Documentation for the Pad Navigator Example.

This also does a few touch-ups on the source code.

11 files changed, 736 insertions, 111 deletions

diff --git a/doc/src/examples/padnavigator.qdoc b/doc/src/examples/padnavigator.qdoc
index 70e131e..e29a3b2 100644
--- a/doc/src/examples/padnavigator.qdoc
+++ b/doc/src/examples/padnavigator.qdoc
@@ -43,9 +43,555 @@
     \example graphicsview/padnavigator
     \title Pad Navigator Example
 
-    The Pad Navigator Example shows how you can use Graphics View
-    together with embedded widgets to create a simple but useful
-    dynamic user interface for embedded devices.
+    The Pad Navigator Example shows how you can use Graphics View together with
+    embedded widgets and Qt's \l{State Machine Framework} to create a simple
+    but useful, dynamic, animated user interface.
 
     \image padnavigator-example.png
+
+    The interface consists of a flippable, rotating pad with icons that can be
+    selected using the arrow keys on your keyboard or keypad. Pressing enter
+    will flip the pad around and reveal its back side, which has a form
+    embedded into a QGraphicsProxyWidget. You can interact with the form, and
+    press the enter key to flip back to the front side of the pad at any time.
+
+    Graphics View provides the QGraphicsScene class for managing and
+    interacting with a large number of custom-made 2D graphical items derived
+    from the QGraphicsItem class, and a QGraphicsView widget for visualizing
+    the items, with support for zooming and rotation.
+
+    This example consists of a \c RoundRectItem class, a \c FlippablePad class,
+    a \c PadNavigator class, a \c SplashItem class, and a \c main() function.
+
+    \section1 RoundRectItem Class Definition
+
+    The \c RoundRectItem class is used by itself to diplay the icons on the
+    pad, and as a base class for \c FlippablePad, the class for the pad itself.
+    The role of the class is to paint a round rectangle of a specified size and
+    gradient color, and optionally to paint a pixmap icon on top. To support \c
+    FlippablePad it also allows filling its contents with a plain window
+    background color.
+
+    Let's start by reviewing the \c RoundRectItem class declaration.
+
+    \snippet examples/graphicsview/padnavigator/roundrectitem.h 0
+
+    \c RoundRectItem inherits QGraphicsObject, which makes it easy to control
+    its properties using QPropertyAnimation. Its constructor takes a rectangle
+    to determine its bounds, and a color.
+
+    Besides implementing the mandatory \l{QGraphicsItem::paint()}{paint()} and
+    \l{QGraphicsItem::boundingRect()}{boundingRect()} pure virtual functions,
+    it also provides the \c pixmap and \c fill properties.
+
+    The \c pixmap property sets an optional pixmap that is drawn on top of the
+    round rectangle. The \c fill property will, when true, fill the round
+    rectangle contents with a fixed QPalette::Window background color.
+    Otherwise the contents are filled using a gradient based on the color
+    passed to \c RoundRectItem's constructor.
+
+    \snippet examples/graphicsview/padnavigator/roundrectitem.h 1
+
+    The private data members are:
+
+    \list
+    \o \c pix: The optional pixmap that is drawn on top of the rectangle.
+    \o \c fillRect: Corresponds to the \c fill property.
+    \o \c color: The configurable gradient color fill of the rectangle.
+    \o \c bounds: The bounds of the rectangle.
+    \o \c gradient: A precalculated gradient used to fill the rectangle.
+    \endlist
+
+    We will now review the \c RoundRectItem implementation. Let's start by
+    looking at its constructor:
+
+    \snippet examples/graphicsview/padnavigator/roundrectitem.cpp 0
+
+    The constructor initializes its member variables and forwards the \c parent
+    argument to QGraphicsObject's constructor. It then constructs the linear
+    gradient that is used in \l{QGraphicsItem::paint()}{paint()} to draw the
+    round rectangle's gradient background. The linear gradient's starting point
+    is at the top-left corner of the bounds, and the end is at the bottom-left
+    corner. The start color is identical to the color passed as an argument,
+    and a slightly darker color is chosen for the final stop.
+
+    We store this gradient as a member variable to avoid having to recreate the
+    gradient every time the item is repainted.
+
+    Finally we set the cache mode
+    \l{QGraphicsItem::ItemCoordinateCache}{ItemCoordinateCache}. This mode
+    causes the item's rendering to be cached into an off-screen pixmap that
+    remains persistent as we move and transform the item. This mode is ideal
+    for this example, and works particularily well with OpenGL and OpenGL ES.
+
+    \snippet examples/graphicsview/padnavigator/roundrectitem.cpp 1
+
+    The \c pixmap property implementation simple returns the member pixmap, or
+    sets it and then calls \l{QGraphicsItem::update()}{update()}.
+
+    \snippet examples/graphicsview/padnavigator/roundrectitem.cpp 2
+
+    As the \l{QGraphicsItem::paint()}{paint()} implementation below draws a
+    simple drop shadow down and to the right of the item, we return a slightly
+    adjusted rectangle from \l{QGraphicsItem::boundingRect()}{boundingRect()}.
+
+    \snippet examples/graphicsview/padnavigator/roundrectitem.cpp 3
+
+    The \l{QGraphicsItem::paint()}{paint()} implementation starts by rendering
+    a semi transparent black round rectangle drop shadow, two units down and to
+    the right of the main item.
+
+    \snippet examples/graphicsview/padnavigator/roundrectitem.cpp 4
+
+    We then draw the "foreground" round rectangle itself. The fill depends on
+    the \c fill property; if true, we will with a plain QPalette::Window color.
+    We get the corrent brush from QApplication::palette(). We assign a single
+    unit wide pen for the stroke, assign the brush, and then draw the
+    rectangle.
+
+    \snippet examples/graphicsview/padnavigator/roundrectitem.cpp 5
+
+    If a pixmap has been assigned to the \e pixmap property, we draw this
+    pixmap in the center of the rectangle item. The pixmaps are scaled to match
+    the size of the icons; in arguably a better approach would have been to
+    store the icons with the right size in the first places.
+
+    \snippet examples/graphicsview/padnavigator/roundrectitem.cpp 6
+
+    Finally, for completeness we include the \c fill property implementation.
+    It returns the \c fill member variable's value, and when assigned to, it
+    calls \l{QGraphicsItem::update()}{update()}.
+
+    As mentioned already, \c RoundRectItem is the base class for \c
+    FlippablePad, which is the class representing the tilting pad itself. We
+    will proceed to reviewing \c FlippablePad.
+
+    \section1 FlippablePad Class Definition
+
+    \c FlippablePad is, in addition to its inherited \c RoundRectItem
+    responsibilities, responsible for creating and managing a grid of icons.
+
+    \snippet examples/graphicsview/padnavigator/flippablepad.h 0
+
+    Its declaration is very simple: It inherits \c RoundRectItem and does not
+    need any special polymorphic behavior. It's suitable to declare its own
+    constructor, and a getter-function that allows \c PadNavigator to access
+    the icons in the grid by (row, column).
+
+    The example has no "real" behavior or logic of any kind, and because of
+    that, the icons do not need to provide any \e behavior or special
+    interactions management. In a real application, however, it would be
+    natural for the \c FlippablePad and its icons to handle more of the
+    navigation logic. In this example, we have chosen to leave this to
+    the \c PadNavigator class, which we will get back to below.
+
+    We will now review the \c FlippablePad implementation. This implementation
+    starts with two helper functions: \c boundsFromSize() and \c
+    posForLocation():
+
+    \snippet examples/graphicsview/padnavigator/flippablepad.cpp 0
+
+    \c boundsForSize() takes a QSize argument, and returns the bounding
+    rectangle of the flippable pad item. The QSize determines how many rows and
+    columns the icon grid should have. Each icon is given 150x150 units of
+    space, and this determines the bounds.
+
+    \snippet examples/graphicsview/padnavigator/flippablepad.cpp 1
+
+    \c posForLocation() returns the position of an icon given its row and
+    column position. Like \c boundsForSize(), the function assumes each icon is
+    given 150x150 units of space, and that all icons are centered around the
+    flippable pad item's origin (0, 0).
+
+    \snippet examples/graphicsview/padnavigator/flippablepad.cpp 2
+
+    The \c FlippablePad constructor passes suitable bounds (using \c
+    boundsForSize()) and specific color to \c RoundRectItem's constructor.
+
+    \snippet examples/graphicsview/padnavigator/flippablepad.cpp 3
+
+    It then loads pixmaps from compiled-in resources to use for its icons.
+    QDirIterator is very useful in this context, as it allows us to fetch all
+    resource "*.png" files inside the \c :/images directory without explicitly
+    naming the files.
+
+    We also make sure not to load more pixmaps than we need.
+
+    \snippet examples/graphicsview/padnavigator/flippablepad.cpp 4
+
+    Now that we have the pixmaps, we can create icons, position then and assign
+    pixmaps. We start by finding a suitable size and color for the icons, and
+    initializing a convenient grid structure for storing the icons. This \c
