Merge #7068: feat(qt): extract Dash-specific font infrastructure to qt/guiutil_font.{cpp,h}, encapsulate globals into Font{Info,Registry}, add arbitrary font support

b6d418a fix: always use `getFontNormal()` for Montserrat on macOS (Kittywhiskers Van Gogh)
4cc4040 fix: restore font on cancel, apply font when adjusting weight (Kittywhiskers Van Gogh)
7c2f616 fix: don't rely on `QSettings` weights if `-font-family` set (Kittywhiskers Van Gogh)
d2b8c0a fix: don't display stale weight settings if `-font-family` set (Kittywhiskers Van Gogh)
3faa368 feat(qt): add arbitrary font loading support (Kittywhiskers Van Gogh)
d3d72a2 refactor: miscellaneous refactoring (Kittywhiskers Van Gogh)
cdd7b37 refactor: consolidate font attributes to struct (Kittywhiskers Van Gogh)
2f30002 fix: disable appearance widget field if overridden by command line (Kittywhiskers Van Gogh)
6c71be8 fix: respect overridden arguments, avoid font pop in appearance widget (Kittywhiskers Van Gogh)
cc0665e fix: display error if `-font-family` set to nonexistent font (Kittywhiskers Van Gogh)
1f24526 fix: reintroduce fallbacks and assertion checks to avoid regressions (Kittywhiskers Van Gogh)
e0eb254 refactor: drop `FontFamily`, identify font with string name instead (Kittywhiskers Van Gogh)
b6a5bdb refactor: reduce `updateFonts()` invocations (Kittywhiskers Van Gogh)
96f5f93 refactor: use `g_font_registry` even more more extensively (Kittywhiskers Van Gogh)
fb9fc20 refactor: use `g_font_registry` even more extensively (Kittywhiskers Van Gogh)
e5ee874 refactor: use `g_font_registry` more extensively (Kittywhiskers Van Gogh)
d25c853 refactor: encapsulate global font state (consolidate tunables) (Kittywhiskers Van Gogh)
8a93d51 refactor: encapsulate global font state (consolidate maps) (Kittywhiskers Van Gogh)
7687e01 refactor: reduce entanglement with `FontFamily` (Kittywhiskers Van Gogh)
d21ceb1 refactor: use `strprintf` for `qDebug()` messages (Kittywhiskers Van Gogh)
1f239fc refactor: consolidate weight argument maps (Kittywhiskers Van Gogh)
c17a7eb refactor: consolidate Montserrat weight and name maps (Kittywhiskers Van Gogh)
6f3b11d fix: use argument passed to lambda instead of global (Kittywhiskers Van Gogh)
9cd9d44 fix: fallback to default weight if setting incompatible with font (Kittywhiskers Van Gogh)
5d5bbff lint: add to `non-backported.txt`, apply some `clang-format` suggestions (Kittywhiskers Van Gogh)
84ae194 refactor: move Dash-specific font management to `qt/guiutil_font.{cpp,h}` (Kittywhiskers Van Gogh)

Pull request description:

  ## Additional Information

  * Dependency for dashpay/dash#6831

  * Additional fixes have been included to deal with crash cases encountered when working on [dash#6831](dashpay/dash#6831), the first fix uses fallback weights if `fontWeight{Bold,Normal}` is set to a value not supported by the font. This is possible if the values are manually edited or overridden.

