Allow copying and pasting symbols between QgsSymbolButtons

python/core/symbology-ng/qgssymbol.sip

@@ -88,7 +88,7 @@ return new default symbol for specified geometry type
  :rtype: QgsSymbolLayer
 %End
 
-    int symbolLayerCount();
+    int symbolLayerCount() const;
 %Docstring
  Returns total number of symbol layers contained in the symbol.
  :return: count of symbol layers

python/core/symbology-ng/qgssymbollayer.sip

@@ -231,8 +231,10 @@ class QgsSymbolLayer
 
     virtual QgsSymbol *subSymbol();
 %Docstring
+ Returns the symbol's sub symbol, if present.
  :rtype: QgsSymbol
 %End
+
     virtual bool setSubSymbol( QgsSymbol *symbol /Transfer/ );
 %Docstring
 set layer's subsymbol. takes ownership of the passed symbol

python/core/symbology-ng/qgssymbollayerutils.sip

@@ -548,6 +548,25 @@ Writes a collection of symbols to XML with specified tagName for the top-level e
 
     static void clearSymbolMap( QgsSymbolMap &symbols );
 
+    static QMimeData *symbolToMimeData( QgsSymbol *symbol ) /Factory/;
+%Docstring
+ Creates new mime data from a ``symbol``.
+ This also sets the mime color data to match the symbol's color, so that copied symbols
+ can be paste in places where a color is expected.
+.. seealso:: symbolFromMimeData()
+.. versionadded:: 3.0
+ :rtype: QMimeData
+%End
+
+    static QgsSymbol *symbolFromMimeData( const QMimeData *data ) /Factory/;
+%Docstring
+ Attempts to parse ``mime`` data as a symbol. A new symbol instance will be returned
+ if the data was successfully converted to a symbol.
+.. seealso:: symbolToMimeData()
+.. versionadded:: 3.0
+ :rtype: QgsSymbol
+%End
+
     static QgsColorRamp *loadColorRamp( QDomElement &element ) /Factory/;
 %Docstring
  Creates a color ramp from the settings encoded in an XML element

python/gui/qgssymbolbutton.sip

@@ -32,6 +32,21 @@ class QgsSymbolButton : QToolButton
 
     virtual QSize minimumSizeHint() const;
 
+    void setSymbolType( QgsSymbol::SymbolType type );
+%Docstring
+ Sets the symbol ``type`` which the button requires.
+ If the type differs from the current symbol type, the symbol will be reset
+ to a default symbol style of the new type.
+.. seealso:: symbolType()
+%End
+
+    QgsSymbol::SymbolType symbolType() const;
+%Docstring
+ Returns the symbol type which the button requires.
+.. seealso:: setSymbolType()
+ :rtype: QgsSymbol.SymbolType
+%End
+
     void setDialogTitle( const QString &title );
 %Docstring
  Sets the ``title`` for the symbol settings dialog window.
@@ -105,6 +120,19 @@ class QgsSymbolButton : QToolButton
  to the previous symbol color.
 %End
 
+    void copySymbol();
+%Docstring
+ Copies the current symbol to the clipboard.
+.. seealso:: pasteSymbol()
+%End
+
+    void pasteSymbol();
+%Docstring
+ Pastes a symbol from the clipboard. If clipboard does not contain a valid
+ symbol then no change is applied.
+.. seealso:: copySymbol()
+%End
+
     void copyColor();
 %Docstring
  Copies the current symbol color to the clipboard.

src/app/composer/qgscomposershapewidget.cpp

@@ -45,6 +45,8 @@ QgsComposerShapeWidget::QgsComposerShapeWidget( QgsComposerShape *composerShape
   mShapeComboBox->addItem( tr( "Rectangle" ) );
   mShapeComboBox->addItem( tr( "Triangle" ) );
 
+  mShapeStyleButton->setSymbolType( QgsSymbol::Fill );
+
   setGuiElementValues();
 
   blockAllSignals( false );

src/app/qgsannotationwidget.cpp

@@ -33,6 +33,9 @@ QgsAnnotationWidget::QgsAnnotationWidget( QgsMapCanvasAnnotationItem *item, QWid
   setupUi( this );
   mLayerComboBox->setAllowEmptyLayer( true );
 
