Improve macOS platform integration.

- Allow switching between themes without restart (except classic)
- Rework icon loading and recolouring logic to react to theme changes
- Automatically react to light/dark theme change
- Remove explicit selection of monochrome tray icon variant (selected
  automatically now)
- Update theme background colours for Big Sur
- Update application icon to match Big Sur HIG

The tray icon doesn't respond perfectly to theme changes yet on Big Sur,
since we need different icons for dark and light theme and cannot simply
let the OS recolour the icon for us (we do that, too, but only as an
additional fallback). At the moment, there is no signal to listen to
that would allow this.

This patch adds a few generic methods to OSUtils for detecting and
communicating theme changes, which are only stubs for Windows and Linux at
the moment and need to be implemented in future commits.

Fixes keepassxreboot#4933
Fixes keepassxreboot#5349

.gitattributes

@@ -11,3 +11,6 @@ AppImage-Recipe.sh export-ignore
 # github-linguist language hints
 *.h linguist-language=C++
 *.cpp linguist-language=C++
+
+# binary files
+*.ai binary

src/gui/Application.cpp

@@ -23,6 +23,7 @@
 #include "core/Bootstrap.h"
 #include "core/Config.h"
 #include "core/Global.h"
+#include "gui/Icons.h"
 #include "gui/MainWindow.h"
 #include "gui/MessageBox.h"
 #include "gui/osutils/OSUtils.h"
@@ -127,6 +128,12 @@ Application::Application(int& argc, char** argv)
         qWarning()
             << QObject::tr("The lock file could not be created. Single-instance mode disabled.").toUtf8().constData();
     }
+
+    connect(osUtils, &OSUtilsBase::interfaceThemeChanged, this, [this]() {
+        if (config()->get(Config::GUI_ApplicationTheme).toString() != "classic") {
+            applyTheme();
+        }
+    });
 }
 
 Application::~Application()
@@ -174,15 +181,15 @@ void Application::applyTheme()
         }
 #endif
     }
-
+    QPixmapCache::clear();
     if (appTheme == "light") {
-        setStyle(new LightStyle);
-        // Workaround Qt 5.15+ bug
-        setPalette(style()->standardPalette());
+        auto* s = new LightStyle;
+        setPalette(s->standardPalette());
+        setStyle(s);
     } else if (appTheme == "dark") {
-        setStyle(new DarkStyle);
-        // Workaround Qt 5.15+ bug
-        setPalette(style()->standardPalette());
+        auto* s = new DarkStyle;
+        setPalette(s->standardPalette());
+        setStyle(s);
         m_darkTheme = true;
     } else {
         // Classic mode, don't check for dark theme on Windows

src/gui/ApplicationSettingsWidget.cpp

@@ -251,8 +251,12 @@ void ApplicationSettingsWidget::loadSettings()
     }
 
     m_generalUi->trayIconAppearance->clear();
+#ifdef Q_OS_MACOS
+    m_generalUi->trayIconAppearance->addItem(tr("Monochrome"), "monochrome");
+#else
     m_generalUi->trayIconAppearance->addItem(tr("Monochrome (light)"), "monochrome-light");
     m_generalUi->trayIconAppearance->addItem(tr("Monochrome (dark)"), "monochrome-dark");
+#endif
     m_generalUi->trayIconAppearance->addItem(tr("Colorful"), "colorful");
     int trayIconIndex = m_generalUi->trayIconAppearance->findData(icons()->trayIconAppearance());
     if (trayIconIndex > 0) {

src/gui/Icons.cpp

@@ -19,6 +19,8 @@
 #include "Icons.h"
 
 #include <QBitmap>
+#include <QIconEngine>
+#include <QPaintDevice>
 #include <QPainter>
 #include <QStyle>
 
@@ -27,8 +29,24 @@
 #include "gui/MainWindow.h"
 #include "gui/osutils/OSUtils.h"
 
+class AdaptiveIconEngine : public QIconEngine
+{
+public:
+    explicit AdaptiveIconEngine(QIcon baseIcon);
+    void paint(QPainter* painter, const QRect& rect, QIcon::Mode mode, QIcon::State state) override;
+    QPixmap pixmap(const QSize& size, QIcon::Mode mode, QIcon::State state) override;
+    QIconEngine* clone() const override;
+
+private:
+    QIcon m_baseIcon;
+};
+
 Icons* Icons::m_instance(nullptr);
 