    <details>

    <summary>Crash:</summary>

      ```
      dash@8cf837862c23:/src/dash$ ./src/qt/dash-qt --testnet
      QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-dash'
      Assertion failure:
        assertion: nIndex != -1
        file: qt/optionsmodel.cpp, line: 546
        function: virtual QVariant OptionsModel::data(const QModelIndex &, int) const
         0#: (0x55D83D7D9C71) stacktraces.cpp:656    - __wrap___assert_fail
         1#: (0x55D83CF4D6D4) optionsmodel.cpp:553   - OptionsModel::data(QModelIndex const&, int) const
         2#: (0x55D83E4C4608) <unknown-file>         - ???
         3#: (0x55D83E4C9068) <unknown-file>         - ???
         4#: (0x55D83E4CA06B) <unknown-file>         - ???
         5#: (0x55D83CF0CF7E) guiutil.cpp            - GUIUtil::setupAppearance(QWidget*, OptionsModel*)
         6#: (0x55D83CEDB8D9) bitcoin.cpp:436        - BitcoinApplication::initializeResult(bool, interfaces::BlockAndHeaderTipInfo)
         7#: (0x55D83CEE8DDD) qobjectdefs_impl.h:425 - QtPrivate::QSlotObject<void (BitcoinApplication::*)(bool, interfaces::BlockAndHeaderTipInfo), QtPrivate::List<bool, interfaces::BlockAndHeaderTipInfo>, void>::impl(int, QtPrivate::QSlotObjectBase*, QObject*, void**, bool*)
         8#: (0x55D83E0C288D) <unknown-file>         - ???
         9#: (0x55D83DC5DAB9) <unknown-file>         - ???
        10#: (0x55D83E2F4186) <unknown-file>         - ???
        11#: (0x55D83E2F5BAC) <unknown-file>         - ???
        12#: (0x55D83E2F6E7E) <unknown-file>         - ???
        13#: (0x55D83E0A5668) <unknown-file>         - ???
      dash-qt: qt/optionsmodel.cpp:546: virtual QVariant OptionsModel::data(const QModelIndex &, int) const: Assertion `nIndex != -1' failed.
      Aborted (core dumped)
      ```

    </details>

    The second fix uses the argument passed to the lambda `addBestDefaults` instead of a global font, this has also been flagged by CodeRabbit ([comment](dashpay/dash#6831 (comment)))

    <details>

    <summary>Crash:</summary>

      ```
      dash@8cf837862c23:/src/dash$ ./src/qt/dash-qt --testnet
      QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-dash'
      Assertion failure:
        assertion: mapWeight.count(weight)
        file: qt/guiutil_font.cpp, line: 119
        function: int GUIUtil::weightToArg(const QFont::Weight)
         0#: (0x55B3C209CC31) stacktraces.cpp:656       - __wrap___assert_fail
         1#: (0x55B3C17E17D6) basic_ios.h:50            - std::ctype<char> const& std::__check_facet<std::ctype<char> >(std::ctype<char> const*)
         2#: (0x55B3C17E17D6) basic_ios.h:454           - std::basic_ios<char, std::char_traits<char> >::widen(char) const
         3#: (0x55B3C17E17D6) ostream:742               - std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char>>&)
         4#: (0x55B3C17E17D6) ostream:121               - std::ostream::operator<<(std::ostream& (*)(std::ostream&))
         5#: (0x55B3C17E17D6) guiutil_font.cpp:118      - GUIUtil::weightToArg(QFont::Weight)
         6#: (0x55B3C17A189A) bitcoin.cpp:702           - GuiMain(int, char**)
         7#: (0x7F88E4B1E1CA) libc_start_call_main.h:74 - __libc_start_call_main
         8#: (0x7F88E4B1E28B) libc-start.c:128          - call_init
         9#: (0x7F88E4B1E28B) libc-start.c:347          - __libc_start_main_impl
        10#: (0x55B3C179C545) <unknown-file>            - ???
      dash-qt: qt/guiutil_font.cpp:119: int GUIUtil::weightToArg(const QFont::Weight): Assertion `mapWeight.count(weight)' failed.
      Aborted (core dumped)
      ```

    </details>

  * A helper, `qstrprintf()` has been introduced to streamline debug print logging based on a review suggestion ([comment](dashpay/dash#6831 (comment))).

  ## Breaking Changes

  None expected.

  ## How Has This Been Tested?

  On build 2dc48deb running Dash Qt on `./src/qt/dash-qt --testnet --font-family="Comic Sans MS"`

  ![Dash Qt running with Comic Sans](https://github.com/user-attachments/assets/90d40d00-24ed-4190-b2b4-bfee61933490)

  On build 2dc48deb running Dash Qt on `./src/qt/dash-qt --testnet --font-family="Fictional Sans Serif"`

  ![Dash Qt existing when attempting to run with invalid font](https://github.com/user-attachments/assets/0e6009ef-5046-4755-a692-2d5c5f368148)

  ## Checklist:

  - [x] I have performed a self-review of my own code
  - [x] I have commented my code, particularly in hard-to-understand areas
  - [x] I have added or updated relevant unit/integration/functional/e2e tests **(note: N/A)**
  - [x] I have made corresponding changes to the documentation **(note: N/A)**
  - [x] I have assigned this pull request to a milestone _(for repository code-owners and collaborators only)_

