From b485b9ca8983499a55d7e06a3ac3f0ac45a61b99 Mon Sep 17 00:00:00 2001
From: Vlad Zahorodnii <vlad.zahorodnii@kde.org>
Date: Sat, 29 Jan 2022 21:59:33 +0200
Subject: [PATCH 14/19] Make sure QQuickWidget and its offscreen window's
 screens are always in sync

By default, the offscreen window is placed on the primary screen.
However, if the parent widget argument is passed to the QQuickWidget's
constructor, then QQuickWidget's and the offscreen window's screens can
be different and that can create rendering issues, e.g. blurry text if
the primary screen and QQuickWidget's screen have different scale
factors.

Change-Id: I10c62b5635664f943b11828773f14017f198a770
Reviewed-by: David Edmundson <davidedmundson@kde.org>
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>
(cherry picked from commit a2a2734bffa1459639b31fb3f4f83873ba44ab5c)
---
 src/quickwidgets/qquickwidget.cpp | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/src/quickwidgets/qquickwidget.cpp b/src/quickwidgets/qquickwidget.cpp
index 39780f8de3..223d91f579 100644
--- a/src/quickwidgets/qquickwidget.cpp
+++ b/src/quickwidgets/qquickwidget.cpp
@@ -106,6 +106,7 @@ void QQuickWidgetPrivate::init(QQmlEngine* e)
 
     renderControl = new QQuickWidgetRenderControl(q);
     offscreenWindow = new QQuickWindow(*new QQuickOffcreenWindowPrivate(),renderControl);
+    offscreenWindow->setScreen(q->screen());
     offscreenWindow->setTitle(QString::fromLatin1("Offscreen"));
     offscreenWindow->setObjectName(QString::fromLatin1("QQuickOffScreenWindow"));
     // Do not call create() on offscreenWindow.
@@ -901,9 +902,7 @@ void QQuickWidgetPrivate::createContext()
 
         context = new QOpenGLContext;
         context->setFormat(offscreenWindow->requestedFormat());
-        const QWindow *win = q->window()->windowHandle();
-        if (win && win->screen())
-            context->setScreen(win->screen());
+        context->setScreen(q->screen());
         QOpenGLContext *shareContext = qt_gl_global_share_context();
         if (!shareContext)
             shareContext = QWidgetPrivate::get(q->window())->shareContext();
@@ -1520,19 +1519,16 @@ bool QQuickWidget::event(QEvent *e)
         d->handleWindowChange();
         break;
 
-    case QEvent::ScreenChangeInternal:
-        if (QWindow *window = this->window()->windowHandle()) {
-            QScreen *newScreen = window->screen();
-
-            if (d->offscreenWindow)
-                d->offscreenWindow->setScreen(newScreen);
-            if (d->offscreenSurface)
-                d->offscreenSurface->setScreen(newScreen);
+    case QEvent::ScreenChangeInternal: {
+        QScreen *newScreen = screen();
+        if (d->offscreenWindow)
+            d->offscreenWindow->setScreen(newScreen);
+        if (d->offscreenSurface)
+            d->offscreenSurface->setScreen(newScreen);
 #if QT_CONFIG(opengl)
-            if (d->context)
-                d->context->setScreen(newScreen);
+        if (d->context)
+            d->context->setScreen(newScreen);
 #endif
-        }
 
         if (d->useSoftwareRenderer
 #if QT_CONFIG(opengl)
@@ -1545,7 +1541,7 @@ bool QQuickWidget::event(QEvent *e)
             d->render(true);
         }
         break;
-
+    }
     case QEvent::Show:
     case QEvent::Move:
         d->updatePosition();
-- 
2.36.1