classpvideochannel.html

pwlib开发文档

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<p>
Open the specified device for playing or recording. The device name is platform specific and is as returned in the GetDevices() function.
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<dl compact><dt><b>Returns: </b></dt><dd>
 TRUE if the video device is valid for playing/recording. </dl><dl compact><dt><b>Parameters: </b></dt><dd>
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<tr><td valign=top><em>dir</em>&nbsp;</td><td>
Name of video driver/device Video I/O direction </td></tr>
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</dl>    </td>
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<a name="a2" doxytag="PVideoChannel::Read"></a><p>
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          <td class="md" nowrap valign="top"> virtual BOOL PVideoChannel::Read </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="md" nowrap valign="top">void *&nbsp;</td>
          <td class="mdname" nowrap>&nbsp; <em>buf</em>, </td>
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          <td></td>
          <td class="md" nowrap>PINDEX&nbsp;</td>
          <td class="mdname" nowrap>&nbsp; <em>len</em></td>
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          <td class="md">)&nbsp;</td>
          <td class="md" colspan="2"><code> [virtual]</code></td>
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<p>
Low level read from the channel. This function may block until the requested number of characters were read or the read timeout was reached. The <a class="el" href="classPChannel.html#z49_3">GetLastReadCount()</a> function returns the actual number of bytes read.
<p>
The <a class="el" href="classPChannel.html#z55_2">GetErrorCode()</a> function should be consulted after <a class="el" href="classPVideoChannel.html#a2">Read()</a> returns FALSE to determine what caused the failure.
<p>
<dl compact><dt><b>Returns: </b></dt><dd>
 TRUE indicates that at least one character was read from the channel. FALSE means no bytes were read due to timeout or some other I/O error. </dl>
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Reimplemented from <a class="el" href="classPChannel.html#z49_2">PChannel</a>.    </td>
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<a name="a4" doxytag="PVideoChannel::Redraw"></a><p>
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          <td class="md" nowrap valign="top"> virtual BOOL PVideoChannel::Redraw </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="md" nowrap valign="top">const void *&nbsp;</td>
          <td class="mdname1" valign="top" nowrap>&nbsp; <em>frame</em>          </td>
          <td class="md" valign="top">)&nbsp;</td>
          <td class="md" nowrap><code> [virtual]</code></td>
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<p>
Cause the referenced data to be drawn to the  previously defined media     </td>
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<a name="a18" doxytag="PVideoChannel::RestrictAccess"></a><p>
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          <td class="md" nowrap valign="top"> void PVideoChannel::RestrictAccess </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="mdname1" valign="top" nowrap>&nbsp;          </td>
          <td class="md" valign="top">)&nbsp;</td>
          <td class="md" nowrap></td>
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<p>
Restrict others from using this video channel.     </td>
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<a name="a8" doxytag="PVideoChannel::SetGrabberFrameSize"></a><p>
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          <td class="md" nowrap valign="top"> virtual void PVideoChannel::SetGrabberFrameSize </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="md" nowrap valign="top">int&nbsp;</td>
          <td class="mdname" nowrap>&nbsp; <em>_width</em>, </td>
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          <td></td>
          <td class="md" nowrap>int&nbsp;</td>
          <td class="mdname" nowrap>&nbsp; <em>_height</em></td>
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          <td class="md">)&nbsp;</td>
          <td class="md" colspan="2"><code> [virtual]</code></td>
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<p>
Specifiy the width and height of the video stream, which is to be extracted from the previously specified device.     </td>
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<a name="a7" doxytag="PVideoChannel::SetRenderFrameSize"></a><p>
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          <td class="md" nowrap valign="top"> virtual void PVideoChannel::SetRenderFrameSize </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="md" nowrap valign="top">int&nbsp;</td>
          <td class="mdname" nowrap>&nbsp; <em>_width</em>, </td>
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          <td></td>
          <td></td>
          <td class="md" nowrap>int&nbsp;</td>
          <td class="mdname" nowrap>&nbsp; <em>_height</em></td>
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          <td class="md">)&nbsp;</td>
          <td class="md" colspan="2"><code> [virtual]</code></td>
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<p>
Specifiy the width and height of the video stream, which is to be rendered onto the previously specified device.     </td>
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<a name="a20" doxytag="PVideoChannel::ToggleVFlipInput"></a><p>
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          <td class="md" nowrap valign="top"> BOOL PVideoChannel::ToggleVFlipInput </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="mdname1" valign="top" nowrap>&nbsp;          </td>
          <td class="md" valign="top">)&nbsp;</td>
          <td class="md" nowrap></td>
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Toggle the vertical flip state of the video grabber.     </td>
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<a name="a3" doxytag="PVideoChannel::Write"></a><p>
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          <td class="md" nowrap valign="top"> BOOL PVideoChannel::Write </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="md" nowrap valign="top">const void *&nbsp;</td>
          <td class="mdname" nowrap>&nbsp; <em>buf</em>, </td>
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          <td></td>
          <td></td>
          <td class="md" nowrap>PINDEX&nbsp;</td>
          <td class="mdname" nowrap>&nbsp; <em>len</em></td>
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          <td></td>
          <td class="md">)&nbsp;</td>
          <td class="md" colspan="2"><code> [virtual]</code></td>
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<p>
Low level write to the channel, which is data to be rendered to the  local video display device. 
<p>
Reimplemented from <a class="el" href="classPChannel.html#z51_2">PChannel</a>.    </td>
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<hr><h2>Member Data Documentation</h2>
<a name="n4" doxytag="PVideoChannel::accessMutex"></a><p>
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          <td class="md" nowrap valign="top"> <a class="el" href="classPMutex.html">PMutex</a> PVideoChannel::accessMutex<code> [protected]</code>
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<p>
For displaying video on the screen.
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<a name="n1" doxytag="PVideoChannel::deviceName"></a><p>
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          <td class="md" nowrap valign="top"> <a class="el" href="classPString.html">PString</a> PVideoChannel::deviceName<code> [protected]</code>
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<a name="q0" doxytag="PVideoChannel::dictMutex"></a><p>
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          <td class="md" nowrap valign="top"> <a class="el" href="classPMutex.html">PMutex</a> PVideoChannel::dictMutex<code> [static, protected]</code>
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<a name="n0" doxytag="PVideoChannel::direction"></a><p>
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          <td class="md" nowrap valign="top"> <a class="el" href="classPVideoChannel.html#z471_0">Directions</a> PVideoChannel::direction<code> [protected]</code>
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<a name="n2" doxytag="PVideoChannel::mpInput"></a><p>
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          <td class="md" nowrap valign="top"> <a class="el" href="classPVideoInputDevice.html">PVideoInputDevice</a>* PVideoChannel::mpInput<code> [protected]</code>
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Specified video device name, eg /dev/video0.
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<a name="n3" doxytag="PVideoChannel::mpOutput"></a><p>
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          <td class="md" nowrap valign="top"> <a class="el" href="classPVideoOutputDevice.html">PVideoOutputDevice</a>* PVideoChannel::mpOutput<code> [protected]</code>
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<p>
For grabbing video from the camera.
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<hr>The documentation for this class was generated from the following file:<ul>
<li><a class="el" href="video_8h-source.html">video.h</a></ul>
<hr><address style="align: right;"><small>Generated on Wed Sep 29 22:44:20 2004 for PWLib by
<a href="http://www.doxygen.org/index.html">
<img src="doxygen.png" alt="doxygen" align="middle" border=0 
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