+    iconGrid is also used later to find the icon for a specific (column, row)
+    location.
+
+    For each row and column in our grid, we proceed to constructing each icon
+    as an instance of \c RoundRectItem. The item is placed by using the \c
+    posForLocation() helper function. To make room for the slip-behind
+    selection item, we give each icon a \l{QGraphicsItem::zValue()}{Z-value} of
+    1. The pixmaps are distributed to the icons in round-robin fasion.
+
+    Again, this approach is only suitable for example purposes. In a real-life
+    application where each icon represents a specific action, it would be more
+    natural to assign the pixmaps directly, or that the icons themselves
+    provide suitable pixmaps.
+
+    \snippet examples/graphicsview/padnavigator/flippablepad.cpp 5
+
+    Finally, the \c iconAt() function returns a pointer to the icon at a
+    specific row and column. It makes a somewhat bold assumption that the input
+    is valid, which is fair because the \c PadNavigator class only calls this
+    function with correct input.
+
+    We will now review the \c SplashItem class.
+
+    \section1 SplashItem Class Definition
+
+    The \c SplashItem class represents the "splash window", a semitransparent
+    white overlay with text that appears immediately after the application has
+    started, and disappears after pressing any key. The animation is controlled
+    by \c PadNavigator; this class is very simple by itself.
+
+    \snippet examples/graphicsview/padnavigator/splashitem.h 0
+
+    The class declaration shows that \c SplashItem inherits QGraphicsObject to
+    allow it to be controlled by QPropertyAnimation. It reimplements the
+    mandatory \l{QGraphicsItem::paint()}{paint()} and
+    \l{QGraphicsItem::boundingRect()}{boundingRect()} pure virtual functions,
+    and keeps a \c text member variable which will contain the information text
+    displayed on this splash item.
+
+    Let's look at its implementation.
+
+    \snippet examples/graphicsview/padnavigator/splashitem.cpp 0
+
+    The constructor forwards to QGraphicsObject as expected, assigns a text
+    message to the \c text member variable, and enables
+    \l{QGraphicsItem::DeviceCoordinateCache}{DeviceCoordinateCache}. This cache
+    mode is suitable because the splash item only moves and is never
+    transformed, and because it contains text, it's important that it has a
+    pixel perfect visual appearance (in constrast to
+    \l{QGraphicsItem::ItemCoordinateCache}{ItemCoordinateCache}, where the
+    visual appearance is not as good).
+
+    We use caching to avoid having to relayout and rerender the text for each
+    frame. An alterative approach would be to use the new QStaticText class.
+
+    \snippet examples/graphicsview/padnavigator/splashitem.cpp 1
+
+    \c SplashItem's bounding rectangle is fixed at (400x175).
+
+    \snippet examples/graphicsview/padnavigator/splashitem.cpp 2
+
+    The \l{QGraphicsItem::paint()}{paint()} implementation draws a clipped
+    round rectangle with a thick 2-unit border and a semi-transparent white
+    background. It proceeds to finding a suitable text area by adjusting the
+    splash item's bounding rectangle with 10 units in each side. The text is
+    rendered inside this rectangle, with top-left alignment, and with word
+    wrapping enabled.
+
+    The main class now remains. We will proceed to reviewing \c PadNavigator.
+
+    \section1 PadNavigator Class Definition
+
+    \c PadNavigator represents the main window of our Pad Navigator Example
+    application. It creates and controls a somewhat complex state machine, and
+    several animations. Its class declaration is very simple:
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.h 0
+
+    It inherits QGraphicsView and reimplements only one function:
+    \l{QGraphicsView::resizeEvent()}{resizeEvent()}, to ensure the scene is
+    scaled to fit inside the view when resizing the main window.
+
+    The \c PadNavigator constructor takes a QSize argument that determines the
+    number or rows and columns in the grid.
+
+    It also keeps a private member instance, \c form, which is the generated
+    code for the pad's back side item's QGraphicsProxyWidget-embedded form.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 0
+
+    \c PadNavigator's constructor is a bit long. In short, its job is to create
+    all items, including the \c FlippablePad, the \c SplashItem and the
+    QGraphicsProxyWidget \c backItem, and then to set up all animations, states
+    and transitions that control the behavior of the application.
+
+    It starts out simple, by forwarding to QGraphicsView's constructor.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 1
+
+    The first item to be created is \c SplashItem. This is going to be a top-level
+    item in the scene, next to \c FlippablePad, and stacked on top of it, so we
+    assign it a \l{QGraphicsItem::zValue()}{Z-value} of 1.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 2
+
+    Now we construct the \c FlippablePad item, passing its column-row count to
+    its constructor.
+
+    The pad is constrolled by three transformations, and we create one
+    QGraphicsRotation object for each of these.
+
+    \list
+    \o \c flipRotation: Rotates the grid around its Qt::YAxis. This rotation is
+    animated from 0 to 180, and eventually back, when enter is pressed on the
+    keyboard, flipping the pad around.
+    \o \c xRotation: Rotates the grid around its Qt::XAxis. This is used to
+    tilt the pad vertically corresponding to which item is currently selected.
+    This way, the selected item is always kept in front.
+    \o \c yRotation: Rotates the grid around its Qt::YAxis. This is used to
+    tilt the pad horizontally corresponding to which item is selected. This
+    way, the selected item is always kept in front.
+    \endlist
+
+    The combination of all three rotations is assigned via
+    QGraphicsItem::setTransformations().
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 3
+
+    Now we construct the QGraphicsProxyWidget-embedded \c backItem. The proxy
+    widget is created as a child of the pad. We create a new QWidget and
+    populate it with the \c form member. To ensure the \c hostName line edit is
+    the first to receive input focus when this item is shown, we call
+    \l{QWidget::setFocus()}{setFocus()} immediately. This will not give the
+    widget focus right away; it will only prepare the item to automatically
+    receive focus once it is shown.
+
+    The QWidget based form is embedded into the proxy widget. The proxy is
+    hidden initially; we only want to show it when the pad is rotated at least
+    90 degrees, and we also rotate the proxy itself by 180 degrees. This way we
+    give the impression that the proxy widget is "behind" the flipped pad, when
+    in fact, it's actually \e{on top of it}.
+
+    We enable \l{QGraphicsItem::ItemCoordinateCache}{ItemCoordinateCache} to
+    ensure the flip animation can run smoothly.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 4
+
+    We now create the selection item. This is simply another instance of \c
+    RoundRectItem that is slightly larger than the icons on the pad. We create
+    it as an immediate child of the \c FlippablePad, so the selection item is a
+    sibling to all the icons. By giving it a
+    \l{QGraphicsItem::zValue()}{Z-value} of 0.5 we ensure it will slide beteen
+    the pad and its icons.
+
+    What follows now is a series of animation initializations.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 5
+
+    We begin with the animations that apply to the splash item. The first
+    animation, \c smoothSplashMove, ensures that the "y" property of \c splash
+    will be animated with a 250-millisecond duration
+    \l{QEasingCurve::InQuad}{InQuad} easing function. \c smoothSplashOpacity
+    ensures the opacity of \c splash eases in and out in 250 milliseconds.
+
+    The values are assigned by \c PadNavigator's state machine, which is
+    created later.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 6
+
+    These are the animations that control the selection item's movement and the
+    \c xRotation and \c yRotation QGraphicsRotation objects that tilt the pad.
+    All animations have a duration of 125 milliseconds, and they all use the
+    \l{QEasingCurve::InOutQuad}{InOutQuad} easing function.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 7
+
+    We now create the animations that control the flip-effect when you press
+    the enter key. The main goal is to rotate the pad by 180 degrees or back,
+    but we also need to make sure the selection item's tilt rotations are reset
+    back to 0 when the pad is flipped, and restored back to their original
+    values when flipped back:
+
+    \list
+    \o \c smoothFlipRotation: Animates the main 180 degree rotation of the pad.
+    \o \c smoothFlipScale: Scales the pad out and then in again while the pad is rotating.
+    \o \c smoothFlipXRotation: Animates the selection item's X-tilt to 0 and back.
+    \o \c smoothFlipYRotation: Animates the selection item's Y-tilt to 0 and back.
+    \o \c flipAnimation: A parallel animation group that ensures all the above animations are run in parallel.
+    \endlist
+
+    All animations are given a 500 millisecond duration and an
+    \l{QEasingCurve::InOutQuad}{InOutQuad} easing function.
+
+    It's worth taking a close look at \c smoothFlipScale. This animation's
+    start and end values are both 1.0, but at animation step 0.5 the