+Icons::Icons()
+{
+}
+
 QIcon Icons::applicationIcon()
 {
     return icon("keepassxc", false);
@@ -47,45 +65,102 @@ QString Icons::trayIconAppearance() const
     return iconAppearance;
 }
 
-QIcon Icons::trayIcon()
+QIcon Icons::trayIcon(QString style)
 {
-    return trayIconUnlocked();
-}
+    if (style == "unlocked") {
+        style.clear();
+    }
+    if (!style.isEmpty()) {
+        style = "-" + style;
+    }
 
-QIcon Icons::trayIconLocked()
-{
     auto iconApperance = trayIconAppearance();
-
-    if (iconApperance == "monochrome-light") {
-        return icon("keepassxc-monochrome-light-locked", false);
+    if (!iconApperance.startsWith("monochrome")) {
+        return icon(QString("keepassxc%1").arg(style), false);
     }
-    if (iconApperance == "monochrome-dark") {
-        return icon("keepassxc-monochrome-dark-locked", false);
+
+    QIcon i;
+#ifdef Q_OS_MACOS
+    if (osUtils->isStatusBarDark()) {
+        i = icon(QString("keepassxc-monochrome-light%1").arg(style), false);
+    } else {
+        i = icon(QString("keepassxc-monochrome-dark%1").arg(style), false);
     }
-    return icon("keepassxc-locked", false);
+#else
+    i = icon(QString("keepassxc-%1%2").arg(iconApperance, style), false);
+#endif
+#if QT_VERSION >= QT_VERSION_CHECK(5, 6, 0)
+    // Set as mask to allow the operating system to recolour the tray icon. This may look weird
+    // if we failed to detect the status bar background colour correctly, but it is certainly
+    // better than a barely visible icon and even if we did guess correctly, it allows for better
+    // integration should the system's preferred colours not be 100% black or white.
+    i.setIsMask(true);
+#endif
+    return i;
+}
+
+QIcon Icons::trayIconLocked()
+{
+    return trayIcon("locked");
 }
 
 QIcon Icons::trayIconUnlocked()
 {
-    auto iconApperance = trayIconAppearance();
+    return trayIcon("unlocked");
+}
 
-    if (iconApperance == "monochrome-light") {
-        return icon("keepassxc-monochrome-light", false);
-    }
-    if (iconApperance == "monochrome-dark") {
-        return icon("keepassxc-monochrome-dark", false);
-    }
-    return icon("keepassxc", false);
+AdaptiveIconEngine::AdaptiveIconEngine(QIcon baseIcon)
+    : QIconEngine()
+    , m_baseIcon(std::move(baseIcon))
+{
 }
 
-QIcon Icons::icon(const QString& name, bool recolor, const QColor& overrideColor)
+void AdaptiveIconEngine::paint(QPainter* painter, const QRect& rect, QIcon::Mode mode, QIcon::State state)
 {
-    QIcon icon = m_iconCache.value(name);
+#if QT_VERSION >= QT_VERSION_CHECK(5, 6, 0)
+    double dpr = !kpxcApp->testAttribute(Qt::AA_UseHighDpiPixmaps) ? 1.0 : painter->device()->devicePixelRatioF();
+#else
+    double dpr = !kpxcApp->testAttribute(Qt::AA_UseHighDpiPixmaps) ? 1.0 : painter->device()->devicePixelRatio();
+#endif
+    QSize pixmapSize = rect.size() * dpr;
 
-    if (!icon.isNull() && !overrideColor.isValid()) {
-        return icon;
+    painter->save();
+    painter->drawPixmap(rect, m_baseIcon.pixmap(pixmapSize, mode, state));
+
+    if (getMainWindow()) {
+        QPalette palette = getMainWindow()->palette();
+        painter->setCompositionMode(QPainter::CompositionMode_SourceAtop);
+
+        if (mode == QIcon::Active) {
+            painter->fillRect(rect, palette.color(QPalette::Active, QPalette::ButtonText));
+        } else if (mode == QIcon::Selected) {
+            painter->fillRect(rect, palette.color(QPalette::Active, QPalette::HighlightedText));
+        } else if (mode == QIcon::Disabled) {
+            painter->fillRect(rect, palette.color(QPalette::Disabled, QPalette::WindowText));
+        } else {
+            painter->fillRect(rect, palette.color(QPalette::Normal, QPalette::WindowText));
+        }
     }
+    painter->restore();
+}
+
+QPixmap AdaptiveIconEngine::pixmap(const QSize& size, QIcon::Mode mode, QIcon::State state)
+{
+    QImage img(size, QImage::Format_ARGB32_Premultiplied);
+    img.fill(0);
+    QPainter painter(&img);
+    paint(&painter, QRect(0, 0, size.width(), size.height()), mode, state);
+    return QPixmap::fromImage(img, Qt::NoFormatConversion);
+}
 
