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  • Committer: Bazaar Package Importer
  • Author(s): Fathi Boudra
  • Date: 2011-06-10 11:22:47 UTC
  • mfrom: (1.1.6 upstream) (2.1.4 sid)
  • Revision ID: james.westby@ubuntu.com-20110610112247-0i1019vvmzaq6p86
Tags: 6.0.0-1
http://bugs.debian.org/624107
http://bugs.debian.org/604379
http://bugs.debian.org/626868
http://bugs.debian.org/626567
* New upstream release (Closes: #624107):
  - drop Qt3 support. (Closes: #604379, #626868)
* Register documentation with doc-base. (Closes: #626567)
* Drop patches:
  - 01_makefiles.diff
  - 02_add_missing_warnings.diff
  - 03_qwt_branch_pull_r544.diff
* Add qwt_install_paths.patch to fix the hardcoded installation paths.
* Update debian/control:
  - drop libqt3-mt-dev build dependency.
  - bump Standards-Version to 3.9.2 (no changes).
  - drop Qt3 related packages.
  - due to bump soname (and as we dropper Qt3 support):
    - libqwt5-qt4-dev -> libqwt-dev
    - libqwt5-qt4 -> libqwt6
    - libqwt5-doc -> libqwt-doc
* Update debian/copyright file.
* Update debian/rules: drop Qt3 packages support.

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qwt/doc/html/class_qwt_plot_raster_item.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html><head><meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
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<title>Qwt User&#39;s Guide: QwtPlotRasterItem Class Reference</title>
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<link href="tabs.css" rel="stylesheet" type="text/css">
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<link href="doxygen.css" rel="stylesheet" type="text/css">
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</head><body>
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<!-- Generated by Doxygen 1.5.8 -->
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<div class="navigation" id="top">
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  <div class="tabs">
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    <ul>
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      <li><a href="index.html"><span>Main&nbsp;Page</span></a></li>
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      <li><a href="pages.html"><span>Related&nbsp;Pages</span></a></li>
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      <li class="current"><a href="annotated.html"><span>Classes</span></a></li>
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      <li><a href="files.html"><span>Files</span></a></li>
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    </ul>
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  </div>
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  <div class="tabs">
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    <ul>
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      <li><a href="annotated.html"><span>Class&nbsp;List</span></a></li>
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      <li><a href="classes.html"><span>Class&nbsp;Index</span></a></li>
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      <li><a href="hierarchy.html"><span>Class&nbsp;Hierarchy</span></a></li>
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      <li><a href="functions.html"><span>Class&nbsp;Members</span></a></li>
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    </ul>
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  </div>
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</div>
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<div class="contents">
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<h1>QwtPlotRasterItem Class Reference</h1><!-- doxytag: class="QwtPlotRasterItem" --><!-- doxytag: inherits="QwtPlotItem" -->A class, which displays raster data.  
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<a href="#_details">More...</a>
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<p>
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<code>#include &lt;<a class="el" href="qwt__plot__rasteritem_8h-source.html">qwt_plot_rasteritem.h</a>&gt;</code>
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<p>
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<div class="dynheader">
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Inheritance diagram for QwtPlotRasterItem:</div>
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<div class="dynsection">
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<p><center><img src="class_qwt_plot_raster_item__inherit__graph.png" border="0" usemap="#_qwt_plot_raster_item__inherit__map" alt="Inheritance graph"></center>
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<map name="_qwt_plot_raster_item__inherit__map">
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<area shape="rect" href="class_qwt_plot_spectrogram.html" title="A plot item, which displays a spectrogram." alt="" coords="17,232,164,256"><area shape="rect" href="class_qwt_plot_item.html" title="Base class for items on the plot canvas." alt="" coords="43,83,139,107"><area shape="rect" href="class_qwt_legend_item_manager.html" title="Abstract API to bind plot items to the legend." alt="" coords="7,8,175,32"></map>
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<center><font size="2">[<a href="graph_legend.html">legend</a>]</font></center></div>
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<p>
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<a href="class_qwt_plot_raster_item-members.html">List of all members.</a><table border="0" cellpadding="0" cellspacing="0">
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<tr><td></td></tr>
43
 
