fix: fix default palette on the KDE6 flatpak runtime

Author: timschneeb

src/src.pro

@@ -23,7 +23,8 @@ UI_DEBUG: DEFINES += UI_DEBUG
 DEBUG_FPE: DEFINES += DEBUG_FPE
 DEBUG_ASAN: CONFIG += sanitizer sanitize_address
 USE_PULSEAUDIO: DEFINES += USE_PULSEAUDIO
-USE_PORTALS: DEFINES += USE_PORTALS
+FLATPAK: DEFINES += USE_PORTALS
+FLATPAK: DEFINES += IS_FLATPAK
 HEADLESS: DEFINES += HEADLESS
 NO_CRASH_HANDLER: DEFINES += NO_CRASH_HANDLER
 

src/utils/StyleHelper.cpp

@@ -44,7 +44,11 @@ void StyleHelper::SetStyle()
 	else
 	{
 		loadIcons(false);
+#ifndef IS_FLATPAK
 		QApplication::setPalette(m_host->style()->standardPalette());
+#else
+		QApplication::setPalette(getDefaultLightPalette());
+#endif
 	}
 
     QFile f(":/styles/default.qss");
@@ -99,6 +103,58 @@ void StyleHelper::setPalette(const ColorStyle &s)
                         })").arg(s.disabled.name()));
 }
 
+QPalette StyleHelper::getDefaultLightPalette() {
+	const bool darkAppearance = false;
+    const QColor windowText = darkAppearance ? QColor(240, 240, 240) : Qt::black;
+    const QColor backGround = darkAppearance ? QColor(50, 50, 50) : QColor(239, 239, 239);
+    const QColor light = backGround.lighter(150);
+    const QColor mid = (backGround.darker(130));
+    const QColor midLight = mid.lighter(110);
+    const QColor base = darkAppearance ? backGround.darker(140) : Qt::white;
+    const QColor disabledBase(backGround);
+    const QColor dark = backGround.darker(150);
+    const QColor darkDisabled = QColor(209, 209, 209).darker(110);
+    const QColor text = darkAppearance ? windowText : Qt::black;
+    const QColor highlight = QColor(48, 140, 198);
+    const QColor hightlightedText = darkAppearance ? windowText : Qt::white;
+    const QColor disabledText = darkAppearance ? QColor(130, 130, 130) : QColor(190, 190, 190);
+    const QColor button = backGround;
+    const QColor shadow = dark.darker(135);
+    const QColor disabledShadow = shadow.lighter(150);
+    const QColor disabledHighlight(145, 145, 145);
+    QColor placeholder = text;
+    placeholder.setAlpha(128);
+
+    QPalette fusionPalette(windowText, backGround, light, dark, mid, text, base);
+    fusionPalette.setBrush(QPalette::Midlight, midLight);
+    fusionPalette.setBrush(QPalette::Button, button);
+    fusionPalette.setBrush(QPalette::Shadow, shadow);
+    fusionPalette.setBrush(QPalette::HighlightedText, hightlightedText);
+
+    fusionPalette.setBrush(QPalette::Disabled, QPalette::Text, disabledText);
+    fusionPalette.setBrush(QPalette::Disabled, QPalette::WindowText, disabledText);
+    fusionPalette.setBrush(QPalette::Disabled, QPalette::ButtonText, disabledText);
+    fusionPalette.setBrush(QPalette::Disabled, QPalette::Base, disabledBase);
+    fusionPalette.setBrush(QPalette::Disabled, QPalette::Dark, darkDisabled);
+    fusionPalette.setBrush(QPalette::Disabled, QPalette::Shadow, disabledShadow);
+
+    fusionPalette.setBrush(QPalette::Active, QPalette::Highlight, highlight);
+    fusionPalette.setBrush(QPalette::Inactive, QPalette::Highlight, highlight);
+    fusionPalette.setBrush(QPalette::Disabled, QPalette::Highlight, disabledHighlight);
+
+    fusionPalette.setBrush(QPalette::Active, QPalette::Accent, highlight);
+    fusionPalette.setBrush(QPalette::Inactive, QPalette::Accent, highlight);
+    fusionPalette.setBrush(QPalette::Disabled, QPalette::Accent, disabledHighlight);
+
+    fusionPalette.setBrush(QPalette::PlaceholderText, placeholder);
+
+    // Use a more legible light blue on dark backgrounds than the default Qt::blue.
+    if (darkAppearance)
+        fusionPalette.setBrush(QPalette::Link, highlight);
+
+    return fusionPalette;
+}
+
 void StyleHelper::loadIcons(bool white)
 {
     emit iconColorChanged(white);

src/utils/StyleHelper.h

@@ -34,6 +34,7 @@ class StyleHelper :
 	int  loadColor(int index,
 	               int rgb_index);
 	void setPalette(const ColorStyle &s);
+	QPalette StyleHelper::getDefaultLightPalette();
 
 private:
 	QObject *m_objhost;