QmlDesigner: Cache last image in 3D view and add busy indicator

This patch caches the last image from a document/model.
The result ist that when reopening a file in the 3D editor
the user sees immediately something.
Since the view is not interactive, yet, we show a busy indicator
until the view is fully initialized.

Change-Id: I26c8b0ea69f98ceb41580624c51d48d1e633ab80
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

share/qtcreator/qmldesigner/misc/BusyIndicator.qml

@@ -0,0 +1,86 @@
+/****************************************************************************
+**
+** Copyright (C) 2022 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+import QtQuick
+import QtQuick.Controls
+
+BusyIndicator {
+    id: control
+
+    contentItem: Item {
+        implicitWidth: 64
+        implicitHeight: 64
+
+        Item {
+            id: item
+            anchors.centerIn: parent
+            width: 64
+            height: 64
+            opacity: control.running ? 1 : 0
+
+            Behavior on opacity {
+                OpacityAnimator {
+                    duration: 250
+                }
+            }
+
+            RotationAnimator {
+                target: item
+                running: control.visible && control.running
+                from: 0
+                to: 360
+                loops: Animation.Infinite
+                duration: 2000
+            }
+
+            Repeater {
+                id: repeater
+                model: 6
+
+                Rectangle {
+                    id: delegate
+                    anchors.centerIn: parent
+                    implicitWidth: 10
+                    implicitHeight: 10
+                    radius: 5
+                    color: "#2aafd3"
+
+                    required property int index
+
+                    transform: [
+                        Translate {
+                            y: -Math.min(item.width, item.height) * 0.5 + 5
+                        },
+                        Rotation {
+                            angle: delegate.index / repeater.count * 360
+                            origin.x: 5
+                            origin.y: 5
+                        }
+                    ]
+                }
+            }
+        }
+    }
+}

src/plugins/qmldesigner/components/edit3d/edit3dcanvas.cpp

@@ -30,21 +30,43 @@
 #include "nodehints.h"
 #include "qmlvisualnode.h"
 
+#include <utils/qtcassert.h>
+
+#include <coreplugin/icore.h>
+
 #include <qmldesignerplugin.h>
 #include <qmldesignerconstants.h>
 
-#include <QtCore/qmimedata.h>
+#include <QFileInfo>
 #include <QPainter>
+#include <QQuickWidget>
+#include <QtCore/qmimedata.h>
 
 namespace QmlDesigner {
 
+static QQuickWidget *createBusyIndicator(QWidget *p)
+{
+    auto widget = new QQuickWidget(p);
+
+    const QString source = Core::ICore::resourcePath("qmldesigner/misc/BusyIndicator.qml").toString();
+    QTC_ASSERT(QFileInfo::exists(source), return widget);
+    widget->setSource(QUrl::fromLocalFile(source));
+    widget->setFixedSize(64, 64);
+    widget->setAttribute(Qt::WA_AlwaysStackOnTop);
+    widget->setClearColor(Qt::transparent);
+    widget->setResizeMode(QQuickWidget::SizeRootObjectToView);
+    return widget;
+}
+
 Edit3DCanvas::Edit3DCanvas(Edit3DWidget *parent)
-    : QWidget(parent),
+    : QWidget(parent)
-    m_parent(parent)
+    , m_parent(parent)
+    , m_busyIndicator(createBusyIndicator(this))
 {
     setMouseTracking(true);
     setAcceptDrops(true);
     setFocusPolicy(Qt::ClickFocus);
+    m_busyIndicator->show();
 }
 
 void Edit3DCanvas::updateRenderImage(const QImage &img)
@@ -58,6 +80,21 @@ void Edit3DCanvas::updateActiveScene(qint32 activeScene)
     m_activeScene = activeScene;
 }
 
+QImage QmlDesigner::Edit3DCanvas::renderImage() const
+{
+    return m_image;
+}
+
+void Edit3DCanvas::setOpacity(qreal opacity)
+{
+    m_opacity = opacity;
+}
+
+QWidget *Edit3DCanvas::busyIndicator() const
+{
+    return m_busyIndicator;
+}
+
 void Edit3DCanvas::mousePressEvent(QMouseEvent *e)
 {
     m_parent->view()->sendInputEvent(e);
@@ -108,11 +145,17 @@ void Edit3DCanvas::paintEvent(QPaintEvent *e)
 