<tr><td colspan="2"><br><h2>Public Types</h2></td></tr>
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<tr><td class="memItemLeft" nowrap align="right" valign="top">enum &nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_plot_raster_item.html#94929fc4c31c3dab75ee5adcac2d57b0">CachePolicy</a> { <br>
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&nbsp;&nbsp;<b>NoCache</b>, 
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<br>
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&nbsp;&nbsp;<b>PaintCache</b>, 
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<br>
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&nbsp;&nbsp;<b>ScreenCache</b>
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<br>
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 }</td></tr>
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<tr><td colspan="2"><br><h2>Public Member Functions</h2></td></tr>
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<tr><td class="memItemLeft" nowrap align="right" valign="top">&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_plot_raster_item.html#2149c1d6b71c607027345a9a51ef3314">QwtPlotRasterItem</a> (const QString &amp;title=QString::null)</td></tr>
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<tr><td class="memItemLeft" nowrap align="right" valign="top">&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_plot_raster_item.html#f487c6abc8e95200d4537d1373f96be5">QwtPlotRasterItem</a> (const <a class="el" href="class_qwt_text.html">QwtText</a> &amp;title)</td></tr>
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58
 
<tr><td class="memItemLeft" nowrap align="right" valign="top">virtual&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_plot_raster_item.html#2715233827c346ab15504dc75d6e9714">~QwtPlotRasterItem</a> ()</td></tr>
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60
 
<tr><td class="memItemLeft" nowrap align="right" valign="top">void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_plot_raster_item.html#14f2ab8ec0994384e6269f869c352273">setAlpha</a> (int alpha)</td></tr>
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<tr><td class="memItemLeft" nowrap align="right" valign="top">int&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_plot_raster_item.html#96b2faa0bc0fe086bff1abe72bcb2016">alpha</a> () const </td></tr>
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<tr><td class="memItemLeft" nowrap align="right" valign="top">void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_plot_raster_item.html#31f74199f7e333c2683b0f18289e4c7f">setCachePolicy</a> (<a class="el" href="class_qwt_plot_raster_item.html#94929fc4c31c3dab75ee5adcac2d57b0">CachePolicy</a>)</td></tr>
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<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="class_qwt_plot_raster_item.html#94929fc4c31c3dab75ee5adcac2d57b0">CachePolicy</a>&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_plot_raster_item.html#c953db5d88084f416b4dbc3ca8a323f3">cachePolicy</a> () const </td></tr>
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<tr><td class="memItemLeft" nowrap align="right" valign="top">void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_plot_raster_item.html#547ce4d8d031b230226cfbd509ef65b5">invalidateCache</a> ()</td></tr>
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<tr><td class="memItemLeft" nowrap align="right" valign="top">virtual void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_plot_raster_item.html#81b062af415a8df33262f23768fd71ad">draw</a> (QPainter *p, const <a class="el" href="class_qwt_scale_map.html">QwtScaleMap</a> &amp;xMap, const <a class="el" href="class_qwt_scale_map.html">QwtScaleMap</a> &amp;yMap, const QRect &amp;rect) const </td></tr>
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<tr><td class="memItemLeft" nowrap align="right" valign="top">virtual QSize&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_plot_raster_item.html#610342c1ff21beed110f6454b705368c">rasterHint</a> (const QwtDoubleRect &amp;) const </td></tr>
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<tr><td colspan="2"><br><h2>Protected Member Functions</h2></td></tr>
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<tr><td class="memItemLeft" nowrap align="right" valign="top">virtual QImage&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_plot_raster_item.html#8767aea6b99f44109e8490e8ee2c3cbe">renderImage</a> (const <a class="el" href="class_qwt_scale_map.html">QwtScaleMap</a> &amp;xMap, const <a class="el" href="class_qwt_scale_map.html">QwtScaleMap</a> &amp;yMap, const QwtDoubleRect &amp;area) const =0</td></tr>
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77
 
</table>
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<hr><a name="_details"></a><h2>Detailed Description</h2>
79
 
A class, which displays raster data. 
80
 
<p>
81
 
Raster data is a grid of pixel values, that can be represented as a QImage. It is used for many types of information like spectrograms, cartograms, geographical maps ...<p>
82
 
Often a plot has several types of raster data organized in layers. ( f.e a geographical map, with weather statistics ). Using <a class="el" href="class_qwt_plot_raster_item.html#14f2ab8ec0994384e6269f869c352273" title="Set an alpha value for the raster data.">setAlpha()</a> raster items can be stacked easily.<p>
83
 
<a class="el" href="class_qwt_plot_raster_item.html" title="A class, which displays raster data.">QwtPlotRasterItem</a> is only implemented for images of the following formats: QImage::Format_Indexed8, QImage::Format_ARGB32.<p>
84
 
