From ea4a5a463ded8dd499cede31660e8f5d079df2fe Mon Sep 17 00:00:00 2001
From: Vlad Zahorodnii <vlad.zahorodnii@kde.org>
Date: Sun, 15 Oct 2023 16:41:46 +0300
Subject: [PATCH] Provide compositor opaque hint

Konsole requests alpha channel even when background is opaque. Since the
opaque region is not set, the compositor (kwin) will render windows
beneath konsole because it has no idea what part of konsole is actually
opaque.

This change makes Konsole set the Qt::WA_TranslucentBackground attribute
based on whether opacity is set in the color scheme profile.

If the opacity is 1, the translucent background attribute will be unset
and QtWayland will set an opaque region, which would allow kwin to avoid
repainting windows behind konsole.

If the opacity changes to a value other than 1, the translucent
background flag will be set and QtWayland will unset the opaque region.
---
 src/MainWindow.cpp  | 13 +++++++++++++
 src/MainWindow.h    |  2 ++
 src/ViewManager.cpp |  1 +
 src/ViewManager.h   |  1 +
 4 files changed, 17 insertions(+)

diff --git a/src/MainWindow.cpp b/src/MainWindow.cpp
index f684d6a12..b9fe17165 100644
--- a/src/MainWindow.cpp
+++ b/src/MainWindow.cpp
@@ -92,6 +92,7 @@ MainWindow::MainWindow()
     connect(_viewManager, &Konsole::ViewManager::unplugController, this, &Konsole::MainWindow::disconnectController);
     connect(_viewManager, &Konsole::ViewManager::viewPropertiesChanged, bookmarkHandler(), &Konsole::BookmarkHandler::setViews);
     connect(_viewManager, &Konsole::ViewManager::blurSettingChanged, this, &Konsole::MainWindow::setBlur);
+    connect(_viewManager, &Konsole::ViewManager::translucentBackgroundSettingChanged, this, &Konsole::MainWindow::setTranslucentBackgroundEnabled);
 
     connect(_viewManager, &Konsole::ViewManager::updateWindowIcon, this, &Konsole::MainWindow::updateWindowIcon);
     connect(_viewManager, &Konsole::ViewManager::newViewWithProfileRequest, this, &Konsole::MainWindow::newFromProfile);
@@ -155,6 +156,10 @@ void MainWindow::updateUseTransparency()
     setAttribute(Qt::WA_TranslucentBackground, useTranslucency);
     setAttribute(Qt::WA_NoSystemBackground, false);
     WindowSystemInfo::HAVE_TRANSPARENCY = useTranslucency;
+
+#if QT_VERSION >= QT_VERSION_CHECK(6, 10, 0)
+    windowHandle()->setOpaque(!_translucentBackgroundEnabled);
+#endif
 }
 
 void MainWindow::activationRequest(const QString &xdgActivationToken)
@@ -995,6 +1000,14 @@ void MainWindow::setBlur(bool blur)
     }
 }
 
+void MainWindow::setTranslucentBackgroundEnabled(bool enabled)
+{
+    if (enabled != _translucentBackgroundEnabled) {
+        _translucentBackgroundEnabled = enabled;
+        updateUseTransparency();
+    }
+}
+
 void MainWindow::setMenuBarInitialVisibility(bool showMenuBar)
 {
     _windowArgsMenuBarVisible.enabled = true;
diff --git a/src/MainWindow.h b/src/MainWindow.h
index 990904d65..b968321b6 100644
--- a/src/MainWindow.h
+++ b/src/MainWindow.h
@@ -167,6 +167,7 @@ private Q_SLOTS:
     void profileListChanged(const QList<QAction *> &sessionActions);
     void configureNotifications();
     void setBlur(bool blur);
+    void setTranslucentBackgroundEnabled(bool enabled);
 
     void updateWindowIcon();
     void updateWindowCaption();
@@ -223,6 +224,7 @@ private:
     std::vector<IKonsolePlugin *> _plugins;
     QList<QAction *> _pluginsActions;
     bool _blurEnabled = false;
+    bool _translucentBackgroundEnabled = false;
     bool _firstShowEvent = true;
 
     struct {
diff --git a/src/ViewManager.cpp b/src/ViewManager.cpp
index 617e8cb1e..b4e621f74 100644
--- a/src/ViewManager.cpp
+++ b/src/ViewManager.cpp
@@ -1091,6 +1091,7 @@ void ViewManager::applyProfileToView(TerminalDisplay *view, const Profile::Ptr &
     view->applyProfile(profile);
     Q_EMIT updateWindowIcon();
     Q_EMIT blurSettingChanged(view->colorScheme()->blur());
+    Q_EMIT translucentBackgroundSettingChanged(view->colorScheme()->opacity() != 1.0);
 }
 
 void ViewManager::updateViewsForSession(Session *session)
diff --git a/src/ViewManager.h b/src/ViewManager.h
index 544ad1d57..82b8388ea 100644
--- a/src/ViewManager.h
+++ b/src/ViewManager.h
@@ -228,6 +228,7 @@ Q_SIGNALS:
     void updateWindowIcon();
 
     void blurSettingChanged(bool);
+    void translucentBackgroundSettingChanged(bool);
 
     /** Requests creation of a new view with the default profile. */
     void newViewRequest();