Merge branch '4.7' of scm.dev.nokia.troll.no:qt/qt-qml into 4.7-integration

* '4.7' of scm.dev.nokia.troll.no:qt/qt-qml: (32 commits)
  Correctly support translation in QDeclarativePixmapCache
  Improve warning for non-Item delegates.
  Correctly support translation in QDeclarativeCompiler
  Small calculator fix.
  Improve declarative calculator example.
  Update examples autotest to use the runtime directly
  Support valuetypes as method return values
  Compile without Qt3 support.
  Doc
  Simplify dynamic resource loading to avoid cluttering Text API.
  Add Component.onDestruction attached property
  Use qmlInfo for image loading errors, not qWarning().
  Visual test updates.
  Rename section so that it's not linked to by references to "JavaScript"
  Doc improvements
  Comments
  Remove unused parameter
  Correctly resolve, and load, IMG tags in Text element.
  Rename "sql" test so autotester doesn't get confused.
  Should work now, don't skip.
  ...

1 files changed, 97 insertions, 51 deletions

diff --git a/doc/src/declarative/integrating.qdoc b/doc/src/declarative/integrating.qdoc
index 165a735..d4034fa 100644
--- a/doc/src/declarative/integrating.qdoc
+++ b/doc/src/declarative/integrating.qdoc
@@ -43,44 +43,56 @@
 \page qml-integration.html
 \title Integrating QML with existing Qt UI code
 
-If you have existing Qt UI code which does not use QML you can still
-add QML to your UI, without having to rewrite it.
-
-\section1 Adding QML to a \l{QWidget} based UI
-If you have an existing QWidget based UI you can simply write new custom
-widgets in QML. To integrate them into your application you can create a
-QDeclarativeView widget, and load the QML file into that. You'll then have a new widget
-containing your declarative UI, and you can interact with it through the
-QDeclarativeView interface. The one drawback of this approach is that QDeclarativeView is a lot
-heavier than a QWidget in terms of memory consumption and initialization speed,
-and so having large numbers of them may lead to performance degredation.
-
-For a smooth transition from a QWidget based UI to a QML based UI, simply
-rewrite your widgets in QML one at a time, using the above method. When
-all of your widgets are written in QML you can rewrite your main widget in
-QML, so as to load the other widgets in QML instead of using QDeclarativeViews. Then
-you just load the main QML file on startup.
-
-Keep in mind that QWidgets were designed for different sorts of UIs than QML
-was, and so it is not always a good idea to switch. QWidgets are a better
-choice if your UI is comprised of a small number of complex and static
-elements, and QML is a better choice if your UI is comprised of a large number
+There are a number of ways to integrate QML into QWidget-based UI applications,
+depending on the characteristics of your existing UI code.
+
+
+\section1 Integrating with a \l{QWidget}-based UI
+
+If you have an existing QWidget-based UI, QML widgets can be integrated into
+it using QDeclarativeView. QDeclarativeView is a subclass of QWidget so you
+can add it to your user interface like any other QWidget. Use 
+QDeclarativeView::setSource() to load a QML file into the view, then add the 
+view to your UI:
+
+\code
+QDeclarativeView *qmlView = new QDeclarativeView;
+qmlView->setSource(QUrl::fromLocalFile("myqml.qml"));
+
+QWidget *widget = myExistingWidget();
+QVBoxLayout *layout = new QVBoxLayout(widget);
+widget->addWidget(qmlView);
+\endcode
+
+The one drawback to this approach is that QDeclarativeView is slower to initialize
+and uses more memory than a QWidget, and creating large numbers of QDeclarativeView
+objects may lead to performance degradation. If this is the case, it may be 
+better to rewrite your widgets in QML, and load the widgets from a main QML widget
+instead of using QDeclarativeView.
+
+Keep in mind that QWidgets were designed for a different type of user interface
+than QML, so it is not always a good idea to port a QWidget-based application to
+QML. QWidgets are a better choice if your UI is comprised of a small number of
+complex and static elements, and QML is a better choice if your UI is comprised of a large number
 of simple and dynamic elements.
 
-\section1 Adding QML to a QGraphicsView based UI
 
-If you have an existing Graphics View based UI you can create new
-items in QML, and use \l{QDeclarativeComponent} to create \l{QGraphicsObject}s
-from the QML files. These \l{QGraphicsObject}s can then be placed into
-your \l{QGraphicsScene} using \l{QGraphicsScene::addItem()} or by
-reparenting them to an item already in the \l{QGraphicsScene}.
+\section1 Integrating with a QGraphicsView-based UI
+
+\section2 Adding QML widgets to a QGraphicsScene
 
-Example, for local QML files:
+If you have an existing UI based on the \l{The Graphics View Framework}{Graphics View Framework},
+you can integrate QML widgets directly into your QGraphicsScene. Use
+QDeclarativeComponent to create a QGraphicsObject from a QML file, and
+place the graphics object into your scene using \l{QGraphicsScene::addItem()}, or 
+reparent it to an item already in the \l{QGraphicsScene}.
+
+For example:
 