ACKs for top commit:
  UdjinM6:
    Light ACK b6d418a

Tree-SHA512: defdbd3864405c22b4d3cd381a58331b1ad62785f9b037cbdc3e6fd67045039ec116cabb18ddef5296c0e9647c50efe7b22e685c994cf31606328d917a349747

Author: PastaPastaPasta

src/Makefile.qt.include

@@ -139,6 +139,7 @@ BITCOIN_QT_H = \
   qt/proposalwizard.h \
   qt/guiconstants.h \
   qt/guiutil.h \
+  qt/guiutil_font.h \
   qt/initexecutor.h \
   qt/intro.h \
   qt/macdockiconhandler.h \
@@ -230,6 +231,7 @@ BITCOIN_QT_BASE_CPP = \
   qt/clientmodel.cpp \
   qt/csvmodelwriter.cpp \
   qt/guiutil.cpp \
+  qt/guiutil_font.cpp \
   qt/initexecutor.cpp \
   qt/intro.cpp \
   qt/modaloverlay.cpp \

src/qt/addressbookpage.cpp

@@ -14,6 +14,7 @@
 #include <qt/csvmodelwriter.h>
 #include <qt/editaddressdialog.h>
 #include <qt/guiutil.h>
+#include <qt/guiutil_font.h>
 #include <qt/optionsmodel.h>
 #include <qt/qrdialog.h>
 

src/qt/addresstablemodel.cpp

@@ -6,6 +6,7 @@
 #include <qt/addresstablemodel.h>
 
 #include <qt/guiutil.h>
+#include <qt/guiutil_font.h>
 #include <qt/walletmodel.h>
 
 #include <key_io.h>

src/qt/appearancewidget.cpp

@@ -20,19 +20,22 @@
 
 AppearanceWidget::AppearanceWidget(QWidget* parent) :
     QWidget(parent),
-    ui{new Ui::AppearanceWidget()}
+    ui{new Ui::AppearanceWidget()},
+    prevTheme{GUIUtil::getActiveTheme()},
+    prevScale{GUIUtil::g_font_registry.GetFontScale()},
+    prevFontFamily{GUIUtil::g_font_registry.GetFont()},
+    prevWeightNormal{GUIUtil::g_font_registry.GetWeightNormal()},
+    prevWeightBold{GUIUtil::g_font_registry.GetWeightBold()}
 {
     ui->setupUi(this);
 
     for (const QString& entry : GUIUtil::listThemes()) {
         ui->theme->addItem(entry, QVariant(entry));
     }
 
-    GUIUtil::FontFamily fontSystem = GUIUtil::FontFamily::SystemDefault;
-    GUIUtil::FontFamily fontMontserrat = GUIUtil::FontFamily::Montserrat;
-
-    ui->fontFamily->addItem(GUIUtil::fontFamilyToString(fontSystem), QVariant(static_cast<int>(fontSystem)));
-    ui->fontFamily->addItem(GUIUtil::fontFamilyToString(fontMontserrat), QVariant(static_cast<int>(fontMontserrat)));
+    for (size_t idx{0}; idx < GUIUtil::g_fonts_known.size(); idx++) {
+        ui->fontFamily->addItem(GUIUtil::g_fonts_known[idx], QVariant((uint16_t)idx));
+    }
 
     updateWeightSlider();
 
