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Qt/Embedded Virtual Framebuffer
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===============================
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Please note that the qvfb program needs to be compiled with the X11 version
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of Qt.
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The virtual frame buffer allows a Qt/Embedded program to be developed on your
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desktop machine, without switching between consoles and X11. The virtual
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framebuffer consists of a shared memory region (the virtual frame buffer)
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and a utility to display the framebuffer in a window. The display is updated
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periodically, so you will see discrete snapshots of the framebuffer rather
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than each individual drawing operation. For this reason drawing problems
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such as flickering may not be apparent until the program is run using a real
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framebuffer.
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To use the virtual framebuffer:
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1. Ensure QT_NO_QWS_VFB is not set in qconfig.h (when you configure Qt,
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add the -qvfb option).
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2. Start qvfb (qvfb should be compiled as a normal Qt/X11 application,
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NOT as a Qt/Embedded application!).
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3. Start a Qt/Embedded server (i.e. construct QApplication with
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QApplication::GuiServer flag, or run a client with the -qws option).
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qvfb supports the following command line options:
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[-width width] the width of the virtual framebuffer (default: 240).
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[-height height] the height of the virtual framebuffer (default: 320).
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[-depth depth] the depth of the virtual framebuffer (1,4,8 or 32, default: 8).
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[-nocursor] do not display the X11 cursor in the framebuffer window.
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[-qwsdisplay] the Qt/Embedded display ID, e.g. -qwsdisplay :1 (default :0).
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[-skin skinfile] tells qvfb to load a skin file, e.g. -skin pda.skin
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Please refer to the file "pda.skin" for an example of what a skin file looks like.
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The format for skin files is:
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Image filename of skin with buttons in their up positions
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Image filename of skin with buttons in their down positions
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X offset of top left corner of the virtual screen on the skin image
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Y offset of top left corner of the virtual screen on the skin image
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Width of the virtual screen on the skin image
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Height of the virtual screen on the skin image
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Transparancy level of the Virtual Frame Buffer
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Number of defined button regions
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Then for each button region the format is:
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Button identifier
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Qt scan codes to generate for the button
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Top left X coordinate of the button region
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Top left Y coordinate of the button region
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Bottom right X coordinate of the button region
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Bottom right Y coordinate of the button region
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The virtual framebuffer is a development tool only. No security issues have
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been considered in the virtual framebuffer design. It should not be used
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in a production environment and QT_NO_QWS_VFB should always be in force
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in production libraries.
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