+QIconEngine* AdaptiveIconEngine::clone() const
+{
+    return new AdaptiveIconEngine(m_baseIcon);
+}
+
+QIcon Icons::icon(const QString& name, bool recolor, const QColor& overrideColor)
+{
+#ifdef Q_OS_LINUX
     // Resetting the application theme name before calling QIcon::fromTheme() is required for hacky
     // QPA platform themes such as qt5ct, which randomly mess with the configured icon theme.
     // If we do not reset the theme name here, it will become empty at some point, causing
@@ -94,44 +169,25 @@ QIcon Icons::icon(const QString& name, bool recolor, const QColor& overrideColor
     // See issue #4963: https://github.com/keepassxreboot/keepassxc/issues/4963
     // and qt5ct issue #80: https://sourceforge.net/p/qt5ct/tickets/80/
     QIcon::setThemeName("application");
+#endif
 
-    icon = QIcon::fromTheme(name);
-    if (getMainWindow() && recolor) {
-        const QRect rect(0, 0, 48, 48);
-        QImage img = icon.pixmap(rect.width(), rect.height()).toImage();
-        img = img.convertToFormat(QImage::Format_ARGB32_Premultiplied);
-        icon = {};
-
-        QPainter painter(&img);
-        painter.setCompositionMode(QPainter::CompositionMode_SourceAtop);
-
-        if (!overrideColor.isValid()) {
-            QPalette palette = getMainWindow()->palette();
-            painter.fillRect(rect, palette.color(QPalette::Normal, QPalette::WindowText));
-            icon.addPixmap(QPixmap::fromImage(img), QIcon::Normal);
-
-            painter.fillRect(rect, palette.color(QPalette::Active, QPalette::ButtonText));
-            icon.addPixmap(QPixmap::fromImage(img), QIcon::Active);
-
-            painter.fillRect(rect, palette.color(QPalette::Active, QPalette::HighlightedText));
-            icon.addPixmap(QPixmap::fromImage(img), QIcon::Selected);
+    QString cacheName =
+        QString("%1:%2:%3").arg(recolor ? "1" : "0", overrideColor.isValid() ? overrideColor.name() : "#", name);
+    QIcon icon = m_iconCache.value(cacheName);
 
-            painter.fillRect(rect, palette.color(QPalette::Disabled, QPalette::WindowText));
-            icon.addPixmap(QPixmap::fromImage(img), QIcon::Disabled);
-        } else {
-            painter.fillRect(rect, overrideColor);
-            icon.addPixmap(QPixmap::fromImage(img), QIcon::Normal);
-        }
+    if (!icon.isNull() && !overrideColor.isValid()) {
+        return icon;
+    }
 
+    icon = QIcon::fromTheme(name);
+    if (recolor) {
+        icon = QIcon(new AdaptiveIconEngine(icon));
 #if QT_VERSION >= QT_VERSION_CHECK(5, 6, 0)
         icon.setIsMask(true);
 #endif
     }
 
-    if (!overrideColor.isValid()) {
-        m_iconCache.insert(name, icon);
-    }
-
+    m_iconCache.insert(cacheName, icon);
     return icon;
 }
 
@@ -161,10 +217,6 @@ QIcon Icons::onOffIcon(const QString& name, bool recolor)
     return icon;
 }
 