@@ -61,34 +64,74 @@ AppearanceWidget::~AppearanceWidget()
         if (prevTheme != GUIUtil::getActiveTheme()) {
             updateTheme(prevTheme);
         }
-        if (prevFontFamily != GUIUtil::getFontFamily()) {
-            GUIUtil::setFontFamily(prevFontFamily);
+        if (prevFontFamily != GUIUtil::g_font_registry.GetFont()) {
+            const bool setfont_ret{GUIUtil::g_font_registry.SetFont(prevFontFamily)};
+            assert(setfont_ret);
+            GUIUtil::setApplicationFont();
         }
-        if (prevScale != GUIUtil::getFontScale()) {
-            GUIUtil::setFontScale(prevScale);
+        if (prevScale != GUIUtil::g_font_registry.GetFontScale()) {
+            GUIUtil::g_font_registry.SetFontScale(prevScale);
         }
-        if (prevWeightNormal != GUIUtil::getFontWeightNormal()) {
-            GUIUtil::setFontWeightNormal(prevWeightNormal);
+        if (prevWeightNormal != GUIUtil::g_font_registry.GetWeightNormal()) {
+            GUIUtil::g_font_registry.SetWeightNormal(prevWeightNormal);
         }
-        if (prevWeightBold != GUIUtil::getFontWeightBold()) {
-            GUIUtil::setFontWeightBold(prevWeightBold);
+        if (prevWeightBold != GUIUtil::g_font_registry.GetWeightBold()) {
+            GUIUtil::g_font_registry.SetWeightBold(prevWeightBold);
         }
+        GUIUtil::setApplicationFont();
+        GUIUtil::updateFonts();
     }
     delete ui;
 }
 
 void AppearanceWidget::setModel(OptionsModel* _model)
 {
     this->model = _model;
+    if (!_model) return;
+
+    mapper->setModel(_model);
+    mapper->addMapping(ui->theme, OptionsModel::Theme);
+    mapper->addMapping(ui->fontFamily, OptionsModel::FontFamily);
+    mapper->addMapping(ui->fontScaleSlider, OptionsModel::FontScale);
+    mapper->addMapping(ui->fontWeightNormalSlider, OptionsModel::FontWeightNormal);
+    mapper->addMapping(ui->fontWeightBoldSlider, OptionsModel::FontWeightBold);
+
+    const QSignalBlocker fontFamilyBlocker(ui->fontFamily);
+    const QSignalBlocker fontScaleBlocker(ui->fontScaleSlider);
+    const QSignalBlocker fontWeightNormalBlocker(ui->fontWeightNormalSlider);
+    const QSignalBlocker fontWeightBoldBlocker(ui->fontWeightBoldSlider);
+
+    mapper->toFirst();
+
+    const bool override_family{_model->isOptionOverridden("-font-family")};
+    if (override_family) {
+        ui->fontFamily->setEnabled(false);
+        if (const auto idx{ui->fontFamily->findText(GUIUtil::g_font_registry.GetFont())}; idx != -1) {
+            ui->fontFamily->setCurrentIndex(idx);
+        }
+    }
+
+    if (_model->isOptionOverridden("-font-scale")) {
+        ui->fontScaleSlider->setEnabled(false);
+        ui->fontScaleSlider->setValue(GUIUtil::g_font_registry.GetFontScale());
+    }
 
-    if (_model) {
-        mapper->setModel(_model);
-        mapper->addMapping(ui->theme, OptionsModel::Theme);
-        mapper->addMapping(ui->fontFamily, OptionsModel::FontFamily);
-        mapper->addMapping(ui->fontScaleSlider, OptionsModel::FontScale);
-        mapper->addMapping(ui->fontWeightNormalSlider, OptionsModel::FontWeightNormal);
-        mapper->addMapping(ui->fontWeightBoldSlider, OptionsModel::FontWeightBold);
-        mapper->toFirst();
+    if (bool is_overridden{_model->isOptionOverridden("-font-weight-normal")}; is_overridden || override_family) {
+        if (is_overridden) {
+            ui->fontWeightNormalSlider->setEnabled(false);
+        }
+        if (const auto idx{GUIUtil::g_font_registry.WeightToIdx(GUIUtil::g_font_registry.GetWeightNormal())}; idx != -1) {
+            ui->fontWeightNormalSlider->setValue(idx);
+        }
+    }
+
+    if (bool is_overridden{_model->isOptionOverridden("-font-weight-bold")}; is_overridden || override_family) {
+        if (is_overridden) {
+            ui->fontWeightBoldSlider->setEnabled(false);
+        }
+        if (const auto idx{GUIUtil::g_font_registry.WeightToIdx(GUIUtil::g_font_registry.GetWeightBold())}; idx != -1) {
+            ui->fontWeightBoldSlider->setValue(idx);
+        }
     }
 }
 
