Avoid painting while loading in the anomaly demo browser

At load time, loading, layouting and painting are fighting for
the CPU. By skipping painting and layouting, we achieve a better
loading time, and the experience is better.

5 files changed, 72 insertions, 5 deletions

diff --git a/demos/embedded/anomaly/anomaly.pro b/demos/embedded/anomaly/anomaly.pro
index 2871ba7c90..165ce8980b 100644
--- a/demos/embedded/anomaly/anomaly.pro
+++ b/demos/embedded/anomaly/anomaly.pro
@@ -8,7 +8,8 @@ HEADERS += src/BrowserWindow.h \
     src/BookmarksView.h \
     src/flickcharm.h \
     src/ZoomStrip.h \
-    src/ControlStrip.h
+    src/ControlStrip.h \
+    src/webview.h
 SOURCES += src/Main.cpp \
     src/BrowserWindow.cpp \
     src/BrowserView.cpp \
@@ -18,7 +19,8 @@ SOURCES += src/Main.cpp \
     src/BookmarksView.cpp \
     src/flickcharm.cpp \
     src/ZoomStrip.cpp \
-    src/ControlStrip.cpp
+    src/ControlStrip.cpp \
+    src/webview.cpp
 RESOURCES += src/anomaly.qrc
 
 symbian {
diff --git a/demos/embedded/anomaly/src/BrowserView.cpp b/demos/embedded/anomaly/src/BrowserView.cpp
index ab52e81ca8..0945b89d7f 100644
--- a/demos/embedded/anomaly/src/BrowserView.cpp
+++ b/demos/embedded/anomaly/src/BrowserView.cpp
@@ -48,6 +48,7 @@
 #include "ControlStrip.h"
 #include "TitleBar.h"
 #include "flickcharm.h"
+#include "webview.h"
 #include "ZoomStrip.h"
 
 #if defined (Q_OS_SYMBIAN)
@@ -62,7 +63,7 @@ BrowserView::BrowserView(QWidget *parent)
     , m_currentZoom(100)
 {
     m_titleBar = new TitleBar(this);
-    m_webView = new QWebView(this);
+    m_webView = new WebView(this);
     m_zoomStrip = new ZoomStrip(this);
     m_controlStrip = new ControlStrip(this);
 
@@ -95,7 +96,7 @@ void BrowserView::initialize()
     connect(m_webView, SIGNAL(loadFinished(bool)), SLOT(finish(bool)));
     connect(m_webView, SIGNAL(urlChanged(QUrl)), SLOT(updateTitleBar()));
 
-    m_webView->setHtml("Will try to load page soon!");
+    m_webView->setHtml("about:blank");
     m_webView->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
     m_webView->setFocus();
 #ifdef Q_OS_SYMBIAN
diff --git a/demos/embedded/anomaly/src/BrowserView.h b/demos/embedded/anomaly/src/BrowserView.h
index fdc126db79..5ab1dd71e2 100644
--- a/demos/embedded/anomaly/src/BrowserView.h
+++ b/demos/embedded/anomaly/src/BrowserView.h
@@ -49,6 +49,7 @@ class QUrl;
 class QWebView;
 class TitleBar;
 class ControlStrip;
+class WebView;
 class ZoomStrip;
 
 class BrowserView : public QWidget
@@ -81,7 +82,7 @@ protected:
 
 private:
     TitleBar *m_titleBar;
-    QWebView *m_webView;
+    WebView *m_webView;
     ZoomStrip *m_zoomStrip;
     ControlStrip *m_controlStrip;
     int m_progress;
@@ -90,3 +91,4 @@ private:
 };
 
 #endif // BROWSERVIEW_H
+
diff --git a/demos/embedded/anomaly/src/webview.cpp b/demos/embedded/anomaly/src/webview.cpp
new file mode 100644
index 0000000000..d55c68eda1
--- /dev/null
+++ b/demos/embedded/anomaly/src/webview.cpp
@@ -0,0 +1,37 @@
+#include "webview.h"
+
+#include <QPaintEvent>
+
+WebView::WebView(QWidget *parent)
+    : QWebView(parent)
+    , inLoading(false)
+{
+    connect(this, SIGNAL(loadStarted()), this, SLOT(newPageLoading()));
+    connect(this, SIGNAL(loadFinished(bool)), this, SLOT(pageLoaded(bool)));
+}
+
+void WebView::paintEvent(QPaintEvent *event)
+{
+    if (inLoading && loadingTime.elapsed() < 750) {
+        QPainter painter(this);
+        painter.setBrush(Qt::white);
+        painter.setPen(Qt::NoPen);
+        foreach (const QRect &rect, event->region().rects()) {
+            painter.drawRect(rect);
+        }
+    } else {
+        QWebView::paintEvent(event);
+    }
+}
+
+void WebView::newPageLoading()
+{
+    inLoading = true;
+    loadingTime.start();
+}
+
+void WebView::pageLoaded(bool)
+{
+    inLoading = false;
+    update();
+}
diff --git a/demos/embedded/anomaly/src/webview.h b/demos/embedded/anomaly/src/webview.h
new file mode 100644
index 0000000000..a7426c6ad7
--- /dev/null
+++ b/demos/embedded/anomaly/src/webview.h
@@ -0,0 +1,25 @@
+#ifndef WEBVIEW_H
+#define WEBVIEW_H
+
+#include <QWebView>
+#include <QTime>
+
+class WebView : public QWebView
+{
+    Q_OBJECT
+public:
+    WebView(QWidget *parent = 0);
+
+protected:
+    void paintEvent(QPaintEvent *event);
+
+private slots:
+    void newPageLoading();
+    void pageLoaded(bool ok);
+
+private:
+    QTime loadingTime;
+    bool inLoading;
+};
+
+#endif // WEBVIEW_H