+    animation's value is 0.7. This means that after 50% of the animation's
+    duration, or 250 milliseconds, the pad will be scaled down to 0.7x of its
+    original size, which gives a great visual effect while flipping.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 8
+
+    This section uses a trick to ensure that certain properties are assigned
+    precisely when the flip animation passes 50%, or 90 degrees, rotation. In
+    short, the pad's icons and selection item are all hidden, the pad's \c fill
+    property is enabled, and \c backItem is shown when flipping over. When
+    flipping back, the reverse properties are applied.
+
+    The way this is achieved is by running a sequential animation in parallel
+    to the other animations. This sequence, dubbed \c setVariablesSequence,
+    starts with a 250 millisecond pause, and then executes several animations
+    with a duration of 0. Each animation will ensure that properties are set
+    immediate at this point.
+
+    This approach can also be used to call functions or set any other
+    properties at a specific time while an animation is running.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 9
+
+    We will now create the state machine. The whole \c PadNavigator state
+    machinery is controlled by one single state machine that has a
+    straight-forward state structure. The state engine itself is created
+    as a child of the \c PadNavigator itself. We then create three top level
+    states:
+
+    \list
+    \o \c splashState: The initial state where the splash item is visible.
+    \o \c frontState: The base state where the splash is gone and we can see
+    the front side of the pad, and navigate the selection item.
+    \o \c backState: The flipped state where the \c backItem is visible, and we
+    can interact with the QGraphicsProxyWidget-embedded form.
+    \endlist
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 10
+
+    Each state assigns specific properties to objects on entry. Most
+    interesting perhaps is the assignment of the value 0.0 to the pad's \c
+    flipRotation angle property when in \c frontState, and 180.0 when in \c
+    backState. At the end of this section we register default animations with
+    the state engine; these animations will apply to their respective objects
+    and properties for any state transition. Otherwise it's common to assign
+    animations to specific transitions.
+
+    The \c splashState state is set as the initial state. This is required
+    before we start the state engine. We proceed with creating some
+    transitions.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 11
+
+    QEventTransition defines a very flexible transition type. You can use this
+    class to trigger a transition based on an object receiving an event of a
+    specific type. In this case, we would like to transition from \c
+    splashState into \c frontState if \c PadNavigator receives any key press
+    event (QEvent::KeyPress).
+
+    We register the \c splashItem's animations to this transition to ensure they
+    are used to animate the item's movement and opacity.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 12
+
+    We use QKeyEventTransition to capture specific key events. In this case, we
+    detect that the user presses Qt::Key_Return or Qt::Key_Enter, and use this
+    to trigger transitions between \c frontState and backState. We register \c
+    flipAnimation, our complex parallel animation group, with these
+    transitions.
+
+    We continue by defining the states for each of the icons in the grid.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 13
+
+    We will use state groups to control transitions between icons. Each icon
+    represents a \e substate of \c frontState. We will then define transitions
+    between the states by detecting key presses, using QKeyEventTransition.
+
+    We start by creating all the substates, and at the same time we create a
+    temporary grid structure for the states to make it easier to find which
+    states represents icons that are up, down, left and to the right each
+    other.
+
+    Once the first substate is known, we set this up as the initial substate of
+    \c frontState. We will use the (0, 0), or top-left, icon for the initial
+    substate. We initialze the selection item's position to be exactly where
+    the top-left icon is.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 14
+
+    We can now create four transitions for each icon. Each transition ensures
+    that we move to the state corresponding to which arrow key has been
+    pressed. It's clear from this techinique that we could design any other
+    specific transitions to and from each of the sub states depending on these
+    and other keys.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 15
+
+    Also, for each of the icons, we assign suitable values to the \c xRotation
+    and \c yRotation objects' "angle"-properties. If you recall, these
+    properties "tilt" the pad corresponding to which item is currently
+    selected. We ensure each icon is invisible when the pad is flipped, and
+    visible when the pad is not flipped. To ensure the visible property is
+    assigned at the right time, we add property-controlling animations to the
+    \c setVariableSequence animation defined earlier.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 16
+
+    We are now finished with all states, transitions, and animations. We now
+    create the scene that will contain all our items. The scene gets a defined
+    background pixmap, and we disable item indexing (as most items in this
+    scene are animated). We add our \c pad item to the scene, and use its
+    bounding rectangle to fixate the scene rectangle. This rectangle is used by
+    the view to find a suitable size for the application window.
+
+    Then the scene is assigned to the view, or in our case, \c PadNavigator
+    itself.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 17
+
+    Now that the scene has received its final size, we can position the splash
+    item at the very top, find its fade-out position, and add it to the scene.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 18
+
+    The view toggles a few necessary properties:
+
+    \list
+    \o It disables its scroll bars - this application has no use for scroll bars.
+    \o It assigns a minimum size. This is necessary to avoid numerical errors
+    in our fit-in-view \c resizeEvent() implementation.
+    \o It sets \l{QGraphicsView::FullViewportUpdate}{FullViewportUpdate}, to
+    ensure QGraphicsView doesn't spend time figuring out precisely what needs
+    to be redrawn. This application is very simple - if anything changes,
+    everything is updated.
+    \o It enables background caching - this makes no performance difference
+    with OpenGL, but without OpenGL it avoids unnecessary re-scaling of the
+    background pixmap.
+    \o It sets render hints that increase rendering quality.
+    \o If OpenGL is supported, a QGLWidget viewport is assigned to the view.
+    \endlist
+
+    Finally, we start the state engine.
+
+    \snippet examples/graphicsview/padnavigator/padnavigator.cpp 19
+
+    The \l{QGraphicsView::resizeEvent()}{resizeEvent()} implementation calls
+    the base implementation, and then calls QGraphicsView::fitInView() to scale
+    the scene so that it fits perfectly inside the view.
+
+    By resizing the main application window, you can see this effect yourself.
+    The scene contents grow when you make the window larger, and shrink when
+    you make it smaller, while keeping the aspect ratio intact.
+
+    \section1 The main() Function
+
+    \snippet examples/graphicsview/padnavigator/main.cpp 0
+
+    The \c main function creates the QApplication instance, uses
+    Q_INIT_RESOURCE to ensure our compiled-in resources aren't removed by the
+    linker, and then creates a 3x3 \c PadNavigator instance and shows it.
+
+    Our flippable pad shows up with a suitable splash item once control returns
+    to the event loop.
+
+    \section1 Performance Notes
+
+    The example uses OpenGL if this is available, to achieve optimal
+    performance; otherwise perspective tranformations can be quite costly.
+
+    Although this example does use QGraphicsProxyWidget to demonstrate
+    integration of Qt widget components integrated into Graphics View, using
+    QGraphicsProxyWidget comes with a performance penalty, and is therefore not
+    recommended for embedded development.
+
+    This example uses extensive item caching to avoid rerendering of static
+    elements, at the expense of graphics memory.
 */
diff --git a/doc/src/getting-started/examples.qdoc b/doc/src/getting-started/examples.qdoc
index 542f672..f511cd6 100644
--- a/doc/src/getting-started/examples.qdoc
+++ b/doc/src/getting-started/examples.qdoc
@@ -651,6 +651,7 @@
     \o \l{graphicsview/diagramscene}{Diagram Scene}\raisedaster
     \o \l{graphicsview/dragdroprobot}{Drag and Drop Robot}\raisedaster
     \o \l{graphicsview/elasticnodes}{Elastic Nodes}\raisedaster
+    \o \l{graphicsview/padnavigator}{Pad Navigator}\raisedaster
     \o \l{graphicsview/portedasteroids}{Ported Asteroids}
     \o \l{graphicsview/portedcanvas}{Ported Canvas}
     \endlist
diff --git a/examples/graphicsview/padnavigator/flippablepad.cpp b/examples/graphicsview/padnavigator/flippablepad.cpp
index 61f421f..58aea00 100644
--- a/examples/graphicsview/padnavigator/flippablepad.cpp
+++ b/examples/graphicsview/padnavigator/flippablepad.cpp
@@ -43,37 +43,43 @@
 
