Rework themes to easily use light/dark palette, using only different icons

- Renamed themes:
  - "colorful" to "default" and "colorful_dark" to "default_dark"
  - "default" to "monochrome" and "default_dark" to "monochrome_dark"
  - "colorful_midnight_blue" to "qdarkstyle_midnight_blue"
  - "qdarkstyle_midnight_blue" to "qdarkstyle_midnight_blue_monochrome"
  - qdarkstyle is renamed from "Dark" to "Mine Shaft" in the UI
- default and monochrome themes all use the same qss stylesheet
- Remove the ability to select "default_dark" directly
- Add "qdarkstyle_monochrome" theme
- Remove duplicated icon files

src/yuzu/aboutdialog.ui

@@ -164,7 +164,6 @@ p, li { white-space: pre-wrap; }
   </layout>
  </widget>
  <resources>
-  <include location="../../dist/qt_themes_default/default/default.qrc"/>
   <include location="../../dist/qt_themes/default/default.qrc"/>
  </resources>
  <connections>

src/yuzu/main.cpp

@@ -7,7 +7,6 @@
 #include <fstream>
 #include <iostream>
 #include <memory>
-#include <QStyleFactory>
 #include <thread>
 
 #include "core/hle/service/am/applet_manager.h"
@@ -330,12 +329,11 @@ GMainWindow::GMainWindow(std::unique_ptr<QtConfig> config_, bool has_broken_vulk
     statusBar()->hide();
 
     startup_icon_theme = QIcon::themeName();
-    // fallback can only be set once, colorful theme icons are okay on both light/dark
-    QIcon::setFallbackThemeName(QStringLiteral("colorful"));
+    // fallback can only be set once, default theme icons are okay on both light/dark
+    QIcon::setFallbackThemeName(QStringLiteral("default"));
     QIcon::setFallbackSearchPaths(QStringList(QStringLiteral(":/icons")));
 
     default_theme_paths = QIcon::themeSearchPaths();
-    UpdateUITheme();
 
     SetDiscordEnabled(UISettings::values.enable_discord_presence.GetValue());
     discord_rpc->Update();
@@ -3799,8 +3797,6 @@ void GMainWindow::OnConfigure() {
         multiplayer_state->UpdateCredentials();
     }
 
-    emit UpdateThemedIcons();
-
     const auto reload = UISettings::values.is_game_list_reload_pending.exchange(false);
     if (reload || Settings::values.language_index.GetValue() != old_language_index) {
         game_list->PopulateAsync(UISettings::values.game_dirs);
@@ -4845,8 +4841,10 @@ void GMainWindow::UpdateUITheme() {
 void GMainWindow::UpdateIcons(const QString& theme_used) {
     // Append _dark to the theme name to use dark variant icons
     if (CheckDarkMode()) {
+        LOG_DEBUG(Frontend, "Using icons from: {}", theme_used.toStdString() + "_dark");
         QIcon::setThemeName(theme_used + QStringLiteral("_dark"));
     } else {
+        LOG_DEBUG(Frontend, "Using icons from: {}", theme_used.toStdString());
         QIcon::setThemeName(theme_used);
     }
 
@@ -5041,9 +5039,9 @@ bool GMainWindow::CheckDarkMode() {
     // Using the freedesktop specifications for checking dark mode
     LOG_INFO(Frontend, "Retrieving theme from freedesktop color-scheme...");
     gdbus_arguments << QStringLiteral("--dest=org.freedesktop.portal.Desktop")
-                   << QStringLiteral("--object-path /org/freedesktop/portal/desktop")
-                   << QStringLiteral("--method org.freedesktop.portal.Settings.Read "
-                                        "org.freedesktop.appearance color-scheme");
+                    << QStringLiteral("--object-path /org/freedesktop/portal/desktop")
+                    << QStringLiteral("--method org.freedesktop.portal.Settings.Read")
+                    << QStringLiteral("org.freedesktop.appearance color-scheme");
     process.start(QStringLiteral("gdbus call --session"), gdbus_arguments);
     process.waitForFinished(1000);
     QByteArray dbus_output = process.readAllStandardOutput();
@@ -5107,7 +5105,8 @@ void GMainWindow::changeEvent(QEvent* event) {
 
             UpdateUITheme();
         }
-    } else QWidget::changeEvent(event);
+    }
+    QWidget::changeEvent(event);
 }
 
 void GMainWindow::LoadTranslation() {

src/yuzu/main.h

@@ -166,7 +166,6 @@ class GMainWindow : public QMainWindow {
 public:
     void filterBarSetChecked(bool state);
     static bool CheckDarkMode();
-    void UpdateUITheme();
     explicit GMainWindow(std::unique_ptr<QtConfig> config_, bool has_broken_vulkan);
     ~GMainWindow() override;
 

src/yuzu/uisettings.cpp

@@ -24,11 +24,11 @@ namespace UISettings {
 
 const Themes included_themes{{
     {"Default", "default"},
-    {"Default Colorful", "colorful"},
-    {"Dark", "qdarkstyle"},
-    {"Dark Colorful", "colorful_dark"},
+    {"Default monochrome", "monochrome"},
+    {"Mine Shaft", "qdarkstyle"},
+    {"Mine Shaft monochrome", "qdarkstyle_monochrome"},
     {"Midnight Blue", "qdarkstyle_midnight_blue"},
-    {"Midnight Blue Colorful", "colorful_midnight_blue"},
+    {"Midnight Blue monochrome", "qdarkstyle_midnight_blue_monochrome"},
 }};
 
 Values values = {};

src/yuzu/uisettings.h

@@ -48,7 +48,7 @@ struct Shortcut {
     ContextualShortcut shortcut;
 };
 
-static constexpr std::string_view default_theme{"colorful"};
+static constexpr std::string_view default_theme{"default"};
 
 using Themes = std::array<std::pair<const char*, const char*>, 6>;
 extern const Themes included_themes;