Update symbol selector when svg cache fetches remote images

(cherry-picked from 2e6a69b)

Author: nyalldawson

src/core/symbology/qgssvgcache.cpp

@@ -84,7 +84,7 @@ QgsSvgCache::QgsSvgCache( QObject *parent )
   , mMutex( QMutex::Recursive )
 {
   mMissingSvg = QStringLiteral( "<svg width='10' height='10'><text x='5' y='10' font-size='10' text-anchor='middle'>?</text></svg>" ).toLatin1();
-  mFetchingSvg = QStringLiteral( "<svg width='10' height='10'><text x='5' y='10' font-size='10' text-anchor='middle'>x</text></svg>" ).toLatin1();
+  mFetchingSvg = QStringLiteral( "<svg width='10' height='10'><text x='5' y='10' font-size='10' text-anchor='middle'>&#8987;</text></svg>" ).toLatin1();
 }
 
 QgsSvgCache::~QgsSvgCache()

src/gui/symbology/qgssymbolslistwidget.cpp

@@ -29,6 +29,7 @@
 #include "qgssettings.h"
 #include "qgsnewauxiliarylayerdialog.h"
 #include "qgsauxiliarystorage.h"
+#include "qgssvgcache.h"
 
 #include <QAction>
 #include <QString>
@@ -114,6 +115,13 @@ QgsSymbolsListWidget::QgsSymbolsListWidget( QgsSymbol *symbol, QgsStyle *style,
   connect( btnSaveSymbol, &QPushButton::clicked, this, &QgsSymbolsListWidget::saveSymbol );
 
   connect( mOpacityWidget, &QgsOpacityWidget::opacityChanged, this, &QgsSymbolsListWidget::opacityChanged );
+
+  // when a remote svg has been fetched, update the widget's previews
+  // this is required if the symbol utilises remote svgs, and the current previews
+  // have been generated using the temporary "downloading" svg. In this case
+  // we require the preview to be regenerated to use the correct fetched
+  // svg
+  connect( QgsApplication::svgCache(), &QgsSvgCache::remoteSvgFetched, this, &QgsSymbolsListWidget::populateSymbolView );
 }
 
 QgsSymbolsListWidget::~QgsSymbolsListWidget()

src/gui/symbology/qgssymbolslistwidget.h

@@ -104,6 +104,7 @@ class GUI_EXPORT QgsSymbolsListWidget : public QWidget, private Ui::SymbolsListW
     void updateAssistantSymbol();
     void opacityChanged( double value );
     void createAuxiliaryField();
+    void populateSymbolView();
 
   private:
     QgsSymbol *mSymbol = nullptr;
@@ -114,7 +115,6 @@ class GUI_EXPORT QgsSymbolsListWidget : public QWidget, private Ui::SymbolsListW
     QgsVectorLayer *mLayer = nullptr;
     QgsMapCanvas *mMapCanvas = nullptr;
 
-    void populateSymbolView();
     void populateSymbols( const QStringList &symbols );
     void updateSymbolColor();
     void updateSymbolInfo();