 #include <QtGui/QtGui>
 
+//! [0]
 static QRectF boundsFromSize(const QSize &size)
 {
     return QRectF((-size.width() / 2.0) * 150, (-size.height() / 2.0) * 150,
                   size.width() * 150, size.height() * 150);
 }
+//! [0]
 
-static QPointF posForLocation(int x, int y, const QSize &size)
+//! [1]
+static QPointF posForLocation(int column, int row, const QSize &size)
 {
-    return QPointF(x * 150, y * 150)
+    return QPointF(column * 150, row * 150)
         - QPointF((size.width() - 1) * 75, (size.height() - 1) * 75);
 }
+//! [1]
 
+//! [2]
 FlippablePad::FlippablePad(const QSize &size, QGraphicsItem *parent)
     : RoundRectItem(boundsFromSize(size), QColor(226, 255, 92, 64), parent)
 {
-    columns = size.width();
-
+//! [2]
+//! [3]
     int numIcons = size.width() * size.height();
     QList<QPixmap> pixmaps;
     QDirIterator it(":/images", QStringList() << "*.png");
     while (it.hasNext() && pixmaps.size() < numIcons)
         pixmaps << it.next();
+//! [3]
 
+//! [4]
     const QRectF iconRect(-54, -54, 108, 108);
     const QColor iconColor(214, 240, 110, 128);
-
     iconGrid.resize(size.height());
-
     int n = 0;
+
     for (int y = 0; y < size.height(); ++y) {
-        iconGrid[y].resize(columns);
+        iconGrid[y].resize(size.width());
         for (int x = 0; x < size.width(); ++x) {
             RoundRectItem *rect = new RoundRectItem(iconRect, iconColor, this);
             rect->setZValue(1);
@@ -83,8 +89,11 @@ FlippablePad::FlippablePad(const QSize &size, QGraphicsItem *parent)
         }
     }
 }
+//! [4]
 