@@ -111,13 +154,17 @@ void AppearanceWidget::updateTheme(const QString& theme)
 
 void AppearanceWidget::updateFontFamily(int index)
 {
-    GUIUtil::setFontFamily(static_cast<GUIUtil::FontFamily>(ui->fontFamily->itemData(index).toInt()));
+    const bool setfont_ret{GUIUtil::g_font_registry.SetFont(GUIUtil::g_fonts_known[ui->fontFamily->itemData(index).toInt()])};
+    assert(setfont_ret);
+    GUIUtil::setApplicationFont();
+    GUIUtil::updateFonts();
     updateWeightSlider(true);
 }
 
 void AppearanceWidget::updateFontScale(int nScale)
 {
-    GUIUtil::setFontScale(nScale);
+    GUIUtil::g_font_registry.SetFontScale(nScale);
+    GUIUtil::updateFonts();
 }
 
 void AppearanceWidget::updateFontWeightNormal(int nValue, bool fForce)
@@ -128,7 +175,9 @@ void AppearanceWidget::updateFontWeightNormal(int nValue, bool fForce)
     }
     const QSignalBlocker blocker(ui->fontWeightNormalSlider);
     ui->fontWeightNormalSlider->setValue(nSliderValue);
-    GUIUtil::setFontWeightNormal(GUIUtil::supportedWeightFromIndex(ui->fontWeightNormalSlider->value()));
+    GUIUtil::g_font_registry.SetWeightNormal(GUIUtil::g_font_registry.IdxToWeight(ui->fontWeightNormalSlider->value()));
+    GUIUtil::setApplicationFont();
+    GUIUtil::updateFonts();
 }
 
 void AppearanceWidget::updateFontWeightBold(int nValue, bool fForce)
@@ -139,22 +188,24 @@ void AppearanceWidget::updateFontWeightBold(int nValue, bool fForce)
     }
     const QSignalBlocker blocker(ui->fontWeightBoldSlider);
     ui->fontWeightBoldSlider->setValue(nSliderValue);
-    GUIUtil::setFontWeightBold(GUIUtil::supportedWeightFromIndex(ui->fontWeightBoldSlider->value()));
+    GUIUtil::g_font_registry.SetWeightBold(GUIUtil::g_font_registry.IdxToWeight(ui->fontWeightBoldSlider->value()));
+    GUIUtil::setApplicationFont();
+    GUIUtil::updateFonts();
 }
 
 void AppearanceWidget::updateWeightSlider(const bool fForce)
 {
-    int nMaximum = GUIUtil::getSupportedWeights().size() - 1;
+    int nMaximum = GUIUtil::g_font_registry.GetSupportedWeights().size() - 1;
 
     ui->fontWeightNormalSlider->setMinimum(0);
     ui->fontWeightNormalSlider->setMaximum(nMaximum);
 
     ui->fontWeightBoldSlider->setMinimum(0);
     ui->fontWeightBoldSlider->setMaximum(nMaximum);
 
-    if (fForce || !GUIUtil::isSupportedWeight(prevWeightNormal) || !GUIUtil::isSupportedWeight(prevWeightBold)) {
-        int nIndexNormal = GUIUtil::supportedWeightToIndex(GUIUtil::getSupportedFontWeightNormalDefault());
-        int nIndexBold = GUIUtil::supportedWeightToIndex(GUIUtil::getSupportedFontWeightBoldDefault());
+    if (fForce || !GUIUtil::g_font_registry.IsValidWeight(prevWeightNormal) || !GUIUtil::g_font_registry.IsValidWeight(prevWeightBold)) {
+        int nIndexNormal = GUIUtil::g_font_registry.WeightToIdx(GUIUtil::g_font_registry.GetWeightNormalDefault());
+        int nIndexBold = GUIUtil::g_font_registry.WeightToIdx(GUIUtil::g_font_registry.GetWeightBoldDefault());
         assert(nIndexNormal != -1 && nIndexBold != -1);
         updateFontWeightNormal(nIndexNormal, true);
         updateFontWeightBold(nIndexBold, true);

