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.TH "qvfb" "1" "3.0.3" "Troll Tech AS, Norway." "" |
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.SH "NAME" |
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.LP |
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qvfb \- Virtual framebuffer for Qt |
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.SH "DESCRIPTION" |
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.LP |
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The virtual framebuffer allows Qt/Embedded programs to be |
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developed on your desktop machine, without switching |
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between consoles and X11. |
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|
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Start a Qt/Embedded master application (i.e., construct |
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QApplication with QApplication::GuiServer flag or use the |
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\-qws command line parameter). You will need to specify to |
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the server that you wish to use the virtual framebuffer |
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driver, e.g.: |
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|
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widgets \-qws \-display QVFb:0 |
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You may prefer to set the QWS_DISPLAY environment |
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variable to be QVFb:0. |
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qvfb supports the following command line options: |
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\-width width: the width of the virtual framebuffer |
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(default: 240). |
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\-height height: the height of the virtual framebuffer |
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(default: 320). |
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\-depth depth: the depth of the virtual framebuffer (1, 8 |
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or 32; default: 8). |
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\-nocursor: do not display the X11 cursor in the |
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framebuffer window. |
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\-qwsdisplay :id the Qt/Embedded display id to provide |
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(default: 0). |
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|
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Virtual Framebuffer Design |
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The virtual framebuffer emulates a framebuffer using a |
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shared memory region (the virtual frame buffer) and a |
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utility to display the framebuffer in a window (qvfb). |
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The regions of the display that have changed are updated |
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periodically, so you will see discrete snapshots of the |
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framebuffer rather than each individual drawing |
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operation. For this reason drawing problems such as |
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flickering may not be apparent until the program is run |
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using a real framebuffer. |
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The target refresh rate can be set via the "View|Refresh |
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Rate" menu item. This will cause qvfb to check for |
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updated regions more quickly. The rate is a target only. |
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If little drawing is being done, the framebuffer will not |
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show any updates between drawing events. If an |
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application is displaying an animation the updates will |
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be frequent, and the application and qvfb will compete |
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for processor time. |
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|
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Mouse and keyboard events are passed to the Qt/Embedded |
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master process via named pipes. |
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The virtual framebuffer is a development tool only. No |
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security issues have been considered in the virtual |
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framebuffer design. It should be avoided in a production |
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environment; QT_NO_QWS_VFB should always be defined in |
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production libraries. |
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.SH "AUTHORS" |
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.LP |
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TrollTech <http://www.trolltech.com/> |