-RoundRectItem *FlippablePad::iconAt(int x, int y) const
+//! [5]
+RoundRectItem *FlippablePad::iconAt(int column, int row) const
 {
-    return iconGrid[y][x];
+    return iconGrid[row][column];
 }
+//! [5]
diff --git a/examples/graphicsview/padnavigator/flippablepad.h b/examples/graphicsview/padnavigator/flippablepad.h
index 9adb18b..7d99536 100644
--- a/examples/graphicsview/padnavigator/flippablepad.h
+++ b/examples/graphicsview/padnavigator/flippablepad.h
@@ -48,16 +48,17 @@
 #include <QLinearGradient>
 #include <QVector>
 
+//! [0]
 class FlippablePad : public RoundRectItem
 {
 public:
     FlippablePad(const QSize &size, QGraphicsItem *parent = 0);
 
-    RoundRectItem *iconAt(int x, int y) const;
+    RoundRectItem *iconAt(int column, int row) const;
 
 private:
-    int columns;
     QVector<QVector<RoundRectItem *> > iconGrid;
 };
+//! [0]
 
 #endif // FLIPPABLEPAD_H
diff --git a/examples/graphicsview/padnavigator/main.cpp b/examples/graphicsview/padnavigator/main.cpp
index 6d148bb..984b976 100644
--- a/examples/graphicsview/padnavigator/main.cpp
+++ b/examples/graphicsview/padnavigator/main.cpp
@@ -43,6 +43,7 @@
 
 #include <QtGui/QtGui>
 
+//! [0]
 int main(int argc, char *argv[])
 {
     QApplication app(argc, argv);
@@ -53,3 +54,4 @@ int main(int argc, char *argv[])
 
     return app.exec();
 }
+//! [0]
diff --git a/examples/graphicsview/padnavigator/padnavigator.cpp b/examples/graphicsview/padnavigator/padnavigator.cpp
index 456b3f4..b1d19f6 100644
--- a/examples/graphicsview/padnavigator/padnavigator.cpp
+++ b/examples/graphicsview/padnavigator/padnavigator.cpp
@@ -42,175 +42,213 @@
 #include "flippablepad.h"
 #include "padnavigator.h"
 #include "splashitem.h"
-#include "ui_form.h"
 
 #include <QtGui/QtGui>
 #ifndef QT_NO_OPENGL
 #include <QtOpenGL/QtOpenGL>
 #endif
 
+//! [0]
 PadNavigator::PadNavigator(const QSize &size, QWidget *parent)
     : QGraphicsView(parent)
 {
-    // Prepare splash item
+//! [0]
+//! [1]
+    // Splash item
     SplashItem *splash = new SplashItem;
     splash->setZValue(1);
+//! [1]
 
-    // Prepare pad item
+//! [2]
+    // Pad item
     FlippablePad *pad = new FlippablePad(size);
     QGraphicsRotation *flipRotation = new QGraphicsRotation(pad);
-    flipRotation->setAxis(Qt::YAxis);
     QGraphicsRotation *xRotation = new QGraphicsRotation(pad);
-    xRotation->setAxis(Qt::YAxis);
     QGraphicsRotation *yRotation = new QGraphicsRotation(pad);
+    flipRotation->setAxis(Qt::YAxis);
+    xRotation->setAxis(Qt::YAxis);
     yRotation->setAxis(Qt::XAxis);
     pad->setTransformations(QList<QGraphicsTransform *>()
                             << flipRotation
                             << xRotation << yRotation);
+//! [2]
 
-    // Prepare backitem
-    form = new Ui_Form;
-    QWidget *widget = new QWidget;
-    form->setupUi(widget);
-    form->hostName->setFocus();
+//! [3]
+    // Back (proxy widget) item
     QGraphicsProxyWidget *backItem = new QGraphicsProxyWidget(pad);
-    backItem->setCacheMode(QGraphicsItem::ItemCoordinateCache);
+    QWidget *widget = new QWidget;
+    form.setupUi(widget);
+    form.hostName->setFocus();
     backItem->setWidget(widget);
+    backItem->setVisible(false);
+    backItem->setFocus();
+    backItem->setCacheMode(QGraphicsItem::ItemCoordinateCache);
+    const QRectF r = backItem->rect();
     backItem->setTransform(QTransform()
                            .rotate(180, Qt::YAxis)
-                           .translate(-backItem->rect().width()/2, -backItem->rect().height()/2));
-    backItem->setFocus();
-    backItem->setVisible(false);
+                           .translate(-r.width()/2, -r.height()/2));
+//! [3]
 
-    // Prepare selection item
+//! [4]
+    // Selection item
     RoundRectItem *selectionItem = new RoundRectItem(QRectF(-60, -60, 120, 120),
                                                      Qt::gray, pad);
     selectionItem->setZValue(0.5);
+//! [4]
 
-    // Selection animation setup
+//! [5]
+    // Splash animations
+    QPropertyAnimation *smoothSplashMove = new QPropertyAnimation(splash, "y");
+    QPropertyAnimation *smoothSplashOpacity = new QPropertyAnimation(splash, "opacity");
+    smoothSplashMove->setEasingCurve(QEasingCurve::InQuad);
+    smoothSplashMove->setDuration(250);
+    smoothSplashOpacity->setDuration(250);
+//! [5]
+
+//! [6]
+    // Selection animation
     QPropertyAnimation *smoothXSelection = new QPropertyAnimation(selectionItem, "x");
-    smoothXSelection->setDuration(125);
-    smoothXSelection->setEasingCurve(QEasingCurve::InOutQuad);
     QPropertyAnimation *smoothYSelection = new QPropertyAnimation(selectionItem, "y");
-    smoothYSelection->setDuration(125);
-    smoothYSelection->setEasingCurve(QEasingCurve::InOutQuad);
     QPropertyAnimation *smoothXRotation = new QPropertyAnimation(xRotation, "angle");
-    smoothXRotation->setDuration(125);
-    smoothXRotation->setEasingCurve(QEasingCurve::InOutQuad);
     QPropertyAnimation *smoothYRotation = new QPropertyAnimation(yRotation, "angle");
+    smoothXSelection->setDuration(125);
+    smoothYSelection->setDuration(125);
+    smoothXRotation->setDuration(125);
     smoothYRotation->setDuration(125);
+    smoothXSelection->setEasingCurve(QEasingCurve::InOutQuad);
+    smoothYSelection->setEasingCurve(QEasingCurve::InOutQuad);
+    smoothXRotation->setEasingCurve(QEasingCurve::InOutQuad);
     smoothYRotation->setEasingCurve(QEasingCurve::InOutQuad);
-    QPropertyAnimation *smoothScale = new QPropertyAnimation(pad, "scale");
-    smoothScale->setDuration(500);
-    smoothScale->setKeyValueAt(0, qVariantValue<qreal>(1.0));
-    smoothScale->setKeyValueAt(0.5, qVariantValue<qreal>(0.7));
-    smoothScale->setKeyValueAt(1, qVariantValue<qreal>(1.0));
-    smoothScale->setEasingCurve(QEasingCurve::InOutQuad);
+//! [6]
 