+  mMapMarkerButton->setSymbolType( QgsSymbol::Marker );
+  mFrameStyleButton->setSymbolType( QgsSymbol::Fill );
+
   if ( mItem && mItem->annotation() )
   {
     QgsAnnotation *annotation = mItem->annotation();

src/app/qgsdecorationgriddialog.cpp

@@ -34,6 +34,9 @@ QgsDecorationGridDialog::QgsDecorationGridDialog( QgsDecorationGrid &deco, QWidg
 {
   setupUi( this );
 
+  mMarkerSymbolButton->setSymbolType( QgsSymbol::Marker );
+  mLineSymbolButton->setSymbolType( QgsSymbol::Line );
+
   mAnnotationFontButton->setMode( QgsFontButton::ModeQFont );
 
   QgsSettings settings;
@@ -65,6 +68,7 @@ QgsDecorationGridDialog::QgsDecorationGridDialog( QgsDecorationGrid &deco, QWidg
   connect( mAnnotationFontButton, &QgsFontButton::changed, this, &QgsDecorationGridDialog::annotationFontChanged );
 
   mMarkerSymbolButton->setMapCanvas( QgisApp::instance()->mapCanvas() );
+  mLineSymbolButton->setMapCanvas( QgisApp::instance()->mapCanvas() );
 }
 
 void QgsDecorationGridDialog::updateGuiElements()

src/app/qgsdecorationlayoutextentdialog.cpp

@@ -35,6 +35,8 @@ QgsDecorationLayoutExtentDialog::QgsDecorationLayoutExtentDialog( QgsDecorationL
 {
   setupUi( this );
 
+  mSymbolButton->setSymbolType( QgsSymbol::Fill );
+
   QgsSettings settings;
   restoreGeometry( settings.value( "/Windows/DecorationLayoutExtent/geometry" ).toByteArray() );
 

src/core/symbology-ng/qgssymbol.h

@@ -136,7 +136,7 @@ class CORE_EXPORT QgsSymbol
      * \see symbolLayers
      * \see symbolLayer
      */
-    int symbolLayerCount() { return mLayers.count(); }
+    int symbolLayerCount() const { return mLayers.count(); }
 
     /**
      * Insert symbol layer to specified index

src/core/symbology-ng/qgssymbollayer.h

@@ -252,7 +252,11 @@ class CORE_EXPORT QgsSymbolLayer
 
     virtual void drawPreviewIcon( QgsSymbolRenderContext &context, QSize size ) = 0;
 
+    /**
+     * Returns the symbol's sub symbol, if present.
+     */
     virtual QgsSymbol *subSymbol() { return nullptr; }
+
     //! set layer's subsymbol. takes ownership of the passed symbol
     virtual bool setSubSymbol( QgsSymbol *symbol SIP_TRANSFER ) { delete symbol; return false; }
 

src/core/symbology-ng/qgssymbollayerutils.cpp

@@ -2809,6 +2809,48 @@ void QgsSymbolLayerUtils::clearSymbolMap( QgsSymbolMap &symbols )
   symbols.clear();
 }
 
+QMimeData *QgsSymbolLayerUtils::symbolToMimeData( QgsSymbol *symbol )
+{
+  if ( !symbol )
+    return nullptr;
+
+  std::unique_ptr< QMimeData >mimeData( new QMimeData );
+
+  QDomDocument symbolDoc;
+  QDomElement symbolElem = saveSymbol( QStringLiteral( "symbol" ), symbol, symbolDoc, QgsReadWriteContext() );
+  symbolDoc.appendChild( symbolElem );
+  mimeData->setText( symbolDoc.toString() );
+
+  mimeData->setImageData( symbolPreviewPixmap( symbol, QSize( 100, 100 ), 18 ).toImage() );
+  mimeData->setColorData( symbol->color() );
+
+  return mimeData.release();
+}
+
+QgsSymbol *QgsSymbolLayerUtils::symbolFromMimeData( const QMimeData *data )
+{
+  if ( !data )
+    return nullptr;
+
+  QString text = data->text();
+  if ( !text.isEmpty() )
+  {
+    QDomDocument doc;
+    QDomElement elem;
+
+    if ( doc.setContent( text ) )
+    {
+      elem = doc.documentElement();
+
+      if ( elem.nodeName() != QStringLiteral( "symbol" ) )
+        elem = elem.firstChildElement( QStringLiteral( "symbol" ) );
+
+      return loadSymbol( elem, QgsReadWriteContext() );
+    }
+  }
+  return nullptr;
+}
+
 
