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/*!
    \page qtopiacore-qvfb.html

    \title Qtopia Core's Virtual Framebuffer
    \ingroup qtopiacore

    \l {Qtopia Core} applications write directly to the framebuffer,
    eliminating the need for the X Window System and saving
    memory. For development and debugging purposes, a virtual framebuffer
    can be used, allowing \l {Qtopia Core} programs to be developed on a
    desktop machine, without switching between consoles and X11.

    QVFb is an X11 application supplied with Qt/X11 that provides a
    virtual framebuffer for Qtopia Core to use. To use it, you need to
    \l{Installing Qt/X11}{configure and install Qt/X11} according

    \image qtopiacore-virtualframebuffer.png

    The virtual framebuffer emulates a framebuffer using a shared
    memory region and the \c qvfb tool to display the framebuffer in a
    window. The \c qvfb tool also supports a feature known as a skin
    which can be used to change the look and feel of the display. The
    tool is located in Qt's \c tools/qvfb directory, and provides
    several additional features accessible through its \gui File and
    \gui View menus.

    Please note that the virtual framebuffer is a development tool
    only. No security issues have been considered in the virtual
    framebuffer design. It should be avoided in a production
    environment, i.e. do not configure production libraries with the
    \c -qvfb option.

    \tableofcontents

    \section1 Displaying the Virtual Framebuffer

    To run the \c qvfb tool displaying the virtual framebuffer, the
    \l {Qtopia Core} library must be configured and compiled with the \c
    -qvfb option:

    \code
         cd path/to/Qtopia/Core
         ./configure -qvfb
         make
    \endcode

    Then compile and run the \c qvfb tool as a normal Qt/X11
    application (i.e. do \e not compile it as a \l {Qtopia Core}
    application):

    \code
        cd path/to/Qt/tools/qvfb
        make
        ./qvfb
    \endcode

    The \c qvfb application supports the following command line
    options:

    \table
    \header \o Option \o Description
    \row
    \o \c {-width <value>}
    \o The width of the virtual framebuffer (default: 240).
    \row
    \o \c {-height <value>}
    \o The height of the virtual framebuffer (default: 320).
    \row
    \o \c {-depth <value>}
    \o The depth of the virtual framebuffer (1, 8 or 32; default: 8).
    \row
    \o \c -nocursor
    \o Do not display the X11 cursor in the framebuffer window.
    \row
    \o \c {-qwsdisplay <:id>}
    \o The \l {Qtopia Core} display ID (default: 0).
    \row
    \o \c {-skin <name>.skin}
    \o The preferred skin. Note that the skin must be located in Qt's
    \c /tools/qvfb/ directory.
    \row
    \o \c {-zoom <factor>}
    \o Scales the application view with the given factor.

    \endtable

    \section2 Skins

    A skin is a set of XML and pixmap files that tells the vitual
    framebuffer what it should look like and how it should behave; a
    skin can change the unrealistic default display into a display
    that is similar to the target device. To access the \c qvfb tool's
    menus when a skin is activated, right-click over the display.

    Note that a skin can have buttons which (when clicked) send
    signals to the Qtopia application running inside the virtual
    framebuffer, just as would happen on a real device.

    \table 100%
    \row
        \o
        \bold {Target Device Environment}

        The \c qvfb tool provides various skins by default, allowing
        the user to view their application in an environment similar
        to their target device. The provided skins are:

        \list
            \o ClamshellPhone
            \o pda
            \o PDAPhone
            \o QtopiaPDA
            \o QtopiaPhone-Advanced
            \o QtopiaPhone-Simple
            \o SmartPhone
            \o SmartPhone2
            \o SmartPhoneWithButtons
            \o TouchscreenPhone
            \o Trolltech-Keypad
            \o Trolltech-Touchscreen
        \endlist

        In addition, it is possible to create custom skins.

        \o \image qtopiacore-phone.png
        \o \image qtopiacore-pda.png
    \endtable

    \bold {Creating Custom Skins}

    The XML and pixmap files specifying a custom skin must be located
    in subdirectory of the Qt's \c /tools/qvfb directory, called \c
    /customskin.skin. See the ClamshellPhone skin for an example of the
    file structure:

    \code
        cd path/to/Qt/tools/qvfb/ClamshellPhone.skin/
    \endcode

    The \c /ClamshellPhone.skin directory contains the following files:

    \list
        \o \c ClamshellPhone.skin
        \o \c ClamshellPhone1-5.png
        \o \c ClamshellPhone1-5-pressed.png
        \o \c ClamshellPhone1-5-closed.png
        \o \c defaultbuttons.conf (only necessary for \l Qtopia)
    \endlist

    Note that the \c defaultbuttons.conf file is only necessary if the
    skin is supposed to be used with \l Qtopia (The file customizes
    the launch screen applications, orders the soft keys and provides
    input method hints). See the \l Qtopia documentation for more
    information.