<dl class="see" compact><dt><b>See also:</b></dt><dd><a class="el" href="class_qwt_plot_spectrogram.html" title="A plot item, which displays a spectrogram.">QwtPlotSpectrogram</a> </dd></dl>
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<hr><h2>Member Enumeration Documentation</h2>
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<a class="anchor" name="94929fc4c31c3dab75ee5adcac2d57b0"></a><!-- doxytag: member="QwtPlotRasterItem::CachePolicy" ref="94929fc4c31c3dab75ee5adcac2d57b0" args="" -->
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<div class="memitem">
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<div class="memproto">
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      <table class="memname">
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        <tr>
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          <td class="memname">enum <a class="el" href="class_qwt_plot_raster_item.html#94929fc4c31c3dab75ee5adcac2d57b0">QwtPlotRasterItem::CachePolicy</a>          </td>
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        </tr>
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      </table>
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</div>
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<div class="memdoc">
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<p>
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<ul>
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<li>NoCache<br>
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 <a class="el" href="class_qwt_plot_raster_item.html#8767aea6b99f44109e8490e8ee2c3cbe">renderImage()</a> is called, whenever the item has to be repainted</li><li>PaintCache<br>
101
 
 <a class="el" href="class_qwt_plot_raster_item.html#8767aea6b99f44109e8490e8ee2c3cbe">renderImage()</a> is called, whenever the image cache is not valid, or the scales, or the size of the canvas has changed. This type of cache is only useful for improving the performance of hide/show operations. All other situations are already handled by the plot canvas cache.</li><li>ScreenCache<br>
102
 
 The screen cache is an image in size of the screen. As long as the scales don't change the target image is scaled from the cache. This might improve the performance when resizing the plot widget, but suffers from scaling effects.</li></ul>
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<p>
104
 