     QPainter painter(this);
 
+    if (m_opacity < 1.0) {
+        painter.fillRect(rect(), Qt::black);
+        painter.setOpacity(m_opacity);
+    }
+
     painter.drawImage(rect(), m_image, QRect(0, 0, m_image.width(), m_image.height()));
 }
 
 void Edit3DCanvas::resizeEvent(QResizeEvent *e)
 {
+    positionBusyInidicator();
     m_parent->view()->edit3DViewResized(e->size());
 }
 
@@ -161,4 +204,9 @@ void Edit3DCanvas::focusInEvent(QFocusEvent *focusEvent)
     QWidget::focusInEvent(focusEvent);
 }
 
+void Edit3DCanvas::positionBusyInidicator()
+{
+    m_busyIndicator->move(width() / 2 - 32, height() / 2 - 32);
+}
+
 }

src/plugins/qmldesigner/components/edit3d/edit3dcanvas.h

@@ -45,8 +45,10 @@ public:
 
     void updateRenderImage(const QImage &img);
     void updateActiveScene(qint32 activeScene);
-
     qint32 activeScene() const { return m_activeScene; }
+    QImage renderImage() const;
+    void setOpacity(qreal opacity);
+    QWidget *busyIndicator() const;
 
 protected:
     void mousePressEvent(QMouseEvent *e) override;
@@ -64,11 +66,15 @@ protected:
     void focusInEvent(QFocusEvent *focusEvent) override;
 
 private:
+    void positionBusyInidicator();
+
     QPointer<Edit3DWidget> m_parent;
     QImage m_image;
     qint32 m_activeScene = -1;
     ItemLibraryEntry m_itemLibraryEntry;
     QElapsedTimer m_usageTimer;
+    qreal m_opacity = 1.0;
+    QWidget *m_busyIndicator = nullptr;
 };
 
 } // namespace QmlDesigner

src/plugins/qmldesigner/components/edit3d/edit3dview.cpp

@@ -110,6 +110,10 @@ void Edit3DView::renderImage3DChanged(const QImage &img)
     // Notify puppet to resize if received image wasn't correct size
     if (img.size() != canvasSize())
         edit3DViewResized(canvasSize());
+    if (edit3DWidget()->canvas()->busyIndicator()->isVisible()) {
+        edit3DWidget()->canvas()->setOpacity(1.0);
+        edit3DWidget()->canvas()->busyIndicator()->hide();
+    }
 }
 
 void Edit3DView::updateActiveScene3D(const QVariantMap &sceneState)
@@ -195,13 +199,19 @@ void Edit3DView::modelAttached(Model *model)
     AbstractView::modelAttached(model);
 
     checkImports();
+    auto cachedImage = m_canvasCache.take(model);
+    if (cachedImage) {
+        edit3DWidget()->canvas()->updateRenderImage(*cachedImage);
+        edit3DWidget()->canvas()->setOpacity(0.5);
+    }
+
+    edit3DWidget()->canvas()->busyIndicator()->show();
 }
 
 void Edit3DView::modelAboutToBeDetached(Model *model)
 {
-    Q_UNUSED(model)
-
     // Hide the canvas when model is detached (i.e. changing documents)
+    m_canvasCache.insert(model, edit3DWidget()->canvas()->renderImage());
     edit3DWidget()->showCanvas(false);
 
     AbstractView::modelAboutToBeDetached(model);

src/plugins/qmldesigner/components/edit3d/edit3dview.h

@@ -27,6 +27,8 @@
 #include "view3dactioncommand.h"
 #include "seekerslider.h"
 
+#include <modelcache.h>
+
 #include <abstractview.h>
 #include <QtGui/qevent.h>
 #include <QtGui/qimage.h>
@@ -107,6 +109,7 @@ private:
     Edit3DAction *m_visibilityTogglesAction = nullptr;
     SeekerSlider *m_seeker = nullptr;
     int particlemode;
+    ModelCache<QImage> m_canvasCache;
 };
 
 } // namespace QmlDesigner