[fonts] Insure that text formats written to XML will save the loaded …

…family name on system missing the font family unless the font has been changed

src/core/textrenderer/qgstextformat.cpp

@@ -214,6 +214,7 @@ void QgsTextFormat::setFont( const QFont &font )
 {
   d->isValid = true;
   d->textFont = font;
+  d->originalFontFamily.clear();
 }
 
 QString QgsTextFormat::namedStyle() const
@@ -466,7 +467,8 @@ void QgsTextFormat::readFromLayer( QgsVectorLayer *layer )
 {
   d->isValid = true;
   QFont appFont = QApplication::font();
-  mTextFontFamily = QgsApplication::fontManager()->processFontFamilyName( layer->customProperty( QStringLiteral( "labeling/fontFamily" ), QVariant( appFont.family() ) ).toString() );
+  d->originalFontFamily = QgsApplication::fontManager()->processFontFamilyName( layer->customProperty( QStringLiteral( "labeling/fontFamily" ), QVariant( appFont.family() ) ).toString() );
+  mTextFontFamily = d->originalFontFamily;
   QString fontFamily = mTextFontFamily;
   if ( mTextFontFamily != appFont.family() && !QgsFontUtils::fontFamilyMatchOnSystem( mTextFontFamily ) )
   {
@@ -555,7 +557,8 @@ void QgsTextFormat::readXml( const QDomElement &elem, const QgsReadWriteContext
   else
     textStyleElem = elem.firstChildElement( QStringLiteral( "text-style" ) );
   QFont appFont = QApplication::font();
-  mTextFontFamily = QgsApplication::fontManager()->processFontFamilyName( textStyleElem.attribute( QStringLiteral( "fontFamily" ), appFont.family() ) );
+  d->originalFontFamily = QgsApplication::fontManager()->processFontFamilyName( textStyleElem.attribute( QStringLiteral( "fontFamily" ), appFont.family() ) );
+  mTextFontFamily = d->originalFontFamily;
   QString fontFamily = mTextFontFamily;
 
   const QDomElement familiesElem = textStyleElem.firstChildElement( QStringLiteral( "families" ) );
@@ -749,7 +752,7 @@ QDomElement QgsTextFormat::writeXml( QDomDocument &doc, const QgsReadWriteContex
 {
   // text style
   QDomElement textStyleElem = doc.createElement( QStringLiteral( "text-style" ) );
-  textStyleElem.setAttribute( QStringLiteral( "fontFamily" ), d->textFont.family() );
+  textStyleElem.setAttribute( QStringLiteral( "fontFamily" ), !d->originalFontFamily.isEmpty() ? d->originalFontFamily : d->textFont.family() );
 
   QDomElement familiesElem = doc.createElement( QStringLiteral( "families" ) );
   for ( const QString &family : std::as_const( d->families ) )

src/core/textrenderer/qgstextrenderer_p.h

@@ -264,6 +264,7 @@ class QgsTextSettingsPrivate : public QSharedData
     QgsTextSettingsPrivate( const QgsTextSettingsPrivate &other )
       : QSharedData( other )
       , isValid( other.isValid )
+      , originalFontFamily( other.originalFontFamily )
       , textFont( other.textFont )
       , families( other.families )
       , textNamedStyle( other.textNamedStyle )
@@ -289,6 +290,8 @@ class QgsTextSettingsPrivate : public QSharedData
     }
 
     bool isValid = false;
+
+    QString originalFontFamily;
     QFont textFont;
     QStringList families;
     QString textNamedStyle;

tests/src/python/CMakeLists.txt

@@ -520,6 +520,7 @@ if (WITH_GUI)
   ADD_PYTHON_TEST(PyQgsSymbolButton test_qgssymbolbutton.py)
   ADD_PYTHON_TEST(PyQgsTabWidget test_qgstabwidget.py)
   ADD_PYTHON_TEST(PyQgsTextFormatWidget test_qgstextformatwidget.py)
+  ADD_PYTHON_TEST(PyQgsTextFormat test_qgstextformat.py)
   ADD_PYTHON_TEST(PyQgsTreeWidgetItem test_qgstreewidgetitem.py)
   ADD_PYTHON_TEST(PyQgsValidityResultsWidget test_qgsvalidityresultswidget.py)
   ADD_PYTHON_TEST(PyQgsVectorLayer test_qgsvectorlayer.py)

tests/src/python/test_qgstextformat.py

@@ -0,0 +1,55 @@
+"""QGIS Unit tests for QgsTextFormat.
+
+.. note:: This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+"""
+__author__ = 'Mathieu Pellerin'
+__date__ = '2024-10-20'
+__copyright__ = 'Copyright 2024, The QGIS Project'
+
+from qgis.PyQt.QtGui import QFont
+from qgis.PyQt.QtXml import (
+    QDomDocument,
+    QDomElement,
+)
+from qgis.core import (
+    QgsTextFormat,
+    QgsReadWriteContext,
+)
+import unittest
+from qgis.testing import start_app, QgisTestCase
+from utilities import getTestFont
+
+start_app()
+
+
+class PyQgsTextFormat(QgisTestCase):
+
+    def testRestoringAndSavingMissingFont(self):
+        # test that a missing font on text format load will still save with the same missing font unless manually changed
+        document = QDomDocument()
+        document.setContent('<text-style fontFamily="__MISSING__" previewBkgrdColor="255,255,255,255,rgb:1,1,1,1" fieldName="" tabStopDistance="80" tabStopDistanceMapUnitScale="3x:0,0,0,0,0,0" useSubstitutions="0" forcedItalic="0" fontWeight="50" multilineHeightUnit="Percentage" allowHtml="0" fontKerning="1" multilineHeight="1" fontSizeUnit="Point" fontSize="11" blendMode="0" tabStopDistanceUnit="Point" isExpression="1" fontStrikeout="0" fontLetterSpacing="0" fontSizeMapUnitScale="3x:0,0,0,0,0,0" textColor="50,50,50,255,rgb:0.19607843137254902,0.19607843137254902,0.19607843137254902,1" legendString="Aa" textOrientation="horizontal" namedStyle="Regular" fontItalic="0" fontUnderline="0" forcedBold="0" capitalization="0" textOpacity="1" fontWordSpacing="0"><families/><substitutions/></text-style>')
+
+        context = QgsReadWriteContext()
+        text_format = QgsTextFormat()
+        text_format.readXml(document.documentElement(), context)
+
+        self.assertFalse(text_format.fontFound())
+        self.assertTrue(text_format.font().family() != "__MISSING__")
+
+        # when writign the settings to XML, the missing font family should still be there
+        element = text_format.writeXml(document, context)
+        self.assertEqual(element.attribute("fontFamily"), "__MISSING__")
+
+        font = getTestFont()
+        text_format.setFont(font)
+
+        # when writign the settings to XML, the originally missing font family should have been replaced by the new font family
+        element = text_format.writeXml(document, context)
+        self.assertEqual(element.attribute("fontFamily"), "QGIS Vera Sans")
+
+
+if __name__ == '__main__':
+    unittest.main()