 QgsColorRamp *QgsSymbolLayerUtils::loadColorRamp( QDomElement &element )
 {

src/core/symbology-ng/qgssymbollayerutils.h

@@ -365,6 +365,23 @@ class CORE_EXPORT QgsSymbolLayerUtils
 
     static void clearSymbolMap( QgsSymbolMap &symbols );
 
+    /**
+     * Creates new mime data from a \a symbol.
+     * This also sets the mime color data to match the symbol's color, so that copied symbols
+     * can be paste in places where a color is expected.
+     * \see symbolFromMimeData()
+     * \since QGIS 3.0
+     */
+    static QMimeData *symbolToMimeData( QgsSymbol *symbol ) SIP_FACTORY;
+
+    /**
+     * Attempts to parse \a mime data as a symbol. A new symbol instance will be returned
+     * if the data was successfully converted to a symbol.
+     * \see symbolToMimeData()
+     * \since QGIS 3.0
+     */
+    static QgsSymbol *symbolFromMimeData( const QMimeData *data ) SIP_FACTORY;
+
     /** Creates a color ramp from the settings encoded in an XML element
      * \param element DOM element
      * \returns new color ramp. Caller takes responsibility for deleting the returned value.

src/gui/attributetable/qgsfieldconditionalformatwidget.cpp

@@ -47,6 +47,7 @@ QgsFieldConditionalFormatWidget::QgsFieldConditionalFormatWidget( QWidget *paren
   mModel = new QStandardItemModel( listView );
   listView->setModel( mModel );
   mPresetsList->setModel( mPresetsModel );
+  btnChangeIcon->setSymbolType( QgsSymbol::Marker );
   btnChangeIcon->setSymbol( QgsSymbol::defaultSymbol( QgsWkbTypes::PointGeometry ) );
 
   setPresets( defaultPresets() );

src/gui/qgssymbolbutton.cpp

@@ -52,6 +52,29 @@ QSize QgsSymbolButton::minimumSizeHint() const
   return QSize( size.width(), qMax( size.height(), fontHeight ) );
 }
 
+void QgsSymbolButton::setSymbolType( QgsSymbol::SymbolType type )
+{
+  if ( type != mType )
+  {
+    switch ( type )
+    {
+      case QgsSymbol::Marker:
+        mSymbol.reset( QgsMarkerSymbol::createSimple( QgsStringMap() ) );
+        break;
+
+      case QgsSymbol::Line:
+        mSymbol.reset( QgsLineSymbol::createSimple( QgsStringMap() ) );
+        break;
+
+      case QgsSymbol::Fill:
+        mSymbol.reset( QgsFillSymbol::createSimple( QgsStringMap() ) );
+        break;
+    }
+  }
+  updatePreview();
+  mType = type;
+}
+
 void QgsSymbolButton::showSettingsDialog()
 {
   QgsExpressionContext context;
@@ -155,6 +178,18 @@ void QgsSymbolButton::setColor( const QColor &color )
   emit changed();
 }
 
+void QgsSymbolButton::copySymbol()
+{
+  QApplication::clipboard()->setMimeData( QgsSymbolLayerUtils::symbolToMimeData( mSymbol.get() ) );
+}
+
+void QgsSymbolButton::pasteSymbol()
+{
+  std::unique_ptr< QgsSymbol > symbol( QgsSymbolLayerUtils::symbolFromMimeData( QApplication::clipboard()->mimeData() ) );
+  if ( symbol && symbol->type() == mType )
+    setSymbol( symbol.release() );
+}
+
 void QgsSymbolButton::copyColor()
 {
   QApplication::clipboard()->setMimeData( QgsSymbolLayerUtils::colorToMimeData( mSymbol->color() ) );
@@ -265,6 +300,24 @@ void QgsSymbolButton::prepareMenu()
   mMenu->addAction( configureAction );
   connect( configureAction, &QAction::triggered, this, &QgsSymbolButton::showSettingsDialog );
 
