Added the QtWebKit bridge Image Analyzer example.

Originally written by Jervey Kong.

Task-number: QTBUG-14154
Reviewed-by: David Boddie

5 files changed, 160 insertions, 2 deletions

diff --git a/doc/src/examples/webkit-bridge-imageanalyzer.qdoc b/doc/src/examples/webkit-bridge-imageanalyzer.qdoc
new file mode 100644
index 0000000..efc5623
--- /dev/null
+++ b/doc/src/examples/webkit-bridge-imageanalyzer.qdoc
@@ -0,0 +1,155 @@
+/****************************************************************************
+**
+** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:FDL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Free Documentation License
+** Alternatively, this file may be used under the terms of the GNU Free
+** Documentation License version 1.3 as published by the Free Software
+** Foundation and appearing in the file included in the packaging of this
+** file.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+/*!
+    \example webkit/imageanalyzer
+    \startpage {index.html} {Qt Reference Documentation}
+    \title The Webkit Bridge Tutorial - Hybrid Client Application
+
+    In this example, we will show how to write a hybrid application using
+\l{The QtWebKit Bridge}{QtWebKit Bridge}, which distinguishes itself from a
+thin client in that it performs heavy calculations on the client side in C++,
+like a native application, but presents nothing more than a \c QWebView for its
+user interface, displaying web content written in HTML/JavaScript. The
+application uses QtConcurrent to distribute its work across as many CPU cores as
+are available from the system, so it can process each image in parallel.
+
+Initially, you will see a user interface with an empty list of images. Clicking
+on some of the images in the lower pane below adds them to the list view above,
+as shown in the screenshot below.
+
+    \image webkit-imageanalyzer-screenshot.png
+
+Now, we can click on \bold Analyze, and each image is analyzed using some
+computationally intensive C++ function, in parallel and on different cores.
+Progress is shown while the analysis is proceeding.
+
+    \image webkit-imageanalyzer-progress.png
+
+and in the end, we will see something like this, where the average RGB values of
+each image are shown.
+
+    \image webkit-imageanalyzer-complete.png
+
+The MainWindow is defined in C++, and creates a \c QNetworkCache and a
+\c QWebView, and tells the \c QWebView to load the starting page, providing us
+with a user interface for the client.
+
+  \snippet examples/webkit/imageanalyzer/mainwindow.cpp MainWindow - constructor
+
+In this example, the sample content is addressed with the \tt qrc:/index.html
+URL. \tt qrc:/ indicates that the file is stored as a Qt resource (attached to
+the executable). In a real-world application, the content and images would
+likely be retrieved from the network rather than from resources.
+
+We wish to initialize an object reference in the JavaScript web page to point
+to our \tt ImageAnalyzer before any other scripts are run. To do this, we
+connect the \c javaScriptWindowObjectCleared() signal to a slot which does the
+object creation and handoff to JavaScript.
+
+  \snippet examples/webkit/imageanalyzer/mainwindow.cpp MainWindow - addJSObject
+
+The ImageAnalyzer object is created and added to a JavaScript object on the web
+page's mainFrame with \c addToJavaScriptWindowObject().
+
+    The start page is resources/index.html.
+    In one of its <div> regions, we have images, each
+    with an \c onClick() handler that calls \c addImage().
+
+    \snippet examples/webkit/imageanalyzer/resources/index.html sample images
+
+    Clicking an image adds it to an images list.
+
+    \snippet examples/webkit/imageanalyzer/resources/index.html addImage
+
+The \bold {Analyze} button at the bottom of the image list is clicked when we
+want to start the analysis:
+
+    \snippet examples/webkit/imageanalyzer/resources/index.html images list
+
+When the user clicks the \bold {Analyze} button, \c analyzeImages() is called,
+another regular JavaScript method, shown below.
+Notice it assumes the \c imageAnalyzer object is already defined and initialized
+in JavaScript space, but we guaranteed that by connecting our setup slot to the
+appropriate signal, \c javaScriptWindowObjectCleared().
+
+    \snippet examples/webkit/imageanalyzer/resources/index.html analyzeImages
+
+The only methods on \c ImageAnalyzer that we can or do call from JavaScript are
+those which are exposed through Qt's MetaObject system: property getter/setter
+methods,
+\c public \c slots, \c signals, and other \c Q_INVOKABLE functions.
+
+\snippet examples/webkit/imageanalyzer/imageanalyzer.h ImageAnalyzer - public interface
+\dots
+\snippet examples/webkit/imageanalyzer/imageanalyzer.h ImageAnalyzer - private members
+
+Most of the members are set up in the constructor:
+
+\snippet examples/webkit/imageanalyzer/imageanalyzer.cpp ImageAnalyzer - Constructor
+
+Back on the JavaScript side, we want to connect signals from this object to
+JavaScript functions on our web page, after the web page is loaded, but before
+the images are analyzed.
+
+From \c connectSlots(), we can see how to connect signals from the imageAnalyzer
+object to regular JavaScript functions, which can also behave like slots. We use
+this to monitor and display progress from the C++ side.
+
+    \snippet examples/webkit/imageanalyzer/resources/index.html connect slots
+
+The only public slot is \c startAnalysis(), called to place
+a list of URLs into the image analyzer's QtConcurrent processing queue
+from JavaScript space.
+
+\snippet examples/webkit/imageanalyzer/imageanalyzer.cpp ImageAnalyzer - startAnalysis
+
+The images need to be loaded again now, which is why fetchURLs first checks the
+cache to see if we can save an extra network get.
+
+\snippet examples/webkit/imageanalyzer/imageanalyzer.cpp ImageAnalyzer - fetchURLs
+
+For the images that were not in the cache, \c handleReply()
+will load them into a QImage when the data is ready.
+
+\snippet examples/webkit/imageanalyzer/imageanalyzer.cpp ImageAnalyzer - handleReply
+
+After the images are loaded, they are queued up in preparation to be
+sent in a batch for analysis to a \c QFutureWatcher, which will distribute the
+processing across multiple threads and cores, depending on how many are available.
+
+\snippet examples/webkit/imageanalyzer/imageanalyzer.cpp ImageAnalyzer - queueImage
+
+The function that gets performed on each image is \c averageRGB(),
+as specified in argument 2 to the \c QtConcurrent::mapped() function.
+Notice it repeats the same calculations 100 times on each pixel to keep the CPU
+very busy. This is done only for the purposes of the demo so that the analysis
+takes a noticeable time to complete.
+
+\snippet examples/webkit/imageanalyzer/imageanalyzer.cpp ImageAnalyzer - averageRGB
+
+*/
+
diff --git a/doc/src/getting-started/examples.qdoc b/doc/src/getting-started/examples.qdoc
index bfe7be9..398eee8 100644
--- a/doc/src/getting-started/examples.qdoc
+++ b/doc/src/getting-started/examples.qdoc
@@ -32,7 +32,7 @@
    Qt includes a set of examples that cover nearly every aspect of Qt
    development. They aren't meant to be impressive when you run them,
    but in each case the source code has been carefully written to
-   illustrate one or more best Qt programming practices. 
+   illustrate one or more best Qt programming practices.
 
