Fix docs for Drag and Drop examples

Change-Id: Ic1622b64603f7634b697bd7d8412dcc9f1a8c3fa
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>

2 files changed, 0 insertions, 360 deletions

diff --git a/doc/src/examples/fridgemagnets.qdoc b/doc/src/examples/fridgemagnets.qdoc
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--- a/doc/src/examples/fridgemagnets.qdoc
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-/****************************************************************************
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-
-/*!
-    \example draganddrop/fridgemagnets
-    \title Fridge Magnets Example
-
-    The Fridge Magnets example shows how to supply more than one type
-    of MIME-encoded data with a drag and drop operation.
-
-    \image fridgemagnets-example.png
-
-    With this application the user can play around with a collection
-    of fridge magnets, using drag and drop to form new sentences from
-    the words on the magnets. The example consists of two classes:
-
-    \list
-        \li \c DragLabel is a custom widget representing one
-           single fridge magnet.
-        \li \c DragWidget provides the main application window.
-    \endlist
-
-    We will first take a look at the \c DragLabel class, then we will
-    examine the \c DragWidget class.
-
-    \section1 DragLabel Class Definition
-
-    Each fridge magnet is represented by an instance of the \c
-    DragLabel class:
-
-    \snippet examples/draganddrop/fridgemagnets/draglabel.h 0
-
-    Each instance of this QLabel subclass will be used to display an
-    pixmap generated from a text string. Since we cannot store both
-    text and a pixmap in a standard label, we declare a private variable
-    to hold the original text, and we define an additional member
-    function to allow it to be accessed.
-
-    \section1 DragLabel Class Implementation
-
-    In the \c DragLabel constructor, we first create a QImage object
-    on which we will draw the fridge magnet's text and frame:
-
-    \snippet examples/draganddrop/fridgemagnets/draglabel.cpp 0
-
-    Its size depends on the current font size, and its format is
-    QImage::Format_ARGB32_Premultiplied; i.e., the image is stored
-    using a premultiplied 32-bit ARGB format (0xAARRGGBB).
-
-    We then construct a font object that uses the application's
-    default font, and set its style strategy. The style strategy tells
-    the font matching algorithm what type of fonts should be used to
-    find an appropriate default family. The QFont::ForceOutline forces
-    the use of outline fonts.
-
-    To draw the text and frame onto the image, we use the QPainter
-    class. QPainter provides highly optimized methods to do most of
-    the drawing GUI programs require. It can draw everything from
-    simple lines to complex shapes like pies and chords. It can also
-    draw aligned text and pixmaps.
-
-    \snippet examples/draganddrop/fridgemagnets/draglabel.cpp 1
-
-    A painter can be activated by passing a paint device to the
-    constructor, or by using the \l{QPainter::}{begin()} method as we
-    do in this example. The \l{QPainter::}{end()} method deactivates
-    it. Note that the latter function is called automatically upon
-    destruction when the painter is actived by its constructor. The
-    QPainter::Antialiasing render hint ensures that the paint engine
-    will antialias the edges of primitives if possible.
-
-    When the painting is done, we convert our image to a pixmap using
-    QPixmap's \l {QPixmap::}{fromImage()} method. This method also
-    takes an optional flags argument, and converts the given image to
-    a pixmap using the specified flags to control the conversion (the
-    flags argument is a bitwise-OR of the Qt::ImageConversionFlags;
-    passing 0 for flags sets all the default options).
-
-    \snippet examples/draganddrop/fridgemagnets/draglabel.cpp 2
-
-    Finally, we set the label's \l{QLabel::pixmap}{pixmap property}
-    and store the label's text for later use.
-
-    \e{Note that setting the pixmap clears any previous content, including
-    any text previously set using QLabel::setText(), and disables
-    the label widget's buddy shortcut, if any.}
-
-    \section1 DragWidget Class Definition
-
-    The \c DragWidget class inherits QWidget, providing support for
-    drag and drop operations:
-
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.h 0
-
-    To make the widget responsive to drag and drop operations, we simply
-    reimplement the \l{QWidget::}{dragEnterEvent()},
-    \l{QWidget::}{dragMoveEvent()} and \l{QWidget::}{dropEvent()} event
-    handlers inherited from QWidget.
-
-    We also reimplement \l{QWidget::}{mousePressEvent()} to make the
-    widget responsive to mouse clicks. This is where we will write code
-    to start drag and drop operations.
