Qt for Embedded Linux Virtual Framebuffer
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The virtual frame buffer allows a Qt for Embedded Linux program to be developed
on your desktop machine, without switching between consoles and X11.  The virtual
framebuffer consists of a shared memory region (the virtual frame buffer)
and a utility to display the framebuffer in a window.  The display is updated
periodically, so you will see 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.

To use the virtual framebuffer:

1. Ensure QT_NO_QWS_VFB is not set in qconfig.h (when you configure Qt,
    add the -qvfb option).
2. Start qvfb (qvfb should be compiled as a normal Qt for X11 application,
    NOT as a Qt for Embedded Linux application!).
3. Start a Qt for Embedded Linux server (i.e. construct QApplication with
   QApplication::GuiServer flag, or run a client with the -qws option).

qvfb supports the following command line options:

[-width width]   the width of the virtual framebuffer (default: 240).
[-height height] the height of the virtual framebuffer (default: 320).
[-depth depth]   the depth of the virtual framebuffer (1,4,8 or 32, default: 8).
[-nocursor]      do not display the X11 cursor in the framebuffer window.
[-qwsdisplay]    the Qt for Embedded Linux display ID, e.g. -qwsdisplay :1 (default :0).
[-skin skinfile] tells qvfb to load a skin file, e.g. -skin pda.skin

Please refer to the file "pda.skin" as an example of what a skin file looks like.
The format for skin files is:
    Image filename of skin with buttons in their up positions
    Image filename of skin with buttons in their down positions
    X offset of top left corner of the virtual screen on the skin image
    Y offset of top left corner of the virtual screen on the skin image
    Width of the virtual screen on the skin image
    Height of the virtual screen on the skin image
    Number of defined button regions
Then for each button region the format is:
    Button identifier
    Qt scan codes to generate for the button
    Top left X coordinate of the button region
    Top left Y coordinate of the button region
    Bottom right X coordinate of the button region
    Bottom right Y coordinate of the button region

The virtual framebuffer is a development tool only.  No security issues have
been considered in the virtual framebuffer design.  It should not be used
in a production environment and QT_NO_QWS_VFB should always be in force
in production libraries.