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authorTimothy Pearson <kb9vqf@pearsoncomputing.net>2011-07-10 15:24:15 -0500
committerTimothy Pearson <kb9vqf@pearsoncomputing.net>2011-07-10 15:24:15 -0500
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+/****************************************************************************
+**
+** Qt/Embedded Virtual Framebuffer
+**
+** Copyright (C) 1992-2008 Trolltech ASA. All rights reserved.
+**
+** This file is part of the Qt GUI Toolkit.
+**
+** This file may be used under the terms of the GNU General
+** Public License versions 2.0 or 3.0 as published by the Free
+** Software Foundation and appearing in the files LICENSE.GPL2
+** and LICENSE.GPL3 included in the packaging of this file.
+** Alternatively you may (at your option) use any later version
+** of the GNU General Public License if such license has been
+** publicly approved by Trolltech ASA (or its successors, if any)
+** and the KDE Free Qt Foundation.
+**
+** Please review the following information to ensure GNU General
+** Public Licensing requirements will be met:
+** http://trolltech.com/products/qt/licenses/licensing/opensource/.
+** If you are unsure which license is appropriate for your use, please
+** review the following information:
+** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
+** or contact the sales department at sales@trolltech.com.
+**
+** This file may be used under the terms of the Q Public License as
+** defined by Trolltech ASA and appearing in the file LICENSE.QPL
+** included in the packaging of this file. Licensees holding valid Qt
+** Commercial licenses may use this file in accordance with the Qt
+** Commercial License Agreement provided with the Software.
+**
+** This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+** INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE. Trolltech reserves all rights not granted
+** herein.
+**
+**********************************************************************/
+
+/*! \page emb-qvfb.html
+
+\title Qt/Embedded Virtual Framebuffer
+
+The virtual framebuffer allows Qt/Embedded programs to be developed on
+a desktop machine, without switching between consoles and X11.
+
+The virtual framebuffer is located in \c $QTDIR/tools/qvfb.
+
+\section1 Using the Virtual Framebuffer
+
+\list 1
+\i Configure Qt/Embedded with the \c -qvfb argument and compile the library:
+ \code
+ ./configure -qvfb
+ make
+ \endcode
+\i Compile \c qvfb as a normal Qt/X11 application and run it. Do \e not
+ compile it as a Qt/Embedded application.
+\i Start a Qt/Embedded master application (i.e., construct
+ QApplication with the QApplication::GuiServer flag or use the \c
+ -qws command line parameter). You can specify to the server that
+ you wish to use the virtual framebuffer driver, e.g.:
+ \code
+ masterapp -qws -display QVFb:0
+ \endcode
+\i Qt/Embedded will autodetect qvfb, so you can omit the \c -display
+ command line parameter if you know that qvfb is running, and that
+ the Qt/Embedded library supports qvfb. (If this is not the case,
+ Qt/Embedded will write to the real framebuffer, and your X11
+ display will be corrupted.)
+
+\endlist
+
+\c qvfb supports the following command line options:
+
+\table
+\header \i Option \i Meaning
+\row
+\i \c -width \e width
+\i the width of the virtual framebuffer (default: 240).
+\row
+\i \c -height \e height
+\i the height of the virtual framebuffer (default: 320).
+\row
+\i \c -depth \e depth
+\i the depth of the virtual framebuffer (1, 8 or 32; default: 8).
+\row
+\i \c -nocursor
+\i do not display the X11 cursor in the framebuffer window.
+\row
+\i \c -qwsdisplay \e :id
+\i the Qt/Embedded display id to provide (default: :0).
+\endtable
+
+\section1 Virtual Framebuffer Design
+
+The virtual framebuffer emulates a framebuffer using a shared memory region
+(the virtual frame buffer) and a utility to display the framebuffer in a
+window (\c qvfb). The regions of the display that have changed are 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.
+
+The target refresh rate can be set via the <b>View|Refresh Rate</b>
+menu item. This will cause \c qvfb to check for updated regions more
+frequently. The rate is a target only. 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, then the application and \c qvfb will compete for
+processor time.
+
+Mouse and keyboard events are passed to the Qt/Embedded master process via
+named pipes.
+
+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; do not configure production libraries with \c -qvfb.
+
+*/