+  QAction *copySymbolAction = new QAction( tr( "Copy symbol" ), this );
+  mMenu->addAction( copySymbolAction );
+  connect( copySymbolAction, &QAction::triggered, this, &QgsSymbolButton::copySymbol );
+  QAction *pasteSymbolAction = new QAction( tr( "Paste symbol" ), this );
+  //enable or disable paste action based on current clipboard contents. We always show the paste
+  //action, even if it's disabled, to give hint to the user that pasting symbols is possible
+  std::unique_ptr< QgsSymbol > tempSymbol( QgsSymbolLayerUtils::symbolFromMimeData( QApplication::clipboard()->mimeData() ) );
+  if ( tempSymbol && tempSymbol->type() == mType )
+  {
+    pasteSymbolAction->setIcon( QgsSymbolLayerUtils::symbolPreviewIcon( tempSymbol.get(), QSize( 16, 16 ), 1 ) );
+  }
+  else
+  {
+    pasteSymbolAction->setEnabled( false );
+  }
+  mMenu->addAction( pasteSymbolAction );
+  connect( pasteSymbolAction, &QAction::triggered, this, &QgsSymbolButton::pasteSymbol );
+
   mMenu->addSeparator();
 
   QgsColorWheel *colorWheel = new QgsColorWheel( mMenu );

src/gui/qgssymbolbutton.h

@@ -53,6 +53,20 @@ class GUI_EXPORT QgsSymbolButton : public QToolButton
 
     virtual QSize minimumSizeHint() const override;
 
+    /**
+     * Sets the symbol \a type which the button requires.
+     * If the type differs from the current symbol type, the symbol will be reset
+     * to a default symbol style of the new type.
+     * \see symbolType()
+     */
+    void setSymbolType( QgsSymbol::SymbolType type );
+
+    /**
+     * Returns the symbol type which the button requires.
+     * \see setSymbolType()
+     */
+    QgsSymbol::SymbolType symbolType() const { return mType; }
+
     /**
      * Sets the \a title for the symbol settings dialog window.
      * \see dialogTitle()
@@ -143,6 +157,18 @@ class GUI_EXPORT QgsSymbolButton : public QToolButton
      */
     void setColor( const QColor &color );
 
+    /** Copies the current symbol to the clipboard.
+     * \see pasteSymbol()
+     */
+    void copySymbol();
+
+    /**
+     * Pastes a symbol from the clipboard. If clipboard does not contain a valid
+     * symbol then no change is applied.
+     * \see copySymbol()
+     */
+    void pasteSymbol();
+
     /**
      * Copies the current symbol color to the clipboard.
      * \see pasteColor()
@@ -200,6 +226,8 @@ class GUI_EXPORT QgsSymbolButton : public QToolButton
 
     QString mDialogTitle;
 
+    QgsSymbol::SymbolType mType = QgsSymbol::Fill;
+
     QgsMapCanvas *mMapCanvas = nullptr;
 
     QPoint mDragStartPosition;

src/gui/symbology-ng/qgspointclusterrendererwidget.cpp

@@ -53,6 +53,8 @@ QgsPointClusterRendererWidget::QgsPointClusterRendererWidget( QgsVectorLayer *la
   mDistanceUnitWidget->setUnits( QgsUnitTypes::RenderUnitList() << QgsUnitTypes::RenderMillimeters << QgsUnitTypes::RenderMapUnits << QgsUnitTypes::RenderPixels
                                  << QgsUnitTypes::RenderPoints << QgsUnitTypes::RenderInches );
 
+  mCenterSymbolToolButton->setSymbolType( QgsSymbol::Marker );
+
   if ( renderer )
   {
     mRenderer = QgsPointClusterRenderer::convertFromRenderer( renderer );

src/gui/symbology-ng/qgspointdisplacementrendererwidget.cpp

@@ -53,6 +53,7 @@ QgsPointDisplacementRendererWidget::QgsPointDisplacementRendererWidget( QgsVecto
   mLabelFontButton->setMode( QgsFontButton::ModeQFont );
   mDistanceUnitWidget->setUnits( QgsUnitTypes::RenderUnitList() << QgsUnitTypes::RenderMillimeters << QgsUnitTypes::RenderMetersInMapUnits << QgsUnitTypes::RenderMapUnits << QgsUnitTypes::RenderPixels
                                  << QgsUnitTypes::RenderPoints << QgsUnitTypes::RenderInches );
+  mCenterSymbolToolButton->setSymbolType( QgsSymbol::Marker );
 
