From 618c94f2228561f74ca75b2c5bcc17ee5d9a107d Mon Sep 17 00:00:00 2001
From: Heikkinen Miikka <miikka.heikkinen@digia.com>
Date: Mon, 13 May 2013 11:24:30 +0300
Subject: Fix quick2 support with multithreaded scenegraph rendering.
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Change-Id: Ia9bf896e1fb2684e4272547704924e5035f78268
Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>
---
 plugins/declarative/declarativechart.cpp | 46 +++++++++++++++++++++++++++++---
 plugins/declarative/declarativechart.h   |  6 +++++
 2 files changed, 49 insertions(+), 3 deletions(-)

(limited to 'plugins')

diff --git a/plugins/declarative/declarativechart.cpp b/plugins/declarative/declarativechart.cpp
index 2d2c9528..e692ad43 100644
--- a/plugins/declarative/declarativechart.cpp
+++ b/plugins/declarative/declarativechart.cpp
@@ -45,6 +45,7 @@
 #include <QGraphicsSceneMouseEvent>
 #include <QGraphicsSceneHoverEvent>
 #include <QApplication>
+#include <QTimer>
 #endif
 
 QTCOMMERCIALCHART_BEGIN_NAMESPACE
@@ -263,6 +264,8 @@ DeclarativeChart::DeclarativeChart(QChart::ChartType type, QDECLARATIVE_ITEM *pa
 void DeclarativeChart::initChart(QChart::ChartType type)
 {
 #ifdef CHARTS_FOR_QUICK2
+    m_currentSceneImage = 0;
+
     if (type == QChart::ChartTypePolar)
         m_chart = new QPolarChart();
     else
@@ -272,7 +275,7 @@ void DeclarativeChart::initChart(QChart::ChartType type)
     m_scene->addItem(m_chart);
 
     setAntialiasing(QQuickItem::antialiasing());
-    connect(m_scene, SIGNAL(changed(QList<QRectF>)), this, SLOT(update()));
+    connect(m_scene, SIGNAL(changed(QList<QRectF>)), this, SLOT(sceneChanged(QList<QRectF>)));
     connect(this, SIGNAL(antialiasingChanged(bool)), this, SLOT(handleAntialiasingChanged(bool)));
 
     setAcceptedMouseButtons(Qt::AllButtons);
@@ -314,6 +317,12 @@ void DeclarativeChart::changeMinimumMargins(int top, int bottom, int left, int r
 DeclarativeChart::~DeclarativeChart()
 {
     delete m_chart;
+#ifdef CHARTS_FOR_QUICK2
+    m_sceneImageLock.lock();
+    delete m_currentSceneImage;
+    m_currentSceneImage = 0;
+    m_sceneImageLock.unlock();
+#endif
 }
 
 void DeclarativeChart::childEvent(QChildEvent *event)
@@ -416,10 +425,41 @@ void DeclarativeChart::geometryChanged(const QRectF &newGeometry, const QRectF &
 }
 
 #ifdef CHARTS_FOR_QUICK2
+void DeclarativeChart::sceneChanged(QList<QRectF> region)
+{
+    Q_UNUSED(region);
+
+    if (!m_updatePending) {
+        m_updatePending = true;
+        // Do async render to avoid some unnecessary renders.
+        QTimer::singleShot(0, this, SLOT(renderScene()));
+    }
+}
+
+void DeclarativeChart::renderScene()
+{
+    m_updatePending = false;
+    m_sceneImageLock.lock();
+    delete m_currentSceneImage;
+    m_currentSceneImage = new QImage(m_chart->size().toSize(), QImage::Format_ARGB32);
+    m_currentSceneImage->fill(Qt::transparent);
+    QPainter painter(m_currentSceneImage);
+    QRect renderRect(QPoint(0, 0), m_chart->size().toSize());
+    m_scene->render(&painter, renderRect, renderRect);
+    m_sceneImageLock.unlock();
+
+    update();
+}
+
 void DeclarativeChart::paint(QPainter *painter)
 {
-    QRectF renderRect(QPointF(0, 0), m_chart->size());
-    m_scene->render(painter, renderRect, renderRect);
+    m_sceneImageLock.lock();
+    if (m_currentSceneImage) {
+        QRect imageRect(QPoint(0, 0), m_currentSceneImage->size());
+        QRect itemRect(QPoint(0, 0), QSize(width(), height()));
+        painter->drawImage(itemRect, *m_currentSceneImage, imageRect);
+    }
+    m_sceneImageLock.unlock();
 }
 
 void DeclarativeChart::mousePressEvent(QMouseEvent *event)
diff --git a/plugins/declarative/declarativechart.h b/plugins/declarative/declarativechart.h
index f0e24cb7..139e6290 100644
--- a/plugins/declarative/declarativechart.h
+++ b/plugins/declarative/declarativechart.h
@@ -28,6 +28,7 @@
 #include <QtQuick/QQuickItem>
 #include <QtQuick/QQuickPaintedItem>
 #include <QtWidgets/QGraphicsScene>
+#include <QtCore/QMutex>
 #else
 #include <QtDeclarative/QDeclarativeItem>
 #endif
@@ -118,6 +119,8 @@ protected:
     void hoverMoveEvent(QHoverEvent *event);
 private Q_SLOTS:
     void handleAntialiasingChanged(bool enable);
+    void sceneChanged(QList<QRectF> region);
+    void renderScene();
 #endif
 
 public:
@@ -212,6 +215,9 @@ private:
     QPoint m_lastMouseMoveScreenPoint;
     Qt::MouseButton m_mousePressButton;
     Qt::MouseButtons m_mousePressButtons;
+    QMutex m_sceneImageLock;
+    QImage *m_currentSceneImage;
+    bool m_updatePending;
 #endif
     DeclarativeMargins *m_margins;
 };
-- 
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