src/qt/appearancewidget.h

@@ -8,6 +8,7 @@
 #include <QWidget>
 
 #include <qt/guiutil.h>
+#include <qt/guiutil_font.h>
 
 namespace Ui {
 class AppearanceWidget;
@@ -47,11 +48,11 @@ private Q_SLOTS:
     QDataWidgetMapper* mapper;
     OptionsModel* model;
     bool fAcceptChanges{false};
-    QString prevTheme{GUIUtil::getActiveTheme()};
-    int prevScale{GUIUtil::getFontScale()};
-    GUIUtil::FontFamily prevFontFamily{GUIUtil::getFontFamily()};
-    QFont::Weight prevWeightNormal{GUIUtil::getFontWeightNormal()};
-    QFont::Weight prevWeightBold{GUIUtil::getFontWeightBold()};
+    QString prevTheme;
+    int prevScale;
+    QString prevFontFamily;
+    QFont::Weight prevWeightNormal;
+    QFont::Weight prevWeightBold;
 
     void updateWeightSlider(bool fForce = false);
 };

src/qt/askpassphrasedialog.cpp

@@ -12,6 +12,7 @@
 
 #include <qt/guiconstants.h>
 #include <qt/guiutil.h>
+#include <qt/guiutil_font.h>
 #include <qt/walletmodel.h>
 
 #include <support/allocators/secure.h>
@@ -30,7 +31,7 @@ AskPassphraseDialog::AskPassphraseDialog(Mode _mode, QWidget *parent, SecureStri
 {
     ui->setupUi(this);
 
-    GUIUtil::setFont({ui->capsLabel}, GUIUtil::FontWeight::Bold);
+    GUIUtil::setFont({ui->capsLabel}, {GUIUtil::g_font_registry.GetWeightBold()});
 
     GUIUtil::updateFonts();
 