+//! [7]
     // Flip animation setup
     QPropertyAnimation *smoothFlipRotation = new QPropertyAnimation(flipRotation, "angle");
+    QPropertyAnimation *smoothFlipScale = new QPropertyAnimation(pad, "scale");
+    QPropertyAnimation *smoothFlipXRotation = new QPropertyAnimation(xRotation, "angle");
+    QPropertyAnimation *smoothFlipYRotation = new QPropertyAnimation(yRotation, "angle");
+    QParallelAnimationGroup *flipAnimation = new QParallelAnimationGroup(this);
+    smoothFlipScale->setDuration(500);
     smoothFlipRotation->setDuration(500);
+    smoothFlipXRotation->setDuration(500);
+    smoothFlipYRotation->setDuration(500);
+    smoothFlipScale->setEasingCurve(QEasingCurve::InOutQuad);
     smoothFlipRotation->setEasingCurve(QEasingCurve::InOutQuad);
-    QPropertyAnimation *flipSmoothXRotation = new QPropertyAnimation(xRotation, "angle");
-    flipSmoothXRotation->setDuration(500);
-    flipSmoothXRotation->setEasingCurve(QEasingCurve::InOutQuad);
-    QPropertyAnimation *flipSmoothYRotation = new QPropertyAnimation(yRotation, "angle");
-    flipSmoothYRotation->setDuration(500);
-    flipSmoothYRotation->setEasingCurve(QEasingCurve::InOutQuad);
-    QPropertyAnimation *setBackItemVisibleAnim = new QPropertyAnimation(backItem, "visible");
-    setBackItemVisibleAnim->setDuration(0);
-    QPropertyAnimation *setSelectionItemVisibleAnim = new QPropertyAnimation(selectionItem, "visible");
-    setSelectionItemVisibleAnim->setDuration(0);
-    QPropertyAnimation *setFillAnim = new QPropertyAnimation(pad, "fill");
-    setFillAnim->setDuration(0);
-    QSequentialAnimationGroup *setVisibleAnimation = new QSequentialAnimationGroup;
-    setVisibleAnimation->addPause(250);
-    setVisibleAnimation->addAnimation(setBackItemVisibleAnim);
-    setVisibleAnimation->addAnimation(setSelectionItemVisibleAnim);
-    setVisibleAnimation->addAnimation(setFillAnim);
-    QParallelAnimationGroup *flipAnimation = new QParallelAnimationGroup(this);
+    smoothFlipXRotation->setEasingCurve(QEasingCurve::InOutQuad);
+    smoothFlipYRotation->setEasingCurve(QEasingCurve::InOutQuad);
+    smoothFlipScale->setKeyValueAt(0, qVariantValue<qreal>(1.0));
+    smoothFlipScale->setKeyValueAt(0.5, qVariantValue<qreal>(0.7));
+    smoothFlipScale->setKeyValueAt(1, qVariantValue<qreal>(1.0));
     flipAnimation->addAnimation(smoothFlipRotation);
-    flipAnimation->addAnimation(smoothScale);
-    flipAnimation->addAnimation(flipSmoothXRotation);
-    flipAnimation->addAnimation(flipSmoothYRotation);
-    flipAnimation->addAnimation(setVisibleAnimation);
+    flipAnimation->addAnimation(smoothFlipScale);
+    flipAnimation->addAnimation(smoothFlipXRotation);
+    flipAnimation->addAnimation(smoothFlipYRotation);
+//! [7]
 
-    QPropertyAnimation *smoothSplashMove = new QPropertyAnimation(splash, "y");
-    smoothSplashMove->setEasingCurve(QEasingCurve::InQuad);
-    smoothSplashMove->setDuration(250);
-    QPropertyAnimation *smoothSplashOpacity = new QPropertyAnimation(splash, "opacity");
-    smoothSplashOpacity->setDuration(250);
+//! [8]
+    // Flip animation delayed property assignment
+    QSequentialAnimationGroup *setVariablesSequence = new QSequentialAnimationGroup;
+    QPropertyAnimation *setFillAnimation = new QPropertyAnimation(pad, "fill");
+    QPropertyAnimation *setBackItemVisibleAnimation = new QPropertyAnimation(backItem, "visible");
+    QPropertyAnimation *setSelectionItemVisibleAnimation = new QPropertyAnimation(selectionItem, "visible");
+    setFillAnimation->setDuration(0);
+    setBackItemVisibleAnimation->setDuration(0);
+    setSelectionItemVisibleAnimation->setDuration(0);
+    setVariablesSequence->addPause(250);
+    setVariablesSequence->addAnimation(setBackItemVisibleAnimation);
+    setVariablesSequence->addAnimation(setSelectionItemVisibleAnimation);
+    setVariablesSequence->addAnimation(setFillAnimation);
+    flipAnimation->addAnimation(setVariablesSequence);
+//! [8]
 
+//! [9]
     // Build the state machine
     QStateMachine *stateMachine = new QStateMachine(this);
     QState *splashState = new QState(stateMachine);
     QState *frontState = new QState(stateMachine);
     QHistoryState *historyState = new QHistoryState(frontState);
     QState *backState = new QState(stateMachine);
+//! [9]
+//! [10]
+    frontState->assignProperty(pad, "fill", false);
     frontState->assignProperty(splash, "opacity", 0.0);
-    frontState->assignProperty(flipRotation, "angle", qVariantValue<qreal>(0.0));
     frontState->assignProperty(backItem, "visible", false);
+    frontState->assignProperty(flipRotation, "angle", qVariantValue<qreal>(0.0));
     frontState->assignProperty(selectionItem, "visible", true);
-    frontState->assignProperty(pad, "fill", false);
-    backState->assignProperty(flipRotation, "angle", qVariantValue<qreal>(180.0));
+    backState->assignProperty(pad, "fill", true);
+    backState->assignProperty(backItem, "visible", true);
     backState->assignProperty(xRotation, "angle", qVariantValue<qreal>(0.0));
     backState->assignProperty(yRotation, "angle", qVariantValue<qreal>(0.0));
+    backState->assignProperty(flipRotation, "angle", qVariantValue<qreal>(180.0));
     backState->assignProperty(selectionItem, "visible", false);
-    backState->assignProperty(backItem, "visible", true);
-    backState->assignProperty(pad, "fill", true);
     stateMachine->addDefaultAnimation(smoothXRotation);
     stateMachine->addDefaultAnimation(smoothYRotation);
     stateMachine->addDefaultAnimation(smoothXSelection);
     stateMachine->addDefaultAnimation(smoothYSelection);
     stateMachine->setInitialState(splashState);
+//! [10]
 