   if ( renderer )
   {

tests/src/python/test_qgssymbolbutton.py

@@ -14,7 +14,7 @@ __revision__ = '$Format:%H$'
 
 import qgis  # NOQA
 
-from qgis.core import QgsFillSymbol, QgsMarkerSymbol
+from qgis.core import QgsFillSymbol, QgsMarkerSymbol, QgsSymbol
 from qgis.gui import QgsSymbolButton, QgsMapCanvas
 from qgis.testing import start_app, unittest
 from qgis.PyQt.QtGui import QColor, QFont
@@ -36,6 +36,50 @@ class TestQgsSymbolButton(unittest.TestCase):
         button.setMapCanvas(canvas)
         self.assertEqual(button.mapCanvas(), canvas)
 
+        button.setSymbolType(QgsSymbol.Line)
+        self.assertEqual(button.symbolType(), QgsSymbol.Line)
+
+    def testSettingSymbolType(self)
+        button = QgsSymbolButton()
+        button.setSymbolType(QgsSymbol.Marker)
+        symbol = QgsMarkerSymbol.createSimple({})
+        symbol.setColor(QColor(255, 0, 0))
+        button.setSymbol(symbol)
+
+        # if same symbol type, existing symbol should be kept
+        button.setSymbolType(QgsSymbol.Marker)
+        self.assertEqual(button.symbol(), symbol)
+
+        # if setting different symbol type, symbol should be reset to new type
+        button.setSymbolType(QgsSymbol.Fill)
+        self.assertTrue(isinstance(button.symbol(), QgsFillSymbol))
+
+    def testPasteSymbol(self):
+        button = QgsSymbolButton()
+        button.setSymbolType(QgsSymbol.Marker)
+        symbol = QgsMarkerSymbol.createSimple({})
+        symbol.setColor(QColor(255, 0, 0))
+        button.setSymbol(symbol)
+
+        button2 = QgsSymbolButton()
+        button2.setSymbolType(QgsSymbol.Marker)
+        symbol2 = QgsMarkerSymbol.createSimple({})
+        symbol2.setColor(QColor(0, 255, 0))
+        button2.setSymbol(symbol2)
+
+        button.copySymbol()
+        button2.pasteSymbol()
+        self.assertEqual(button2.symbol().color(), QColor(255, 0, 0))
+
+        # try pasting incompatible symbol
+        button2.setSymbolType(QgsSymbol.Fill)
+        fill_symbol = QgsFillSymbol.createSimple({})
+        fill_symbol.setColor(QColor(0,0,255))
+        button2.setSymbol(fill_symbol)
+        button.copySymbol() # copied a marker symbol
+        button2.pasteSymbol() # should have no effect
+        self.assertEqual(button2.symbol(), fill_symbol)
+
     def testSetGetSymbol(self):
         button = QgsSymbolButton()
         symbol = QgsMarkerSymbol.createSimple({})

tests/src/python/test_qgssymbollayerutils.py

@@ -14,7 +14,7 @@ __revision__ = '$Format:%H$'
 
 import qgis  # NOQA
 
-from qgis.core import QgsSymbolLayerUtils
+from qgis.core import QgsSymbolLayerUtils, QgsMarkerSymbol
 from qgis.PyQt.QtCore import QSizeF, QPointF
 from qgis.testing import unittest
 
@@ -49,6 +49,20 @@ class PyQgsSymbolLayerUtils(unittest.TestCase):
         s2 = QgsSymbolLayerUtils.decodePoint('')
         self.assertEqual(s2, QPointF())
 
+    def testSymbolToFromMimeData(self):
+        """
+        Test converting symbols to and from mime data
+        """
+        symbol = QgsMarkerSymbol.createSimple({})
+        symbol.setColor(QColor(255, 0, 255))
+        self.assertFalse(QgsSymbolLayerUtils.symbolFromMimeData(None))
+        self.assertFalse(QgsSymbolLayerUtils.symbolToMimeData(None))
+        mime = QgsSymbolLayerUtils.symbolToMimeData(symbol)
+        self.assertTrue(mime is not None)
+        symbol2 = QgsSymbolLayerUtils.symbolFromMimeData(mime)
+        self.assertTrue(symbol2 is not None)
+        self.assertEqual(symbol2.color().name(), symbol.color().name())
+
 
 if __name__ == '__main__':
     unittest.main()