-Icons::Icons()
-{
-}
-
 Icons* Icons::instance()
 {
     if (!m_instance) {

src/gui/Icons.h

@@ -28,7 +28,7 @@ class Icons
 {
 public:
     QIcon applicationIcon();
-    QIcon trayIcon();
+    QIcon trayIcon(QString style = "unlocked");
     QIcon trayIconLocked();
     QIcon trayIconUnlocked();
     QString trayIconAppearance() const;

src/gui/MainWindow.cpp

@@ -40,6 +40,7 @@
 #include "gui/Icons.h"
 #include "gui/MessageBox.h"
 #include "gui/SearchWidget.h"
+#include "gui/osutils/OSUtils.h"
 #include "keys/CompositeKey.h"
 #include "keys/FileKey.h"
 #include "keys/PasswordKey.h"
@@ -503,6 +504,8 @@ MainWindow::MainWindow()
     connect(m_ui->actionOnlineHelp, SIGNAL(triggered()), SLOT(openOnlineHelp()));
     connect(m_ui->actionKeyboardShortcuts, SIGNAL(triggered()), SLOT(openKeyboardShortcuts()));
 
+    connect(osUtils, &OSUtilsBase::statusbarThemeChanged, this, &MainWindow::updateTrayIcon);
+
 #if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     // Install event filter for empty-area drag
     auto* eventFilter = new MainWindowEventFilter(this);
@@ -599,10 +602,10 @@ MainWindow::MainWindow()
     }
 #endif
 
-    QObject::connect(qApp, SIGNAL(anotherInstanceStarted()), this, SLOT(bringToFront()));
-    QObject::connect(qApp, SIGNAL(applicationActivated()), this, SLOT(bringToFront()));
-    QObject::connect(qApp, SIGNAL(openFile(QString)), this, SLOT(openDatabase(QString)));
-    QObject::connect(qApp, SIGNAL(quitSignalReceived()), this, SLOT(appExit()), Qt::DirectConnection);
+    connect(qApp, SIGNAL(anotherInstanceStarted()), this, SLOT(bringToFront()));
+    connect(qApp, SIGNAL(applicationActivated()), this, SLOT(bringToFront()));
+    connect(qApp, SIGNAL(openFile(QString)), this, SLOT(openDatabase(QString)));
+    connect(qApp, SIGNAL(quitSignalReceived()), this, SLOT(appExit()), Qt::DirectConnection);
 
     restoreConfigState();
 }
@@ -1757,8 +1760,10 @@ void MainWindow::initViewMenu()
 
     connect(themeActions, &QActionGroup::triggered, this, [this, theme](QAction* action) {
         config()->set(Config::GUI_ApplicationTheme, action->data());
-        if (action->data() != theme) {
+        if ((action->data() == "classic" || theme == "classic") && action->data() != theme) {
             restartApp(tr("You must restart the application to apply this setting. Would you like to restart now?"));
+        } else {
+            kpxcApp->applyTheme();
         }
     });
 

src/gui/osutils/OSUtilsBase.h

@@ -35,6 +35,11 @@ class OSUtilsBase : public QObject
      */
     virtual bool isDarkMode() const = 0;
 
+    /**
+     * @return OS task / menu bar is dark.
+     */
+    virtual bool isStatusBarDark() const = 0;
+
     /**
      * @return KeePassXC set to launch at system startup (autostart).
      */
@@ -61,6 +66,16 @@ class OSUtilsBase : public QObject
 signals:
     void globalShortcutTriggered(const QString& name);
 
+    /**
+     * Indicates platform UI theme change (light mode to dark mode).
+     */
+    void interfaceThemeChanged();
+
+    /*
+     * Indicates a change in the tray / statusbar theme.
+     */
+    void statusbarThemeChanged();
+
 protected:
     explicit OSUtilsBase(QObject* parent = nullptr);
     virtual ~OSUtilsBase();

src/gui/osutils/macutils/AppKit.h

@@ -20,6 +20,7 @@
 #define KEEPASSX_APPKIT_H
 
 #include <QObject>
+#include <QColor>
 #include <unistd.h>
 
 class AppKit : public QObject
@@ -37,12 +38,14 @@ class AppKit : public QObject
     bool hideProcess(pid_t pid);
     bool isHidden(pid_t pid);
     bool isDarkMode();
+    bool isStatusBarDark();
     bool enableAccessibility();
     bool enableScreenRecording();
     void toggleForegroundApp(bool foreground);
 
 signals:
     void lockDatabases();
+    void interfaceThemeChanged();
 
 private:
     void* self;