src/qt/bitcoin.cpp

@@ -22,6 +22,7 @@
 #include <qt/clientmodel.h>
 #include <qt/guiconstants.h>
 #include <qt/guiutil.h>
+#include <qt/guiutil_font.h>
 #include <qt/initexecutor.h>
 #include <qt/intro.h>
 #include <qt/networkstyle.h>
@@ -488,10 +489,10 @@ static void SetupUIArgs(ArgsManager& argsman)
 {
     argsman.AddArg("-choosedatadir", strprintf(QObject::tr("Choose data directory on startup (default: %u)").toStdString(), DEFAULT_CHOOSE_DATADIR), ArgsManager::ALLOW_ANY, OptionsCategory::GUI);
     argsman.AddArg("-custom-css-dir", "Set a directory which contains custom css files. Those will be used as stylesheets for the UI.", ArgsManager::ALLOW_ANY, OptionsCategory::GUI);
-    argsman.AddArg("-font-family", QObject::tr("Set the font family. Possible values: %1. (default: %2)").arg("SystemDefault, Montserrat").arg(GUIUtil::fontFamilyToString(GUIUtil::getFontFamilyDefault())).toStdString(), ArgsManager::ALLOW_ANY, OptionsCategory::GUI);
-    argsman.AddArg("-font-scale", QObject::tr("Set a scale factor which gets applied to the base font size. Possible range %1 (smallest fonts) to %2 (largest fonts). (default: %3)").arg(-100).arg(100).arg(GUIUtil::getFontScaleDefault()).toStdString(), ArgsManager::ALLOW_ANY, OptionsCategory::GUI);
-    argsman.AddArg("-font-weight-bold", QObject::tr("Set the font weight for bold texts. Possible range %1 to %2 (default: %3)").arg(0).arg(8).arg(GUIUtil::weightToArg(GUIUtil::getFontWeightBoldDefault())).toStdString(), ArgsManager::ALLOW_ANY, OptionsCategory::GUI);
-    argsman.AddArg("-font-weight-normal", QObject::tr("Set the font weight for normal texts. Possible range %1 to %2 (default: %3)").arg(0).arg(8).arg(GUIUtil::weightToArg(GUIUtil::getFontWeightNormalDefault())).toStdString(), ArgsManager::ALLOW_ANY, OptionsCategory::GUI);
+    argsman.AddArg("-font-family", QObject::tr("Set the font family. Possible values: %1. (default: %2)").arg(Join(GUIUtil::g_fonts_known, ", ")).arg(GUIUtil::FontRegistry::DEFAULT_FONT).toStdString(), ArgsManager::ALLOW_ANY, OptionsCategory::GUI);
+    argsman.AddArg("-font-scale", QObject::tr("Set a scale factor which gets applied to the base font size. Possible range %1 (smallest fonts) to %2 (largest fonts). (default: %3)").arg(-100).arg(100).arg(GUIUtil::FontRegistry::DEFAULT_FONT_SCALE).toStdString(), ArgsManager::ALLOW_ANY, OptionsCategory::GUI);
+    argsman.AddArg("-font-weight-bold", QObject::tr("Set the font weight for bold texts. Possible range %1 to %2 (default: %3)").arg(0).arg(8).arg(GUIUtil::weightToArg(GUIUtil::FontRegistry::TARGET_WEIGHT_BOLD)).toStdString(), ArgsManager::ALLOW_ANY, OptionsCategory::GUI);
+    argsman.AddArg("-font-weight-normal", QObject::tr("Set the font weight for normal texts. Possible range %1 to %2 (default: %3)").arg(0).arg(8).arg(GUIUtil::weightToArg(GUIUtil::FontRegistry::TARGET_WEIGHT_NORMAL)).toStdString(), ArgsManager::ALLOW_ANY, OptionsCategory::GUI);
     argsman.AddArg("-lang=<lang>", QObject::tr("Set language, for example \"de_DE\" (default: system locale)").toStdString(), ArgsManager::ALLOW_ANY, OptionsCategory::GUI);
     argsman.AddArg("-min", QObject::tr("Start minimized").toStdString(), ArgsManager::ALLOW_ANY, OptionsCategory::GUI);
     argsman.AddArg("-resetguisettings", QObject::tr("Reset all settings changed in the GUI").toStdString(), ArgsManager::ALLOW_ANY, OptionsCategory::GUI);
@@ -664,56 +665,53 @@ int GuiMain(int argc, char* argv[])
     GUIUtil::LogQtInfo();
     // Load custom application fonts and setup font management
     if (!GUIUtil::loadFonts()) {
-        QMessageBox::critical(nullptr, PACKAGE_NAME,
-                              QObject::tr("Error: Failed to load application fonts."));
+        QMessageBox::critical(nullptr, PACKAGE_NAME, QObject::tr("Error: Failed to load application fonts."));
         return EXIT_FAILURE;
     }
     // Load GUI settings from QSettings
     app.createOptionsModel(gArgs.GetBoolArg("-resetguisettings", false));
     // Validate/set font family
     if (gArgs.IsArgSet("-font-family")) {
-        GUIUtil::FontFamily family;
-        QString strFamily = gArgs.GetArg("-font-family", GUIUtil::fontFamilyToString(GUIUtil::getFontFamilyDefault()).toStdString()).c_str();
-        try {
-            family = GUIUtil::fontFamilyFromString(strFamily);
-        } catch (const std::exception& e) {
-            QMessageBox::critical(nullptr, PACKAGE_NAME,
-                                  QObject::tr("Error: Specified font-family invalid. Valid values: %1.").arg("SystemDefault, Montserrat"));
+        QString family = gArgs.GetArg("-font-family", GUIUtil::FontRegistry::DEFAULT_FONT.toUtf8().toStdString()).c_str();
+        if (!GUIUtil::g_font_registry.RegisterFont(family) || !GUIUtil::g_font_registry.SetFont(family)) {
+            QMessageBox::critical(nullptr, PACKAGE_NAME, QObject::tr("Error: Font \"%1\" could not be loaded.").arg(family));
             return EXIT_FAILURE;
         }
-        GUIUtil::setFontFamily(family);
     }
     // Validate/set normal font weight
     if (gArgs.IsArgSet("-font-weight-normal")) {
         QFont::Weight weight;
-        if (!GUIUtil::weightFromArg(gArgs.GetIntArg("-font-weight-normal", GUIUtil::weightToArg(GUIUtil::getFontWeightNormal())), weight)) {
+        if (!GUIUtil::weightFromArg(gArgs.GetIntArg("-font-weight-normal", GUIUtil::weightToArg(GUIUtil::g_font_registry.GetWeightNormal())), weight)) {
             QMessageBox::critical(nullptr, PACKAGE_NAME,
                                   QObject::tr("Error: Specified font-weight-normal invalid. Valid range %1 to %2.").arg(0).arg(8));
             return EXIT_FAILURE;
         }
-        GUIUtil::setFontWeightNormal(weight);
+        GUIUtil::g_font_registry.SetWeightNormal(weight);
     }
     // Validate/set bold font weight
     if (gArgs.IsArgSet("-font-weight-bold")) {
         QFont::Weight weight;
-        if (!GUIUtil::weightFromArg(gArgs.GetIntArg("-font-weight-bold", GUIUtil::weightToArg(GUIUtil::getFontWeightBold())), weight)) {
+        if (!GUIUtil::weightFromArg(gArgs.GetIntArg("-font-weight-bold", GUIUtil::weightToArg(GUIUtil::g_font_registry.GetWeightBold())), weight)) {
             QMessageBox::critical(nullptr, PACKAGE_NAME,
                                   QObject::tr("Error: Specified font-weight-bold invalid. Valid range %1 to %2.").arg(0).arg(8));
             return EXIT_FAILURE;
         }
-        GUIUtil::setFontWeightBold(weight);
+        GUIUtil::g_font_registry.SetWeightBold(weight);
     }
     // Validate/set font scale
     if (gArgs.IsArgSet("-font-scale")) {
         const int nScaleMin = -100, nScaleMax = 100;
-        int nScale = gArgs.GetIntArg("-font-scale", GUIUtil::getFontScale());
+        int nScale = gArgs.GetIntArg("-font-scale", GUIUtil::g_font_registry.GetFontScale());
         if (nScale < nScaleMin || nScale > nScaleMax) {
             QMessageBox::critical(nullptr, PACKAGE_NAME,
                                   QObject::tr("Error: Specified font-scale invalid. Valid range %1 to %2.").arg(nScaleMin).arg(nScaleMax));
             return EXIT_FAILURE;
         }
-        GUIUtil::setFontScale(nScale);
+        GUIUtil::g_font_registry.SetFontScale(nScale);
     }
+    // Apply font changes
+    GUIUtil::updateFonts();
+    GUIUtil::setApplicationFont();
     // Validate/set custom css directory
     if (gArgs.IsArgSet("-custom-css-dir")) {
         fs::path customDir = gArgs.GetPathArg("-custom-css-dir");