The default policy is NoCache 
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</div>
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</div><p>
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<hr><h2>Constructor &amp; Destructor Documentation</h2>
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<a class="anchor" name="2149c1d6b71c607027345a9a51ef3314"></a><!-- doxytag: member="QwtPlotRasterItem::QwtPlotRasterItem" ref="2149c1d6b71c607027345a9a51ef3314" args="(const QString &amp;title=QString::null)" -->
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<div class="memitem">
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<div class="memproto">
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      <table class="memname">
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        <tr>
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          <td class="memname">QwtPlotRasterItem::QwtPlotRasterItem           </td>
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          <td>(</td>
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          <td class="paramtype">const QString &amp;&nbsp;</td>
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          <td class="paramname"> <em>title</em> = <code>QString::null</code>          </td>
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          <td>&nbsp;)&nbsp;</td>
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          <td><code> [explicit]</code></td>
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        </tr>
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      </table>
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</div>
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<div class="memdoc">
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<p>
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Constructor. 
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<p>
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</div>
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</div><p>
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<a class="anchor" name="f487c6abc8e95200d4537d1373f96be5"></a><!-- doxytag: member="QwtPlotRasterItem::QwtPlotRasterItem" ref="f487c6abc8e95200d4537d1373f96be5" args="(const QwtText &amp;title)" -->
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<div class="memitem">
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<div class="memproto">
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      <table class="memname">
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        <tr>
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          <td class="memname">QwtPlotRasterItem::QwtPlotRasterItem           </td>
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          <td>(</td>
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          <td class="paramtype">const <a class="el" href="class_qwt_text.html">QwtText</a> &amp;&nbsp;</td>
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          <td class="paramname"> <em>title</em>          </td>
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          <td>&nbsp;)&nbsp;</td>
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          <td><code> [explicit]</code></td>
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        </tr>
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      </table>
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</div>
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<div class="memdoc">
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<p>
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Constructor. 
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<p>
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</div>
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</div><p>
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<a class="anchor" name="2715233827c346ab15504dc75d6e9714"></a><!-- doxytag: member="QwtPlotRasterItem::~QwtPlotRasterItem" ref="2715233827c346ab15504dc75d6e9714" args="()" -->
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<div class="memitem">
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<div class="memproto">
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      <table class="memname">
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        <tr>
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          <td class="memname">QwtPlotRasterItem::~QwtPlotRasterItem           </td>
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          <td>(</td>
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          <td class="paramname">          </td>
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          <td>&nbsp;)&nbsp;</td>
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          <td><code> [virtual]</code></td>
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        </tr>
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      </table>
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</div>
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<div class="memdoc">
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<p>
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Destructor. 
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<p>
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</div>
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</div><p>
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<hr><h2>Member Function Documentation</h2>
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<a class="anchor" name="96b2faa0bc0fe086bff1abe72bcb2016"></a><!-- doxytag: member="QwtPlotRasterItem::alpha" ref="96b2faa0bc0fe086bff1abe72bcb2016" args="() const " -->
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<div class="memitem">
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<div class="memproto">
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      <table class="memname">
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        <tr>
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          <td class="memname">int QwtPlotRasterItem::alpha           </td>
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          <td>(</td>
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          <td class="paramname">          </td>
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          <td>&nbsp;)&nbsp;</td>
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          <td> const</td>
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        </tr>
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      </table>
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</div>
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<div class="memdoc">
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<p>
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<dl class="return" compact><dt><b>Returns:</b></dt><dd>Alpha value of the raster item </dd></dl>
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<dl class="see" compact><dt><b>See also:</b></dt><dd><a class="el" href="class_qwt_plot_raster_item.html#14f2ab8ec0994384e6269f869c352273" title="Set an alpha value for the raster data.">setAlpha()</a> </dd></dl>
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</div>
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</div><p>
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<a class="anchor" name="c953db5d88084f416b4dbc3ca8a323f3"></a><!-- doxytag: member="QwtPlotRasterItem::cachePolicy" ref="c953db5d88084f416b4dbc3ca8a323f3" args="() const " -->
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<div class="memitem">
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<div class="memproto">
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      <table class="memname">
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        <tr>
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          <td class="memname"><a class="el" href="class_qwt_plot_raster_item.html#94929fc4c31c3dab75ee5adcac2d57b0">QwtPlotRasterItem::CachePolicy</a> QwtPlotRasterItem::cachePolicy           </td>
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          <td>(</td>
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          <td class="paramname">          </td>
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          <td>&nbsp;)&nbsp;</td>
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          <td> const</td>
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        </tr>
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      </table>
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</div>
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<div class="memdoc">
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<p>
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<dl class="return" compact><dt><b>Returns:</b></dt><dd>Cache policy </dd></dl>
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<dl class="see" compact><dt><b>See also:</b></dt><dd><a class="el" href="class_qwt_plot_raster_item.html#94929fc4c31c3dab75ee5adcac2d57b0">CachePolicy</a>, <a class="el" href="class_qwt_plot_raster_item.html#31f74199f7e333c2683b0f18289e4c7f">setCachePolicy()</a> </dd></dl>
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</div>
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</div><p>
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<a class="anchor" name="81b062af415a8df33262f23768fd71ad"></a><!-- doxytag: member="QwtPlotRasterItem::draw" ref="81b062af415a8df33262f23768fd71ad" args="(QPainter *p, const QwtScaleMap &amp;xMap, const QwtScaleMap &amp;yMap, const QRect &amp;rect) const " -->
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<div class="memitem">
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<div class="memproto">
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      <table class="memname">
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        <tr>
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          <td class="memname">void QwtPlotRasterItem::draw           </td>
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          <td>(</td>
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          <td class="paramtype">QPainter *&nbsp;</td>
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          <td class="paramname"> <em>painter</em>, </td>
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        </tr>
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        <tr>
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          <td class="paramkey"></td>
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          <td></td>
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          <td class="paramtype">const <a class="el" href="class_qwt_scale_map.html">QwtScaleMap</a> &amp;&nbsp;</td>
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          <td class="paramname"> <em>xMap</em>, </td>
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        </tr>
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        <tr>
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          <td class="paramkey"></td>
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          <td></td>
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          <td class="paramtype">const <a class="el" href="class_qwt_scale_map.html">QwtScaleMap</a> &amp;&nbsp;</td>
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          <td class="paramname"> <em>yMap</em>, </td>
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        </tr>
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        <tr>
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          <td class="paramkey"></td>
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          <td></td>
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          <td class="paramtype">const QRect &amp;&nbsp;</td>
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          <td class="paramname"> <em>canvasRect</em></td><td>&nbsp;</td>
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        </tr>
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        <tr>
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          <td></td>
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          <td>)</td>
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          <td></td><td></td><td> const<code> [virtual]</code></td>
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        </tr>
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      </table>
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</div>
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<div class="memdoc">
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<p>
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Draw the raster data. 
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<p>
256
 
<dl compact><dt><b>Parameters:</b></dt><dd>
257
 
  <table border="0" cellspacing="2" cellpadding="0">
258
 
    <tr><td valign="top"></td><td valign="top"><em>painter</em>&nbsp;</td><td>Painter </td></tr>
259
 
