[maptips] fix font not respecting user settings

(this is important for non-Latin users out there)

python/gui/auto_generated/qgsmaptip.sip.in

@@ -61,6 +61,11 @@ Show a maptip at a given point on the map canvas
 Clear the current maptip if it exists
 
 :param mpMapCanvas: the canvas from which the tip should be cleared.
+%End
+
+    void applyFontSettings();
+%Docstring
+Apply font family and size to match user settings
 %End
 
 };

src/app/qgisapp.cpp

@@ -2335,6 +2335,11 @@ void QgisApp::setAppStyleSheet( const QString &stylesheet )
   {
     d->setStyleSheet( stylesheet );
   }
+
+  if ( mpMaptip )
+  {
+    mpMaptip->applyFontSettings();
+  }
 }
 
 int QgisApp::messageTimeout()

src/app/qgsoptions.cpp

@@ -1634,6 +1634,8 @@ void QgsOptions::saveOptions()
   if ( mStyleSheetNewOpts != mStyleSheetOldOpts )
   {
     mStyleSheetBuilder->saveToSettings( mStyleSheetNewOpts );
+    // trigger an extra  style sheet build to propagate saved settings
+    mStyleSheetBuilder->buildStyleSheet( mStyleSheetNewOpts );
   }
 
   mDefaultDatumTransformTableWidget->transformContext().writeSettings();

src/gui/qgsmaptip.cpp

@@ -19,6 +19,7 @@
 #include "qgsvectorlayer.h"
 #include "qgsexpression.h"
 #include "qgslogger.h"
+#include "qgssettings.h"
 #include "qgswebview.h"
 #include "qgswebframe.h"
 
@@ -40,6 +41,9 @@ QgsMapTip::QgsMapTip()
 {
   // Init the visible flag
   mMapTipVisible = false;
+
+  // Init font-related values
+  applyFontSettings();
 }
 
 void QgsMapTip::showMapTip( QgsMapLayer *pLayer,
@@ -118,7 +122,8 @@ void QgsMapTip::showMapTip( QgsMapLayer *pLayer,
   bodyStyle = QString(
                 "background-color: %1;"
                 "margin: 0;"
-                "white-space: nowrap;" ).arg( backgroundColor );
+                "white-space: nowrap;"
+                "font: %2pt \"%3\";" ).arg( backgroundColor ).arg( mFontSize ).arg( mFontFamily );
 
   containerStyle = QString(
                      "display: inline-block;"
@@ -131,6 +136,8 @@ void QgsMapTip::showMapTip( QgsMapLayer *pLayer,
               "</body>"
               "</html>" ).arg( bodyStyle, containerStyle, tipText );
 
+  QgsDebugMsg( tipHtml );
+
   mWidget->move( pixelPosition.x(),
                  pixelPosition.y() );
 
@@ -216,6 +223,14 @@ QString QgsMapTip::fetchFeature( QgsMapLayer *layer, QgsPointXY &mapPosition, Qg
   return tipString;
 }
 
+void QgsMapTip::applyFontSettings()
+{
+  QgsSettings settings;
+  QFont defaultFont = qApp->font();
+  mFontSize = settings.value( QStringLiteral( "/qgis/stylesheet/fontPointSize" ), defaultFont.pointSize() ).toInt();
+  mFontFamily = settings.value( QStringLiteral( "/qgis/stylesheet/fontFamily" ), defaultFont.family() ).toString();
+}
+
 // This slot handles all clicks
 void QgsMapTip::onLinkClicked( const QUrl &url )
 {

src/gui/qgsmaptip.h

@@ -79,6 +79,11 @@ class GUI_EXPORT QgsMapTip : public QWidget
      */
     void clear( QgsMapCanvas *mpMapCanvas = nullptr );
 
+    /**
+     * Apply font family and size to match user settings
+     */
+    void applyFontSettings();
+
   private slots:
     void onLinkClicked( const QUrl &url );
     void resizeContent();
@@ -99,6 +104,9 @@ class GUI_EXPORT QgsMapTip : public QWidget
     QWidget *mWidget = nullptr;
     QgsWebView *mWebView = nullptr;
 
+    QString mFontFamily;
+    int mFontSize = 8;
+
     const int MARGIN_VALUE = 5;
 };
 #endif // QGSMAPTIP_H