    \table 100%
    \header
    \o {3,1} The ClamshellPhone Skin
    \row
    \o {3,1}

    \code
        [SkinFile]
        Up=ClamshellPhone1-5.png
        Down=ClamshellPhone1-5-pressed.png
        Closed=ClamshellPhone1-5-closed.png
        Screen=72 84 176 208
        Areas=22

        "Power"     0x0100000a 205 563 249 586
        "1"         0x0031      62 414 119 438
        "2"         0x0032     130 414 189 438
        "3"         0x0033     198 413 257 438
        "4"         0x0034      54 444 117 470
        "5"         0x0035     128 444 189 471
        "6"         0x0036     202 444 264 471
        "7"         0x0037      47 477 113 507
        "8"         0x0038     126 477 190 507
        "9"         0x0039     205 478 270 509
        "*"         0x002a      39 515 110 552
        "0"         0x0030     122 515 195 553
        "#"         0x0023     207 516 280 553
        "Context1"  0x01100000 137 360 108 383 123 410 90 409  60 387  63 378
                               100 362
        "Back"      0x01000061 184 361 206 376 213 387 197 410 226 410 256 392
                               258 381 244 369
        "Backspace" 0x01000003  68 563 113 587
        "Select"    0x01010000 160 391 172 390 181 386 184 381 180 377 173
                               373 165 372 155 372 145 375 138 378 136
                               382 138 387 147 390
        "Left"      0x1000012  141 390 136 385 136 381 143 375 132 371 120
                               380 121 393 129 401
        "Down"      0x1000015  143 389 130 402 162 412 191 404 175 390
        "Right"     0x1000014  186 370 176 375 184 382 182 387 175 390 190 404
                               201 396 202 375
        "Up"        0x1000013  133 370 143 374 176 374 185 370 169 362 149 362
        "Flip"      0x01100006  98 325 225 353
    \endcode

    The \c ClamShellPhone.skin file quoted above, specifies three
    pixmaps: One for the normal skin (\c Up), one for the activated
    skin (\c Down) and one for the closed skin (\c Closed). In
    addition, it is possible to specify a pixmap for the cursor (using
    a \c Cursor variable).

    The file also specifies the screen size (\c Screen) and the number
    of available buttons (\c Areas). Then it describes the buttons
    themselves; each button is specified by its name, keycode and
    coordinates.

    The coordinates are a list of at least 2 points in clockwise order
    that define a shape for the button; a click inside this shape will
    be treated as a click on that button. While pressed, the pixels
    for the button are redrawn from the activated skin.

    \row
    \row
    \o
    \image qtopiacore-clamshellphone-closed.png The ClamshellPhone Skin (closed)
    \o
    \image qtopiacore-clamshellphone.png The ClamshellPhone Skin
    \o
    \image qtopiacore-clamshellphone-pressed.png The ClamshellPhone Skin (pressed)
    \row
    \o \c ClamshellPhone1-5-closed.png
    \o \c ClamshellPhone1-5.png
    \o \c ClamshellPhone1-5-pressed.png
    \endtable

    \section2 The File Menu

    \image qtopiacore-qvfbfilemenu.png

    The \gui File menu allows the user to configure the virtual
    framebuffer display (\gui File|Configure...), save a snapshot of
    the framebuffer contents (\gui {File|Save Image...}) and record
    the movements in the framebuffer (\gui File|Animation...).

    When choosing the \gui File|Configure menu item, the \c qvfb tool
    provides a configuration dialog allowing the user to customize the
    display of the virtual framebuffer. The user can modify the size
    and depth as well as the Gamma values, and also select the
    preferred skin (i.e. making the virtual framebuffer simulate the
    target device environment). In addition, it is possible to emulate
    a touch screen and a LCD screen.

    Note that when configuring (except when changing the Gamma values
    only), any applications using the virtual framebuffer will be
    terminated.

    \section2 The View Menu

    \image qtopiacore-qvfbviewmenu.png

    The \gui View menu allows the user to modify the target's refresh
    rate (\gui {View|Refresh Rate...}), making \c qvfb check for
    updated regions more or less frequently.

    The regions of the display that have changed are updated
    periodically, i.e. the virtual framebuffer is displaying discrete
    snapshots of the framebuffer rather than each individual drawing
    operation. For this reason drawing problems such as flickering may
    not be apparent until the program is run using a real framebuffer.
    If little drawing is being done, the framebuffer will not show any
    updates between drawing events. If an application is displaying an
    animation, the updates will be frequent, and the application and
    \c qvfb will compete for processor time.

    The \gui View menu also allows the user to zoom the view of the
    application  (\gui {View|Zoom *}).

    \section1 Running Applications Using the Virtual Framebuffer

    Once the virtual framebuffer (the \c qvfb application) is running,
    it is ready for use: Start a server application (i.e. construct a
    QApplication object with the QApplication::GuiServer flag or use
    the \c -qws command line parameter. See the \l {Running Qtopia
    Core Applications}{running applications} documentation for
    details). For example:

    \code
        cd path/to/Qtopia/Core/examples/widgets/analogclock
        make
        ./analogclock -qws
    \endcode

    Note that as long as the virtual framebuffer is running and the
    current \l {Qtopia Core} configuration supports \c qvfb, \l
    {Qtopia Core} will automatically detect it and use it by
    default. Alternatively, the \c -display option can be used to
    specify the virtual framebuffer driver. For example:

    \code
        cd path/to/Qtopia/Core/examples/widgets/analogclock
        make
        ./analogclock -qws -display QVFb:0
    \endcode

    \warning If \c qvfb is not running (or the current \l {Qtopia
    Core} configuration doesn't support it) and the driver is not
    explicitly specified, \l {Qtopia Core} will write to the real
    framebuffer and the X11 display will be corrupted.
*/
