr< QgsLegendPatchShape > mPatchShape;
 };
 
 

diff --git a/src/core/symbology/qgssymbollayer.cpp b/src/core/symbology/qgssymbollayer.cpp
@@ -27,6 +27,8 @@
 #include "qgsexpressioncontext.h"
 #include "qgssymbollayerutils.h"
 #include "qgsapplication.h"
+#include "qgsmultipoint.h"
+#include "qgslegendpatchshape.h"
 
 #include <QSize>
 #include <QPainter>
@@ -449,15 +451,19 @@ void QgsMarkerSymbolLayer::drawPreviewIcon( QgsSymbolRenderContext &context, QSi
 {
   startRender( context );
   QgsPaintEffect *effect = paintEffect();
+
+  QPolygonF points = context.patchShape() ? context.patchShape()->toQPolygonF( QgsSymbol::Marker, size ).value( 0 ).value( 0 )
+                     : QgsLegendPatchShape::defaultPatch( QgsSymbol::Marker, size ).value( 0 ).value( 0 );
+
+  std::unique_ptr< QgsEffectPainter > effectPainter;
   if ( effect && effect->enabled() )
-  {
-    QgsEffectPainter p( context.renderContext(), effect );
-    renderPoint( QPointF( size.width() / 2, size.height() / 2 ), context );
-  }
-  else
-  {
-    renderPoint( QPointF( size.width() / 2, size.height() / 2 ), context );
-  }
+    effectPainter = qgis::make_unique< QgsEffectPainter >( context.renderContext(), effect );
+
+  for ( QPointF point : qgis::as_const( points ) )
+    renderPoint( point, context );
+
+  effectPainter.reset();
+
   stopRender( context );
 }
 
@@ -633,22 +639,20 @@ QgsMapUnitScale QgsLineSymbolLayer::mapUnitScale() const
 
 void QgsLineSymbolLayer::drawPreviewIcon( QgsSymbolRenderContext &context, QSize size )
 {
-  QPolygonF points;
-  // we're adding 0.5 to get rid of blurred preview:
-  // drawing antialiased lines of width 1 at (x,0)-(x,100) creates 2px line
-  points << QPointF( 0, int( size.height() / 2 ) + 0.5 ) << QPointF( size.width(), int( size.height() / 2 ) + 0.5 );
-
+  const QList< QList< QPolygonF > > points = context.patchShape() ? context.patchShape()->toQPolygonF( QgsSymbol::Line, size )
+      : QgsLegendPatchShape::defaultPatch( QgsSymbol::Line, size );
   startRender( context );
   QgsPaintEffect *effect = paintEffect();
+
+  std::unique_ptr< QgsEffectPainter > effectPainter;
   if ( effect && effect->enabled() )
-  {
-    QgsEffectPainter p( context.renderContext(), effect );
-    renderPolyline( points, context );
-  }
-  else
-  {
-    renderPolyline( points, context );
-  }
+    effectPainter = qgis::make_unique< QgsEffectPainter >( context.renderContext(), effect );
+
+  for ( const QList< QPolygonF > &line : points )
+    renderPolyline( line.value( 0 ), context );
+
+  effectPainter.reset();
+
   stopRender( context );
 }
 
@@ -695,18 +699,26 @@ double QgsLineSymbolLayer::dxfWidth( const QgsDxfExport &e, QgsSymbolRenderConte
 
 void QgsFillSymbolLayer::drawPreviewIcon( QgsSymbolRenderContext &context, QSize size )
 {
-  QPolygonF poly = QRectF( QPointF( 0, 0 ), QPointF( size.width(), size.height() ) );
+  const QList< QList< QPolygonF > > polys = context.patchShape() ? context.patchShape()->toQPolygonF( QgsSymbol::Fill, size )
+      : QgsLegendPatchShape::defaultPatch( QgsSymbol::Fill, size );
+
   startRender( context );
   QgsPaintEffect *effect = paintEffect();
+
+  std::unique_ptr< QgsEffectPainter > effectPainter;
   if ( effect && effect->enabled() )
+    effectPainter = qgis::make_unique< QgsEffectPainter >( context.renderContext(), effect );
+
+  for ( const QList< QPolygonF > &poly : polys )
   {
-    QgsEffectPainter p( context.renderContext(), effect );
-    renderPolygon( poly, nullptr, context );
-  }
-  else
-  {
-    renderPolygon( poly, nullptr, context );
+    QList< QPolygonF > rings;
+    for ( int i = 1; i < poly.size(); ++i )
+      rings << poly.at( i );
+    renderPolygon( poly.value( 0 ), &rings, context );
   }
+
+  effectPainter.reset();
+
   stopRender( context );
 }