-
-    \section1 DragWidget Class Implementation
-
-    In the constructor, we first open the file containing the words on
-    our fridge magnets:
-
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 0
-
-    QFile is an I/O device for reading and writing text and binary
-    files and resources, and may be used by itself or in combination
-    with QTextStream or QDataStream. We have chosen to read the
-    contents of the file using the QTextStream class that provides a
-    convenient interface for reading and writing text.
-
-    We then create the fridge magnets. As long as there is data (the
-    QTextStream::atEnd() method returns true if there is no more data
-    to be read from the stream), we read one line at a time using
-    QTextStream's \l {QTextStream::}{readLine()} method.
-
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 1
-
-    For each line, we create a \c DragLabel object using the read line
-    as text, we calculate its position and ensure that it is visible by
-    calling the QWidget::show() method. We set the Qt::WA_DeleteOnClose
-    attribute on each label to ensure that any unused labels will be
-    deleted; we will need to create new labels and delete old ones when
-    they are dragged around, and this ensures that the example does not
-    leak memory.
-
-    We also set the \c FridgeMagnets widget's palette, minimum size
-    and window title.
-
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 2
-
-    Finally, to enable our user to move the fridge magnets around, we
-    must also set the \c FridgeMagnets widget's
-    \l{QWidget::acceptDrops}{acceptDrops} property.
-
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 3
-
-    Setting this property to true announces to the system that this
-    widget \e may be able to accept drop events (events that are sent
-    when drag and drop actions are completed). Later, we will
-    implement the functions that ensure that the widget accepts the
-    drop events it is interested in.
-
-    \section2 Dragging
-
-    Let's take a look at the \l{QWidget::}{mousePressEvent()} event
-    handler, where drag and drop operations begin:
-
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 13
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 14
-
-    Mouse events occur when a mouse button is pressed or released
-    inside a widget, or when the mouse cursor is moved. By
-    reimplementing the \l{QWidget::}{mousePressEvent()} method we
-    ensure that we will receive mouse press events for the widget
-    containing the fridge magnets.
-
-    Whenever we receive such an event, we first check to see if the
-    position of the click coincides with one of the labels. If not,
-    we simply return.
-
-    If the user clicked a label, we determine the position of the
-    \e{hot spot} (the position of the click relative to the top-left
-    corner of the label). We create a byte array to store the label's
-    text and the hot spot, and we use a QDataStream object to stream
-    the data into the byte array.
-
-    With all the information in place, we create a new QMimeData object.
-    As mentioned above, QMimeData objects associate the data that they
-    hold with the corresponding MIME types to ensure that information
-    can be safely transferred between applications. The
-    \l{QMimeData::}{setData()} method sets the data associated with a
-    given MIME type. In our case, we associate our item data with the
-    custom \c application/x-fridgemagnet type.
-
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 15
-
-    Note that we also associate the magnet's text with the
-    \c text/plain MIME type using QMimeData's \l{QMimeData::}{setText()}
-    method. Below, we will see how our widget detects both these MIME
-    types with its event handlers.
-
-    Finally, we create a QDrag object. It is the QDrag class that
-    handles most of the details of a drag and drop operation,
-    providing support for MIME-based drag and drop data transfer. The
-    data to be transferred by the drag and drop operation is contained
-    in a QMimeData object. When we call QDrag's
-    \l{QDrag::}{setMimeData()} method the ownership of our item data is
-    transferred to the QDrag object.
-
-    We call the \l{QDrag::}{setPixmap()} function to set the pixmap used
-    to represent the data during the drag and drop operation.
-    Typically, this pixmap shows an icon that represents the MIME type
-    of the data being transferred, but any pixmap can be used. In this
-    example, we simply use the pixmap used by the label itself to make
-    it look like the fridge magnet itself is being moved.
-
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 16
-
-    We also specify the cursor's hot spot, its position relative to the
-    top-level corner of the drag pixmap, to be the point we calculated
-    above. This makes the process of dragging the label feel more natural
-    because the cursor always points to the same place on the label
-    during the drag operation. 
-
-    We start the drag operation using QDrag's \l{QDrag::}{exec()} function,
-    requesting that the magnet is copied when the drag is completed.
-
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 17
-
-    The function returns the drop action actually performed by the user
-    (this can be either a copy or a move action in this case); if this
-    action is equal to Qt::MoveAction we will close the activated
-    fridge magnet widget because we will create a new one to replace it
-    (see the \l{drop}{dropEvent()} implementation). Otherwise, if
-    the drop is outside our main widget, we simply show the widget in
-    its original position.