    You can run the examples from the \l{Examples and Demos Launcher}
    application (except see \l{QML Examples and Demos} {QML Examples}
@@ -764,6 +764,9 @@
     \row \o \l{webkit/googlechat}{Google Chat}
     \o A real-world example that shows how an existing Web-based service can be accessed
     using QtWebKit.
+    \row \o \l{webkit/imageanalyzer}{Image Analyzer}\raisedaster
+    \o A \l{The QtWebKit Bridge}{QtWebKit bridge} application which contains a
+    web interface and client-side processing.
     \row \o \l{webkit/previewer}{Previewer}\raisedaster
     \o Shows how to make a simple Web page previewer by using Qt's text input widgets
     together with a QWebView widget.
@@ -776,7 +779,7 @@
 */
 
 /*!
-    \page examples-helpsystem.html 
+    \page examples-helpsystem.html
     \ingroup all-examples
     \title Help System Examples
     \brief Adding interactive help to your Qt application.
diff --git a/doc/src/images/webkit-imageanalyzer-complete.png b/doc/src/images/webkit-imageanalyzer-complete.png
new file mode 100644
index 0000000..47c0ee1
--- /dev/null
+++ b/doc/src/images/webkit-imageanalyzer-complete.png
diff --git a/doc/src/images/webkit-imageanalyzer-progress.png b/doc/src/images/webkit-imageanalyzer-progress.png
new file mode 100644
index 0000000..5bab890
--- /dev/null
+++ b/doc/src/images/webkit-imageanalyzer-progress.png
diff --git a/doc/src/images/webkit-imageanalyzer-screenshot.png b/doc/src/images/webkit-imageanalyzer-screenshot.png
new file mode 100644
index 0000000..987f8a2
--- /dev/null
+++ b/doc/src/images/webkit-imageanalyzer-screenshot.png