+//! [11]
     // Transitions
     QEventTransition *anyKeyTransition = new QEventTransition(this, QEvent::KeyPress, splashState);
     anyKeyTransition->setTargetState(frontState);
     anyKeyTransition->addAnimation(smoothSplashMove);
     anyKeyTransition->addAnimation(smoothSplashOpacity);
+//! [11]
 
-    QKeyEventTransition *enterTransition = new QKeyEventTransition(this, QEvent::KeyPress, Qt::Key_Enter, backState);
+//! [12]
+    QKeyEventTransition *enterTransition = new QKeyEventTransition(this, QEvent::KeyPress,
+                                                                   Qt::Key_Enter, backState);
+    QKeyEventTransition *returnTransition = new QKeyEventTransition(this, QEvent::KeyPress,
+                                                                    Qt::Key_Return, backState);
+    QKeyEventTransition *backEnterTransition = new QKeyEventTransition(this, QEvent::KeyPress,
+                                                                       Qt::Key_Enter, frontState);
+    QKeyEventTransition *backReturnTransition = new QKeyEventTransition(this, QEvent::KeyPress,
+                                                                        Qt::Key_Return, frontState);
     enterTransition->setTargetState(historyState);
-    QKeyEventTransition *returnTransition = new QKeyEventTransition(this, QEvent::KeyPress, Qt::Key_Return, backState);
     returnTransition->setTargetState(historyState);
-    QKeyEventTransition *backEnterTransition = new QKeyEventTransition(this, QEvent::KeyPress, Qt::Key_Enter, frontState);
     backEnterTransition->setTargetState(backState);
-    QKeyEventTransition *backReturnTransition = new QKeyEventTransition(this, QEvent::KeyPress, Qt::Key_Return, frontState);
     backReturnTransition->setTargetState(backState);
     enterTransition->addAnimation(flipAnimation);
     returnTransition->addAnimation(flipAnimation);
     backEnterTransition->addAnimation(flipAnimation);
     backReturnTransition->addAnimation(flipAnimation);
+//! [12]
 
-    // Substates, one for each icon
+//! [13]
+    // Create substates for each icon; store in temporary grid.
     int columns = size.width();
     int rows = size.height();
     QVector< QVector< QState * > > stateGrid;
     stateGrid.resize(rows);
     for (int y = 0; y < rows; ++y) {
         stateGrid[y].resize(columns);
-        for (int x = 0; x < columns; ++x) {
-            QState *state = new QState(frontState);
-            stateGrid[y][x] = state;
-        }
+        for (int x = 0; x < columns; ++x)
+            stateGrid[y][x] = new QState(frontState);
     }
     frontState->setInitialState(stateGrid[0][0]);
     selectionItem->setPos(pad->iconAt(0, 0)->pos());
+//! [13]
 
+//! [14]
     // Enable key navigation using state transitions
     for (int y = 0; y < rows; ++y) {
         for (int x = 0; x < columns; ++x) {
             QState *state = stateGrid[y][x];
-            QKeyEventTransition *rightTransition = new QKeyEventTransition(this, QEvent::KeyPress, Qt::Key_Right, state);
+            QKeyEventTransition *rightTransition = new QKeyEventTransition(this, QEvent::KeyPress,
+                                                                           Qt::Key_Right, state);
+            QKeyEventTransition *leftTransition = new QKeyEventTransition(this, QEvent::KeyPress,
+                                                                          Qt::Key_Left, state);
+            QKeyEventTransition *downTransition = new QKeyEventTransition(this, QEvent::KeyPress,
+                                                                          Qt::Key_Down, state);
+            QKeyEventTransition *upTransition = new QKeyEventTransition(this, QEvent::KeyPress,
+                                                                        Qt::Key_Up, state);
             rightTransition->setTargetState(stateGrid[y][(x + 1) % columns]);
-            QKeyEventTransition *leftTransition = new QKeyEventTransition(this, QEvent::KeyPress, Qt::Key_Left, state);
             leftTransition->setTargetState(stateGrid[y][((x - 1) + columns) % columns]);
-            QKeyEventTransition *downTransition = new QKeyEventTransition(this, QEvent::KeyPress, Qt::Key_Down, state);
             downTransition->setTargetState(stateGrid[(y + 1) % rows][x]);
-            QKeyEventTransition *upTransition = new QKeyEventTransition(this, QEvent::KeyPress, Qt::Key_Up, state);
             upTransition->setTargetState(stateGrid[((y - 1) + rows) % rows][x]);
-
+//! [14]
+//! [15]
             RoundRectItem *icon = pad->iconAt(x, y);
             state->assignProperty(xRotation, "angle", -icon->x() / 6.0);
             state->assignProperty(yRotation, "angle", icon->y() / 6.0);
@@ -219,47 +257,51 @@ PadNavigator::PadNavigator(const QSize &size, QWidget *parent)
             frontState->assignProperty(icon, "visible", true);
             backState->assignProperty(icon, "visible", false);
 
-            QPropertyAnimation *setVisibleAnim = new QPropertyAnimation(icon, "visible");
-            setVisibleAnim->setDuration(0);
-            setVisibleAnimation->addAnimation(setVisibleAnim);
+            QPropertyAnimation *setIconVisibleAnimation = new QPropertyAnimation(icon, "visible");
+            setIconVisibleAnimation->setDuration(0);
+            setVariablesSequence->addAnimation(setIconVisibleAnimation);
         }
     }
+//! [15]
 
-    // Setup scene
+//! [16]
+    // Scene
     QGraphicsScene *scene = new QGraphicsScene(this);
     scene->setBackgroundBrush(QPixmap(":/images/blue_angle_swirl.jpg"));
     scene->setItemIndexMethod(QGraphicsScene::NoIndex);
     scene->addItem(pad);
     scene->setSceneRect(scene->itemsBoundingRect());
     setScene(scene);
+//! [16]
 
-    // Adjust splash item
-    splash->setPos(-splash->boundingRect().width() / 2, scene->sceneRect().top());
+//! [17]
+    // Adjust splash item to scene contents
+    const QRectF sbr = splash->boundingRect();
+    splash->setPos(-sbr.width() / 2, scene->sceneRect().top() - 2);
     frontState->assignProperty(splash, "y", splash->y() - 100.0);
     scene->addItem(splash);
+//! [17]
 