 \code
-QGraphicsScene* scene = new QGraphicsScene;
+QGraphicsScene* scene = myExistingGraphicsScene();
 QDeclarativeEngine *engine = new QDeclarativeEngine;
-QDeclarativeComponent component(engine, QUrl::fromLocalFile(filename));
+QDeclarativeComponent component(engine, QUrl::fromLocalFile("myqml.qml"));
 QGraphicsObject *object =
     qobject_cast<QGraphicsObject *>(component.create());
 scene->addItem(object);
@@ -90,26 +102,60 @@ The following QGraphicsView options are recommended for optimal performance
 of QML UIs:
 
 \list
-\o QGraphicsView::setOptimizationFlags(QGraphicsView::DontSavePainterState);
-\o QGraphicsView::setViewportUpdateMode(QGraphicsView::BoundingRectViewportUpdate);
-\o QGraphicsScene::setItemIndexMethod(QGraphicsScene::NoIndex);
+\o QGraphicsView::setOptimizationFlags(QGraphicsView::DontSavePainterState)
+\o QGraphicsView::setViewportUpdateMode(QGraphicsView::BoundingRectViewportUpdate)
+\o QGraphicsScene::setItemIndexMethod(QGraphicsScene::NoIndex)
 \endlist
 
-\section1 Using existing QGraphicsWidgets in QML
-Another way of integrating with a QGraphicsView based UI is to expose your
-existing QGraphicsWidgets to QML, and constructing your scene in QML. Note that
-this approach will not work with QGraphicsItems which are not QGraphicsWidgets,
-and that this approach allows you to integrate new items written in QML
-without using the above method.
-
-You can make custom C++ types 
-available in QML using the pair of macros listed in \l{Extending QML in C++}.
-While this is normally only useful for
-types that were designed for QML use, in conjunction with the
-\l{GraphicsObjectContainer} element QGraphicsWidget subclasses can also be
-used effectively (if they were designed, like QGraphicsWidget, to be controllable through Qt's property system).
-This way you can write your UI using QML, without having to rewrite your existing items.
-
-For details on implementing this approach see \l{Extending QML in C++} page for details on exposing your C++ types,
-and the \l{GraphicsObjectContainer} documentation for details about using it to wrap QGraphicsWidgets. 
+\section2 Loading QGraphicsWidget objects in QML
+
+An alternative approach is to expose your existing QGraphicsWidget objects to 
+QML and construct your scene in QML instead. To do this, you need to register
+any custom C++ types and create a plugin that registers the custom types
+so that they can be used from your QML file.
+
+Here is an example. Suppose you have two classes, \c RedSquare and \c BlueCircle,
+that both inherit from QGraphicsWidget. First, you need to register these two types
+using the \c QML_DECLARE_TYPE macro from \c <QtDeclarative/qdeclarative.h>, like this:
+
+\c [graphicswidgets/redsquare.h]
+\snippet doc/src/declarative/snippets/integrating/graphicswidgets/redsquare.h 0
+
+\c [graphicswidgets/bluecircle.h]
+\snippet doc/src/declarative/snippets/integrating/graphicswidgets/bluecircle.h 0
+
+Then, create a plugin by subclassing QDeclarativeExtensionPlugin, and register the
+types by calling qmlRegisterType(). Also export the plugin with Q_EXPORT_PLUGIN2.
+
+\c [graphicswidgets/shapesplugin.cpp]
+\snippet doc/src/declarative/snippets/integrating/graphicswidgets/shapesplugin.cpp 0
+
+Now write a project file that creates the plugin:
+
+\c [graphicswidgets/graphicswidgets.pro]
+\quotefile doc/src/declarative/snippets/integrating/graphicswidgets/graphicswidgets.pro
+
+And add a \c qmldir file that includes the \c graphicswidgets plugin from the \c lib
+subdirectory (as defined in the project file):
+
+\c [graphicswidgets/qmldir]
+\quotefile doc/src/declarative/snippets/integrating/graphicswidgets/qmldir
+
+Now, we can write a QML file that uses the \c RedSquare and \c BlueCircle widgets.
+(As an example, we can also create \c QGraphicsWidget items if we import the \c Qt.widgets
+module.)
+
+\c [main.qml]
+\quotefile doc/src/declarative/snippets/integrating/graphicswidgets/main.qml
+
+Here is a screenshot of the result:
+
+\image declarative-integrating-graphicswidgets.png 
+
+
+Note this approach of creating your graphics widgets from QML does not work 
+with QGraphicsItem objects that are not QGraphicsWidget-based, since they are not QObjects.
+
+See \l{Extending QML in C++} for further information on using C++ types.
+
 */