-
-    \section2 Dropping
-
-    When a a drag and drop action enters our widget, we will receive a
-    drag enter \e event. QDragEnterEvent inherits most of its
-    functionality from QDragMoveEvent, which in turn inherits most of
-    its functionality from QDropEvent. Note that we must accept this
-    event in order to receive the drag move events that are sent while
-    the drag and drop action is in progress. The drag enter event is
-    always immediately followed by a drag move event.
-
-    In our \c dragEnterEvent() implementation, we first determine
-    whether we support the event's MIME type or not:
-
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 4
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 5
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 6
-
-    If the type is \c application/x-fridgemagnet and the event
-    origins from any of this application's fridge magnet widgets, we
-    first set the event's drop action using the
-    QDropEvent::setDropAction() method. An event's drop action is the
-    action to be performed on the data by the target. Qt::MoveAction
-    indicates that the data is moved from the source to the target.
-
-    Then we call the event's \l {QDragMoveEvent::}{accept()} method to
-    indicate that we have handled the event. In general, unaccepted
-    events might be propagated to the parent widget. If the event
-    origins from any other widget, we simply accept the proposed
-    action.
-
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 7
-
-    We also accept the proposed action if the event's MIME type is \c
-    text/plain, i.e., if QMimeData::hasText() returns true. If the
-    event has any other type, on the other hand, we call the event's
-    \l {QDragMoveEvent::}{ignore()} method allowing the event to be
-    propagated further.
-
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 8
-
-    Drag move events occur when the cursor enters a widget, when it
-    moves within the widget, and when a modifier key is pressed on the
-    keyboard while the widget has focus. Our widget will receive drag
-    move events repeatedly while a drag is within its boundaries. We
-    reimplement the \l {QWidget::}{dragMoveEvent()} method, and
-    examine the event in the exact same way as we did with drag enter
-    events.
-
-    Note that the \l{QWidget::}{dropEvent()} event handler behaves
-    slightly differently: We first get hold of the event's MIME
-    data.
-
-    \target drop
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 9
-
-    The QMimeData class provides a container for data that
-    records information about its MIME type. QMimeData objects
-    associate the data that they hold with the corresponding MIME
-    types to ensure that information can be safely transferred between
-    applications, and copied around within the same application.
-
-    We retrieve the data associated with the \c application/x-fridgemagnet
-    MIME type using a data stream in order to create a new \c DragLabel
-    object.
-
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 10
-
-    The QDataStream class provides serialization of binary data to a
-    QIODevice (a data stream is a binary stream of encoded information
-    which is completely independent of the host computer's operating
-    system, CPU or byte order).
-
-    Finally, we create a label and move it to the event's position:
-
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 11
-
-    If the source of the event is also the widget receiving the
-    drop event, we set the event's drop action to Qt::MoveAction and
-    call the event's \l{QDragMoveEvent::}{accept()}
-    method. Otherwise, we simply accept the proposed action. This
-    means that labels are moved rather than copied in the same
-    window. However, if we drag a label to a second instance of the
-    Fridge Magnets example, the default action is to copy it, leaving
-    the original in the first instance.
-
-    If the event's MIME type is \c text/plain (i.e., if
-    QMimeData::hasText() returns true) we retrieve its text and split
-    it into words. For each word we create a new \c DragLabel action,
-    and show it at the event's position plus an offset depending on
-    the number of words in the text. In the end we accept the proposed
-    action. This lets the user drop selected text from a text editor or
-    Web browser onto the widget to add more fridge magnets.
-
-    \snippet examples/draganddrop/fridgemagnets/dragwidget.cpp 12
-
-    If the event has any other type, we call the event's
-    \l{QDragMoveEvent::}{ignore()} method allowing the event to be
-    propagated further.
-
-    \section1 Summary
-
-    We set our main widget's \l{QWidget::}{acceptDrops} property
-    and reimplemented QWidget's \l{QWidget::}{dragEnterEvent()},
-    \l{QWidget::}{dragMoveEvent()} and \l{QWidget::}{dropEvent()} event
-    handlers to support content dropped on our widget.
-
-    In addition, we reimplemented the \l{QWidget::}{mousePressEvent()}
-    function to let the user pick up fridge magnets in the first place.
-
-    Because data is communicated using drag and drop operations and
-    encoded using MIME types, you can run more than one instance of this
-    example, and transfer magnets between them.
-*/
diff --git a/doc/src/images/fridgemagnets-example.png b/doc/src/images/fridgemagnets-example.png
deleted file mode 100644
index 9adb572afc..0000000000
--- a/doc/src/images/fridgemagnets-example.png
+++ /dev/null