Various fixes for photo editor and external resource widgets

- Clear picture when changing from a feature with a picture to
a feature with no picture set
- Don't try to load "NULL" as a filename
- Fix calculation of widget size so that widget can collapse
its size to nothing when it doesn't have a picture set
- Avoid incorrect scaling and cropping of pictures

Author: nyalldawson

src/gui/editorwidgets/qgsphotowidgetwrapper.cpp

@@ -56,6 +56,18 @@ void QgsPhotoWidgetWrapper::selectFileName()
 
 void QgsPhotoWidgetWrapper::loadPixmap( const QString& fileName )
 {
+  if ( fileName.isEmpty() )
+  {
+#ifdef WITH_QTWEBKIT
+    if ( mWebView )
+    {
+      mWebView->setUrl( QString() );
+    }
+#endif
+    clearPicture();
+    return;
+  }
+
   QString filePath = fileName;
 
   if ( QUrl( fileName ).isRelative() )
@@ -98,6 +110,24 @@ void QgsPhotoWidgetWrapper::loadPixmap( const QString& fileName )
       mPhotoLabel->setPixmap( pm );
     }
   }
+  else
+  {
+    clearPicture();
+  }
+}
+
+void QgsPhotoWidgetWrapper::clearPicture()
+{
+  if ( mPhotoLabel )
+  {
+    mPhotoLabel->clear();
+    mPhotoLabel->setMinimumSize( QSize( 0, 0 ) );
+
+    if ( mPhotoPixmapLabel )
+      mPhotoPixmapLabel->setPixmap( QPixmap() );
+    else
+      mPhotoLabel->setPixmap( QPixmap() );
+  }
 }
 
 QVariant QgsPhotoWidgetWrapper::value() const
@@ -212,7 +242,10 @@ void QgsPhotoWidgetWrapper::setValue( const QVariant& value )
   if ( mLineEdit )
   {
     if ( value.isNull() )
-      mLineEdit->setText( QSettings().value( "qgis/nullValue", "NULL" ).toString() );
+    {
+      whileBlocking( mLineEdit )->setText( QSettings().value( "qgis/nullValue", "NULL" ).toString() );
+      clearPicture();
+    }
     else
       mLineEdit->setText( value.toString() );
   }

src/gui/editorwidgets/qgsphotowidgetwrapper.h

@@ -78,6 +78,8 @@ class GUI_EXPORT QgsPhotoWidgetWrapper : public QgsEditorWidgetWrapper
     QLineEdit* mLineEdit;
     //! The button to open the file chooser dialog
     QPushButton* mButton;
+
+    void clearPicture();
 };
 
 #endif // QGSPHOTOWIDGETWRAPPER_H

src/gui/qgsexternalresourcewidget.cpp

@@ -142,7 +142,11 @@ void QgsExternalResourceWidget::updateDocumentViewer()
   {
     const QPixmap* pm = mPixmapLabel->pixmap();
 
-    if ( pm )
+    if ( !pm || pm->isNull() )
+    {
+      mPixmapLabel->setMinimumSize( QSize( 0, 0 ) );
+    }
+    else
     {
       QSize size( mDocumentViewerWidth, mDocumentViewerHeight );
       if ( size.width() == 0 && size.height() > 0 )
@@ -165,7 +169,7 @@ void QgsExternalResourceWidget::updateDocumentViewer()
 
 void QgsExternalResourceWidget::loadDocument( const QString& path )
 {
-  if ( path.isNull() )
+  if ( path.isEmpty() )
   {
 #ifdef WITH_QTWEBKIT
     if ( mDocumentViewerContent == Web )
@@ -176,6 +180,7 @@ void QgsExternalResourceWidget::loadDocument( const QString& path )
     if ( mDocumentViewerContent == Image )
     {
       mPixmapLabel->clear();
+      updateDocumentViewer();
     }
   }
 
@@ -190,12 +195,8 @@ void QgsExternalResourceWidget::loadDocument( const QString& path )
   if ( mDocumentViewerContent == Image )
   {
     QPixmap pm( path );
-    if ( !pm.isNull() )
-    {
-      mPixmapLabel->setPixmap( pm );
-
-      updateDocumentViewer();
-    }
+    mPixmapLabel->setPixmap( pm );
+    updateDocumentViewer();
   }
 }
 

src/gui/qgspixmaplabel.cpp

@@ -24,17 +24,31 @@ QgsPixmapLabel::QgsPixmapLabel( QWidget *parent ) :
 
 void QgsPixmapLabel::setPixmap( const QPixmap & p )
 {
+  bool sizeChanged = ( p.size() != mPixmap.size() );
   mPixmap = p;
-  QLabel::setPixmap( p );
+
+  if ( sizeChanged )
+  {
+    updateGeometry();
+  }
+
+  QLabel::setPixmap( mPixmap.scaled( this->size(),
+                                     Qt::KeepAspectRatio, Qt::SmoothTransformation ) );
 }
 
 int QgsPixmapLabel::heightForWidth( int width ) const
 {
+  if ( mPixmap.isNull() )
+    return 0;
+
   return (( qreal )mPixmap.height()*width ) / mPixmap.width();
 }
 
 QSize QgsPixmapLabel::sizeHint() const
 {
+  if ( mPixmap.isNull() )
+    return QSize( 0, 0 );
+
   int w = this->width();
   return QSize( w, heightForWidth( w ) );
 }