-    // Setup view
+//! [18]
+    // View
     setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     setMinimumSize(50, 50);
     setViewportUpdateMode(FullViewportUpdate);
     setCacheMode(CacheBackground);
-    setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform
-                   | QPainter::TextAntialiasing);
+    setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform | QPainter::TextAntialiasing);
 #ifndef QT_NO_OPENGL
     setViewport(new QGLWidget(QGLFormat(QGL::SampleBuffers)));
 #endif
 
     stateMachine->start();
+//! [18]
 }
 
-PadNavigator::~PadNavigator()
-{
-    delete form;
-}
-
+//! [19]
 void PadNavigator::resizeEvent(QResizeEvent *event)
 {
     QGraphicsView::resizeEvent(event);
     fitInView(scene()->sceneRect(), Qt::KeepAspectRatio);
 }
+//! [19]
diff --git a/examples/graphicsview/padnavigator/padnavigator.h b/examples/graphicsview/padnavigator/padnavigator.h
index c79a13c..03a1ea2 100644
--- a/examples/graphicsview/padnavigator/padnavigator.h
+++ b/examples/graphicsview/padnavigator/padnavigator.h
@@ -43,23 +43,25 @@
 #define PADNAVIGATOR_H
 
 #include <QGraphicsView>
+#include "ui_form.h"
 
 class QState;
 class QStateMachine;
 class Ui_Form;
 
+//! [0]
 class PadNavigator : public QGraphicsView
 {
     Q_OBJECT
 public:
     explicit PadNavigator(const QSize &size, QWidget *parent = 0);
-    ~PadNavigator();
 
 protected:
     void resizeEvent(QResizeEvent *event);
 
 private:
-    Ui_Form *form;
+    Ui_Form form;
 };
+//! [0]
 
 #endif // PADNAVIGATOR_H
diff --git a/examples/graphicsview/padnavigator/roundrectitem.cpp b/examples/graphicsview/padnavigator/roundrectitem.cpp
index 2141e9a..7a0b279 100644
--- a/examples/graphicsview/padnavigator/roundrectitem.cpp
+++ b/examples/graphicsview/padnavigator/roundrectitem.cpp
@@ -43,34 +43,39 @@
 
 #include <QtGui/QtGui>
 
+//! [0]
 RoundRectItem::RoundRectItem(const QRectF &bounds, const QColor &color,
                              QGraphicsItem *parent)
-    : QGraphicsObject(parent), fillRect(false), color(color), bounds(bounds)
+    : QGraphicsObject(parent), fillRect(false), bounds(bounds)
 {
     gradient.setStart(bounds.topLeft());
     gradient.setFinalStop(bounds.bottomRight());
     gradient.setColorAt(0, color);
     gradient.setColorAt(1, color.dark(200));
-
     setCacheMode(ItemCoordinateCache);
 }
+//! [0]
 
+//! [1]
 QPixmap RoundRectItem::pixmap() const
 {
     return pix;
 }
-
 void RoundRectItem::setPixmap(const QPixmap &pixmap)
 {
     pix = pixmap;
     update();
 }
+//! [1]
 
+//! [2]
 QRectF RoundRectItem::boundingRect() const
 {
     return bounds.adjusted(0, 0, 2, 2);
 }
+//! [2]
 
+//! [3]
 void RoundRectItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
                           QWidget *widget)
 {
@@ -79,25 +84,31 @@ void RoundRectItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *opt
     painter->setPen(Qt::NoPen);
     painter->setBrush(QColor(0, 0, 0, 64));
     painter->drawRoundRect(bounds.translated(2, 2));
+//! [3]
+//! [4]
     if (fillRect)
         painter->setBrush(QApplication::palette().brush(QPalette::Window));
     else
         painter->setBrush(gradient);
     painter->setPen(QPen(Qt::black, 1));
     painter->drawRoundRect(bounds);
+//! [4]
+//! [5]
     if (!pix.isNull()) {
         painter->scale(1.95, 1.95);
         painter->drawPixmap(-pix.width() / 2, -pix.height() / 2, pix);
     }
 }
+//! [5]
 
+//! [6]
 bool RoundRectItem::fill() const
 {
     return fillRect;
 }
-
 void RoundRectItem::setFill(bool fill)
 {
     fillRect = fill;
     update();
 }
+//! [6]
diff --git a/examples/graphicsview/padnavigator/roundrectitem.h b/examples/graphicsview/padnavigator/roundrectitem.h
index ae5fb4c..bc58cec 100644
--- a/examples/graphicsview/padnavigator/roundrectitem.h
+++ b/examples/graphicsview/padnavigator/roundrectitem.h
@@ -45,6 +45,7 @@
 #include <QGraphicsObject>
 #include <QLinearGradient>
 
+//! [0]
 class RoundRectItem : public QGraphicsObject
 {
     Q_OBJECT
@@ -61,13 +62,15 @@ public:
 
     bool fill() const;
     void setFill(bool fill);
+//! [0]
 
+//! [1]
 private:
     QPixmap pix;
     bool fillRect;
-    QColor color;
     QRectF bounds;
     QLinearGradient gradient;
 };
+//! [1]
 
 #endif // ROUNDRECTITEM_H
diff --git a/examples/graphicsview/padnavigator/splashitem.cpp b/examples/graphicsview/padnavigator/splashitem.cpp
index e609656..cd7074a 100644
--- a/examples/graphicsview/padnavigator/splashitem.cpp
+++ b/examples/graphicsview/padnavigator/splashitem.cpp
@@ -43,20 +43,25 @@
 
 #include <QtGui/QtGui>
 
-SplashItem::SplashItem(QGraphicsItem *parent) :
-    QGraphicsObject(parent)
+//! [0]
+SplashItem::SplashItem(QGraphicsItem *parent)
+    : QGraphicsObject(parent)
 {
     text = tr("Welcome to the Pad Navigator Example. You can use the"
               " keyboard arrows to navigate the icons, and press enter"
               " to activate an item. Press any key to begin.");
     setCacheMode(DeviceCoordinateCache);
 }
+//! [0]
 
+//! [1]
 QRectF SplashItem::boundingRect() const
 {
     return QRectF(0, 0, 400, 175);
 }
+//! [1]
 
+//! [2]
 void SplashItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
                        QWidget *widget)
 {
@@ -76,3 +81,4 @@ void SplashItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option
     painter->setFont(font);
     painter->drawText(textRect, flags, text);
 }
+//! [2]
diff --git a/examples/graphicsview/padnavigator/splashitem.h b/examples/graphicsview/padnavigator/splashitem.h
index 9d57653..98c4a1f 100644
--- a/examples/graphicsview/padnavigator/splashitem.h
+++ b/examples/graphicsview/padnavigator/splashitem.h
@@ -44,6 +44,7 @@
 
 #include <QGraphicsObject>
 
+//! [0]
 class SplashItem : public QGraphicsObject
 {
     Q_OBJECT
@@ -56,5 +57,6 @@ public:
 private:
     QString text;
 };
+//! [0]
 
 #endif // SPLASHITEM_H