QmlDesigner: Add StudioQuickWidget

This makes it easy to share the QQmlEngine between different
QQuickWidgets.
All StudioQuickWidgets share the same engine.

Change-Id: I2b370a45a14fdc143e161e2aca62b45aa0d91da9
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/plugins/qmldesignerbase/CMakeLists.txt

@@ -1,5 +1,5 @@
 add_qtc_plugin(QmlDesignerBase
-  DEPENDS Qt::Core
+  DEPENDS Qt::Core Qt::QuickWidgets
   PLUGIN_DEPENDS Core ProjectExplorer QtSupport
   SOURCES
     qmldesignerbase_global.h
@@ -12,4 +12,5 @@ extend_qtc_plugin(QmlDesignerBase
   SOURCES
     designersettings.cpp designersettings.h
     qmlpuppetpaths.cpp qmlpuppetpaths.h
+    studioquickwidget.cpp studioquickwidget.h
 )

src/plugins/qmldesignerbase/utils/qmlpuppetpaths.h

@@ -1,6 +1,8 @@
 // Copyright (C) 2023 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
 
+#pragma once
+
 #include "../qmldesignerbase_global.h"
 
 #include <utils/filepath.h>

src/plugins/qmldesignerbase/utils/studioquickwidget.cpp

@@ -0,0 +1,60 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#include "studioquickwidget.h"
+
+#include <QVBoxLayout>
+#include <QtQml/QQmlEngine>
+
+QQmlEngine *s_engine = nullptr;
+
+StudioQuickWidget::StudioQuickWidget(QWidget *parent)
+    : QWidget{parent}
+{
+    if (!s_engine)
+        s_engine = new QQmlEngine;
+
+    m_quickWidget = new QQuickWidget(s_engine, this);
+
+    QVBoxLayout *layout = new QVBoxLayout(this);
+    setLayout(layout);
+    layout->setContentsMargins(0, 0, 0, 0);
+    layout->addWidget(m_quickWidget);
+}
+
+QQmlEngine *StudioQuickWidget::engine() const
+{
+    return m_quickWidget->engine();
+}
+
+QQmlContext *StudioQuickWidget::rootContext() const
+{
+    return m_quickWidget->rootContext();
+}
+
+QQuickItem *StudioQuickWidget::rootObject() const
+{
+    return m_quickWidget->rootObject();
+}
+
+void StudioQuickWidget::setResizeMode(QQuickWidget::ResizeMode mode)
+{
+    m_quickWidget->setResizeMode(mode);
+}
+
+void StudioQuickWidget::setSource(const QUrl &url)
+{
+    m_quickWidget->setSource(url);
+}
+
+void StudioQuickWidget::refresh() {}
+
+void StudioQuickWidget::setClearColor(const QColor &color)
+{
+    m_quickWidget->setClearColor(color);
+}
+
+QList<QQmlError> StudioQuickWidget::errors() const
+{
+    return m_quickWidget->errors();
+}

src/plugins/qmldesignerbase/utils/studioquickwidget.h

@@ -0,0 +1,34 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#pragma once
+
+#include "../qmldesignerbase_global.h"
+
+#include <QObject>
+#include <QtQuickWidgets/QQuickWidget>
+
+class QMLDESIGNERBASE_EXPORT StudioQuickWidget : public QWidget
+{
+    Q_OBJECT
+public:
+    explicit StudioQuickWidget(QWidget *parent = nullptr);
+
+    QQmlEngine *engine() const;
+    QQmlContext *rootContext() const;
+
+    QQuickItem *rootObject() const;
+
+    void setResizeMode(QQuickWidget::ResizeMode mode);
+
+    void setSource(const QUrl &url);
+
+    void refresh();
+
+    void setClearColor(const QColor &color);
+
+    QList<QQmlError> errors() const;
+
+private:
+    QQuickWidget *m_quickWidget = nullptr;
+};