From 4a5e7af9a477a59bb0274c132d090d80950b79d4 Mon Sep 17 00:00:00 2001
From: Adriaan de Groot <groot@kde.org>
Date: Tue, 10 Oct 2023 23:24:12 +0200
Subject: [PATCH] libcalamaresui: support Qt6 QMLViewStep

---
 src/libcalamaresui/viewpages/QmlViewStep.cpp | 34 ++++++++++++++++----
 src/libcalamaresui/viewpages/QmlViewStep.h   | 10 +++++-
 2 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/src/libcalamaresui/viewpages/QmlViewStep.cpp b/src/libcalamaresui/viewpages/QmlViewStep.cpp
index 2af237c43..d96e65eaf 100644
--- a/src/libcalamaresui/viewpages/QmlViewStep.cpp
+++ b/src/libcalamaresui/viewpages/QmlViewStep.cpp
@@ -24,7 +24,12 @@
 #include <QQmlContext>
 #include <QQmlEngine>
 #include <QQuickItem>
+#if QT_VERSION >= QT_VERSION_CHECK( 6, 0, 0 )
+#include <QQuickWindow>
+#else
 #include <QQuickWidget>
+#endif
+
 #include <QVBoxLayout>
 #include <QWidget>
 
@@ -66,16 +71,22 @@ QmlViewStep::QmlViewStep( QObject* parent )
     : ViewStep( parent )
     , m_widget( new QWidget )
     , m_spinner( new WaitingWidget( tr( "Loading ..." ) ) )
-    , m_qmlWidget( new QQuickWidget )
 {
     Calamares::registerQmlModels();
 
+#if QT_VERSION >= QT_VERSION_CHECK( 6, 0, 0 )
+    m_qmlEngine = new QQmlEngine( this );
+#else
+    m_qmlWidget = new QQuickWidget;
+    m_qmlWidget->setResizeMode( QQuickWidget::SizeRootObjectToView );
+    m_qmlWidget->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Expanding );
+    m_qmlEngine = m_qmlWidget->engine();
+#endif
+
     QVBoxLayout* layout = new QVBoxLayout( m_widget );
     layout->addWidget( m_spinner );
 
-    m_qmlWidget->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Expanding );
-    m_qmlWidget->setResizeMode( QQuickWidget::SizeRootObjectToView );
-    m_qmlWidget->engine()->addImportPath( Calamares::qmlModulesDir().absolutePath() );
+    m_qmlEngine->addImportPath( Calamares::qmlModulesDir().absolutePath() );
 
     // QML Loading starts when the configuration for the module is set.
 }
@@ -181,11 +192,20 @@ QmlViewStep::loadComplete()
         }
         else
         {
+#if QT_VERSION >= QT_VERSION_CHECK( 6, 0, 0 )
+            auto* quick = new QQuickWindow;
+            auto* root = quick->contentItem();
+            m_qmlObject->setParentItem( root );
+            m_qmlObject->bindableWidth().setBinding( [ = ]() { return root->width(); } );
+            m_qmlObject->bindableHeight().setBinding( [ = ]() { return root->height(); } );
+            m_qmlWidget = QWidget::createWindowContainer( quick, m_widget );
+#else
             // setContent() is public API, but not documented publicly.
             // It is marked \internal in the Qt sources, but does exactly
             // what is needed: sets up visual parent by replacing the root
             // item, and handling resizes.
             m_qmlWidget->setContent( QUrl( m_qmlFileName ), m_qmlComponent, m_qmlObject );
+#endif
             showQml();
         }
     }
@@ -241,8 +261,8 @@ QmlViewStep::setConfigurationMap( const QVariantMap& configurationMap )
         }
 
         cDebug() << "QmlViewStep" << moduleInstanceKey() << "loading" << m_qmlFileName;
-        m_qmlComponent = new QQmlComponent(
-            m_qmlWidget->engine(), QUrl( m_qmlFileName ), QQmlComponent::CompilationMode::Asynchronous );
+        m_qmlComponent
+            = new QQmlComponent( m_qmlEngine, QUrl( m_qmlFileName ), QQmlComponent::CompilationMode::Asynchronous );
         connect( m_qmlComponent, &QQmlComponent::statusChanged, this, &QmlViewStep::loadComplete );
         if ( m_qmlComponent->status() == QQmlComponent::Error )
         {
@@ -275,7 +295,7 @@ QmlViewStep::getConfig()
 void
 QmlViewStep::setContextProperty( const char* name, QObject* property )
 {
-    m_qmlWidget->engine()->rootContext()->setContextProperty( name, property );
+    m_qmlEngine->rootContext()->setContextProperty( name, property );
 }
 
 }  // namespace Calamares
diff --git a/src/libcalamaresui/viewpages/QmlViewStep.h b/src/libcalamaresui/viewpages/QmlViewStep.h
index eed1003ce..0c36243e6 100644
--- a/src/libcalamaresui/viewpages/QmlViewStep.h
+++ b/src/libcalamaresui/viewpages/QmlViewStep.h
@@ -14,6 +14,7 @@
 #include "viewpages/ViewStep.h"
 
 class QQmlComponent;
+class QQmlEngine;
 class QQuickItem;
 class QQuickWidget;
 class WaitingWidget;
@@ -109,7 +110,14 @@ private:
 
     QWidget* m_widget = nullptr;
     WaitingWidget* m_spinner = nullptr;
-    QQuickWidget* m_qmlWidget = nullptr;
+
+#if QT_VERSION >= QT_VERSION_CHECK( 6, 0, 0 )
+    QWidget* m_qmlWidget = nullptr;  // Qt6: container for QQuickWindow
+#else
+    QQuickWidget * m_qmlWidget = nullptr;
+#endif
+
+    QQmlEngine* m_qmlEngine = nullptr;  // Qt5: points to QuickWidget engine, Qt6: separate engine
     QQmlComponent* m_qmlComponent = nullptr;
     QQuickItem* m_qmlObject = nullptr;
 };