Accept dropped colors on color widgets

Author: nyalldawson

python/core/symbology-ng/qgssymbollayerv2utils.sip

@@ -200,6 +200,17 @@ class QgsSymbolLayerV2Utils
      */
     static QList< QColor > parseColorList( const QString colorStr );
 
+    /**
+     * Attempts to parse mime data as a color
+     * @param data mime data to parse
+     * @param hasAlpha will be set to true if mime data was interpreted as a color containing
+     * an explicit alpha value
+     * @returns valid color if mimedata could be interpreted as a color, otherwise an
+     * invalid color
+     * @note added in 2.5
+     */
+    static QColor colorFromMimeData( const QMimeData * mimeData, bool& hasAlpha );
+    
     /**
      * Attempts to parse mime data as a list of named colors
      * @param data mime data to parse

python/gui/qgscolorwidgets.sip

@@ -127,6 +127,12 @@ class QgsColorWidget : QWidget
      */
     static const QPixmap& transparentBackground();
 
+    //Reimplemented to accept dragged colors
+    void dragEnterEvent( QDragEnterEvent * e ) ;
+
+    //Reimplemented to accept dropped colors
+    void dropEvent( QDropEvent *e );
+
 };
 
 

src/core/symbology-ng/qgssymbollayerv2utils.cpp

@@ -2799,6 +2799,28 @@ QList<QColor> QgsSymbolLayerV2Utils::parseColorList( const QString colorStr )
   return colors;
 }
 
+QColor QgsSymbolLayerV2Utils::colorFromMimeData( const QMimeData * mimeData, bool& hasAlpha )
+{
+  //attempt to read color data directly from mime
+  QColor mimeColor = mimeData->colorData().value<QColor>();
+  if ( mimeColor.isValid() )
+  {
+    hasAlpha = true;
+    return mimeColor;
+  }
+
+  //attempt to intrepret a color from mime text data
+  hasAlpha = false;
+  QColor textColor = QgsSymbolLayerV2Utils::parseColorWithAlpha( mimeData->text(), hasAlpha );
+  if ( textColor.isValid() )
+  {
+    return textColor;
+  }
+
+  //could not get color from mime data
+  return QColor();
+}
+
 QgsNamedColorList QgsSymbolLayerV2Utils::colorListFromMimeData( const QMimeData *data )
 {
   QgsNamedColorList mimeColors;

src/core/symbology-ng/qgssymbollayerv2utils.h

@@ -238,6 +238,17 @@ class CORE_EXPORT QgsSymbolLayerV2Utils
      */
     static QList< QColor > parseColorList( const QString colorStr );
 
+    /**
+     * Attempts to parse mime data as a color
+     * @param data mime data to parse
+     * @param hasAlpha will be set to true if mime data was interpreted as a color containing
+     * an explicit alpha value
+     * @returns valid color if mimedata could be interpreted as a color, otherwise an
+     * invalid color
+     * @note added in 2.5
+     */
+    static QColor colorFromMimeData( const QMimeData * mimeData, bool& hasAlpha );
+
     /**
      * Attempts to parse mime data as a list of named colors
      * @param data mime data to parse

src/gui/qgscolorbuttonv2.cpp

@@ -155,35 +155,22 @@ QMimeData * QgsColorButtonV2::createColorMimeData() const
 
 bool QgsColorButtonV2::colorFromMimeData( const QMimeData * mimeData, QColor& resultColor )
 {
-  //attempt to read color data directly from mime
-  QColor mimeColor = mimeData->colorData().value<QColor>();
+  bool hasAlpha = false;
+  QColor mimeColor = QgsSymbolLayerV2Utils::colorFromMimeData( mimeData, hasAlpha );
+
   if ( mimeColor.isValid() )
   {
     if ( !( mColorDialogOptions & QColorDialog::ShowAlphaChannel ) )
     {
       //remove alpha channel
       mimeColor.setAlpha( 255 );
     }
-    resultColor = mimeColor;
-    return true;
-  }
-
-  //attempt to intrepret a color from mime text data
-  bool hasAlpha = false;
-  QColor textColor = QgsSymbolLayerV2Utils::parseColorWithAlpha( mimeData->text(), hasAlpha );
-  if ( textColor.isValid() )
-  {
-    if ( !( mColorDialogOptions & QColorDialog::ShowAlphaChannel ) )
-    {
-      //remove alpha channel
-      textColor.setAlpha( 255 );
-    }
     else if ( !hasAlpha )
     {
       //mime color has no explicit alpha component, so keep existing alpha
-      textColor.setAlpha( mColor.alpha() );
+      mimeColor.setAlpha( mColor.alpha() );
     }
-    resultColor = textColor;
+    resultColor = mimeColor;
     return true;
   }
 

src/gui/qgscolorwidgets.cpp

@@ -38,7 +38,7 @@ QgsColorWidget::QgsColorWidget( QWidget* parent, const ColorComponent component
     , mCurrentColor( Qt::red )
     , mComponent( component )
 {
-
+  setAcceptDrops( true );
 }
 
 QgsColorWidget::~QgsColorWidget()
@@ -163,6 +163,43 @@ const QPixmap &QgsColorWidget::transparentBackground()
   return transpBkgrd;
 }
 
+void QgsColorWidget::dragEnterEvent( QDragEnterEvent *e )
+{
+  //is dragged data valid color data?
+  bool hasAlpha;
+  QColor mimeColor = QgsSymbolLayerV2Utils::colorFromMimeData( e->mimeData(), hasAlpha );
+
+  if ( mimeColor.isValid() )
+  {
+    //if so, we accept the drag
+    e->acceptProposedAction();
+  }
+}
+
+void QgsColorWidget::dropEvent( QDropEvent *e )
+{
+  //is dropped data valid color data?
+  bool hasAlpha = false;
+  QColor mimeColor = QgsSymbolLayerV2Utils::colorFromMimeData( e->mimeData(), hasAlpha );
+
+  if ( mimeColor.isValid() )
+  {
+    //accept drop and set new color
+    e->acceptProposedAction();
+
+    if ( !hasAlpha )
+    {
+      //mime color has no explicit alpha component, so keep existing alpha
+      mimeColor.setAlpha( mCurrentColor.alpha() );
+    }
+
+    setColor( mimeColor );
+    emit colorChanged( mCurrentColor );
+  }
+
+  //could not get color from mime data
+}
+
 QColor QgsColorWidget::color() const
 {
   return mCurrentColor;

src/gui/qgscolorwidgets.h

@@ -158,6 +158,12 @@ class GUI_EXPORT QgsColorWidget : public QWidget
      * @returns checkerboard pixmap
      */
     static const QPixmap& transparentBackground();
+
+    //Reimplemented to accept dragged colors
+    void dragEnterEvent( QDragEnterEvent * e ) ;
+
+    //Reimplemented to accept dropped colors
+    void dropEvent( QDropEvent *e );
 };