added main window transparency on start

Author: igorkorsukov

CMakeLists.txt

@@ -104,6 +104,7 @@ option(MUE_DOWNLOAD_SOUNDFONT "Download the latest soundfont version as part of
 # === Pack ===
 option(MUE_RUN_LRELEASE "Generate .qm files" ON)
 option(MUE_INSTALL_SOUNDFONT "Install sound font" ON)
+option(MUE_RUN_WINDEPLOYQT "Run windeployqt" ON)
 
 # === Tests ===
 set(MUE_VTEST_MSCORE_REF_BIN "${CMAKE_CURRENT_LIST_DIR}/../MU_ORIGIN/MuseScore/build.debug/install/${INSTALL_SUBDIR}/mscore" CACHE PATH "Path to mscore ref bin")

src/app/CMakeLists.txt

@@ -353,8 +353,8 @@ if (OS_IS_WIN)
         configure_file(${PROJECT_SOURCE_DIR}/buildscripts/packaging/Windows/PortableApps/appinfo.ini.in     ${CMAKE_INSTALL_PREFIX}/../../App/AppInfo/appinfo.ini   @ONLY)
     endif (WIN_PORTABLE)
 
+if (MUE_RUN_WINDEPLOYQT)
     set(deploy_tool_options_arg "--plugindir bin --qmldir ${PROJECT_SOURCE_DIR}")
-
     qt_generate_deploy_qml_app_script(
         TARGET MuseScoreStudio
         OUTPUT_SCRIPT deploy_script
@@ -363,6 +363,7 @@ if (OS_IS_WIN)
     )
 
     install(SCRIPT ${deploy_script})
+endif() # MUE_RUN_WINDEPLOYQT
 
 ###########################################
 # Linux

src/app/internal/guiapp.cpp

@@ -144,9 +144,6 @@ void GuiApp::perform()
     // ====================================================
     // Setup Qml Engine
     // ====================================================
-    //! Needs to be set because we use transparent windows for PopupView.
-    //! Needs to be called before any QQuickWindows are shown.
-    QQuickWindow::setDefaultAlphaBuffer(true);
 
     //! NOTE Adjust GS Api
     //! We can hide this algorithm in GSApiProvider,
@@ -247,6 +244,13 @@ void GuiApp::perform()
             // The main window must be shown at this point so KDDockWidgets can read its size correctly
             // and scale all sizes properly. https://github.com/musescore/MuseScore/issues/21148
             QQuickWindow* w = dynamic_cast<QQuickWindow*>(obj);
+            // but before that, let's make the window transparent,
+            // otherwise the empty window frame will be visible
+            // https://github.com/musescore/MuseScore/issues/29630
+            // Transparency will be removed after the page loads.
+            QQuickWindow::setDefaultAlphaBuffer(true);
+            w->setOpacity(0.01);
+
             w->setVisible(true);
 
             startupScenario()->runAfterSplashScreen();

src/appshell/qml/WindowContent.qml

@@ -39,6 +39,7 @@ DockWindow {
 
     onPageLoaded: {
         interactiveProvider.onPageOpened()
+        window.opacity = 1.0
     }
 
     InteractiveProvider {