src/qt/bitcoingui.cpp

@@ -10,6 +10,7 @@
 #include <qt/createwalletdialog.h>
 #include <qt/guiconstants.h>
 #include <qt/guiutil.h>
+#include <qt/guiutil_font.h>
 #include <qt/modaloverlay.h>
 #include <qt/networkstyle.h>
 #include <qt/notificator.h>
@@ -757,7 +758,7 @@ void BitcoinGUI::createToolBars()
         connect(tabGroup, qOverload<QAbstractButton *, bool>(&QButtonGroup::buttonToggled), this, &BitcoinGUI::highlightTabButton);
 
         for (auto button : tabGroup->buttons()) {
-            GUIUtil::setFont({button}, GUIUtil::FontWeight::Normal, 16);
+            GUIUtil::setFont({button}, {GUIUtil::g_font_registry.GetWeightNormal(), 16});
             button->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Preferred);
             button->setToolTip(button->statusTip());
             button->setCheckable(true);
@@ -1239,7 +1240,7 @@ void BitcoinGUI::openClicked()
 
 void BitcoinGUI::highlightTabButton(QAbstractButton *button, bool checked)
 {
-    GUIUtil::setFont({button}, checked ? GUIUtil::FontWeight::Bold : GUIUtil::FontWeight::Normal, 16);
+    GUIUtil::setFont({button}, {checked ? GUIUtil::g_font_registry.GetWeightBold() : GUIUtil::g_font_registry.GetWeightNormal(), 16});
     GUIUtil::updateFonts();
 }
 

src/qt/coincontroldialog.cpp

@@ -13,6 +13,7 @@
 #include <qt/addresstablemodel.h>
 #include <qt/bitcoinunits.h>
 #include <qt/guiutil.h>
+#include <qt/guiutil_font.h>
 #include <qt/optionsmodel.h>
 #include <qt/walletmodel.h>
 
@@ -57,7 +58,7 @@ CoinControlDialog::CoinControlDialog(CCoinControl& coin_control, WalletModel* _m
                       ui->labelCoinControlFeeText,
                       ui->labelCoinControlAfterFeeText,
                       ui->labelCoinControlChangeText
-                     }, GUIUtil::FontWeight::Bold);
+                     }, {GUIUtil::g_font_registry.GetWeightBold()});
 
     GUIUtil::updateFonts();