    <tr><td valign="top"></td><td valign="top"><em>xMap</em>&nbsp;</td><td>X-Scale Map </td></tr>
260
 
    <tr><td valign="top"></td><td valign="top"><em>yMap</em>&nbsp;</td><td>Y-Scale Map </td></tr>
261
 
    <tr><td valign="top"></td><td valign="top"><em>canvasRect</em>&nbsp;</td><td>Contents rect of the plot canvas </td></tr>
262
 
  </table>
263
 
</dl>
264
 
 
265
 
<p>Implements <a class="el" href="class_qwt_plot_item.html#5483623e4fd1ae85b06b93523784358b">QwtPlotItem</a>.</p>
266
 
 
267
 
<p>Reimplemented in <a class="el" href="class_qwt_plot_spectrogram.html#b76245f919a08375b1f975d507e2afea">QwtPlotSpectrogram</a>.</p>
268
 
 
269
 
</div>
270
 
</div><p>
271
 
<a class="anchor" name="547ce4d8d031b230226cfbd509ef65b5"></a><!-- doxytag: member="QwtPlotRasterItem::invalidateCache" ref="547ce4d8d031b230226cfbd509ef65b5" args="()" -->
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<div class="memitem">
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<div class="memproto">
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      <table class="memname">
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        <tr>
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          <td class="memname">void QwtPlotRasterItem::invalidateCache           </td>
277
 
          <td>(</td>
278
 
          <td class="paramname">          </td>
279
 
          <td>&nbsp;)&nbsp;</td>
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          <td></td>
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        </tr>
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      </table>
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</div>
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<div class="memdoc">
285
 
 
286
 
<p>
287
 
Invalidate the paint cache <dl class="see" compact><dt><b>See also:</b></dt><dd><a class="el" href="class_qwt_plot_raster_item.html#31f74199f7e333c2683b0f18289e4c7f">setCachePolicy()</a> </dd></dl>
288
 
 
289
 
</div>
290
 
</div><p>
291
 
<a class="anchor" name="610342c1ff21beed110f6454b705368c"></a><!-- doxytag: member="QwtPlotRasterItem::rasterHint" ref="610342c1ff21beed110f6454b705368c" args="(const QwtDoubleRect &amp;) const " -->
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<div class="memitem">
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<div class="memproto">
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      <table class="memname">
295
 
        <tr>
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          <td class="memname">QSize QwtPlotRasterItem::rasterHint           </td>
297
 
          <td>(</td>
298
 
          <td class="paramtype">const QwtDoubleRect &amp;&nbsp;</td>
299
 
          <td class="paramname">          </td>
300
 
          <td>&nbsp;)&nbsp;</td>
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          <td> const<code> [virtual]</code></td>
302
 
        </tr>
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      </table>
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</div>
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<div class="memdoc">
306
 
 
307
 
<p>
308
 
Returns the recommended raster for a given rect. 
309
 
<p>
310
 
F.e the raster hint can be used to limit the resolution of the image that is rendered.<p>
311
 
The default implementation returns an invalid size (QSize()), what means: no hint. 
312
 
<p>Reimplemented in <a class="el" href="class_qwt_plot_spectrogram.html#4e59ddce72db5df3d0be3986e74ab1f7">QwtPlotSpectrogram</a>.</p>
313
 
 
314
 
</div>
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</div><p>
316
 
<a class="anchor" name="8767aea6b99f44109e8490e8ee2c3cbe"></a><!-- doxytag: member="QwtPlotRasterItem::renderImage" ref="8767aea6b99f44109e8490e8ee2c3cbe" args="(const QwtScaleMap &amp;xMap, const QwtScaleMap &amp;yMap, const QwtDoubleRect &amp;area) const =0" -->
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<div class="memitem">
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<div class="memproto">
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      <table class="memname">
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        <tr>
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          <td class="memname">virtual QImage QwtPlotRasterItem::renderImage           </td>
322
 
          <td>(</td>
323
 
          <td class="paramtype">const <a class="el" href="class_qwt_scale_map.html">QwtScaleMap</a> &amp;&nbsp;</td>
324
 
          <td class="paramname"> <em>xMap</em>, </td>
325
 
        </tr>
326
 
        <tr>
327
 
          <td class="paramkey"></td>
328
 
          <td></td>
329
 
          <td class="paramtype">const <a class="el" href="class_qwt_scale_map.html">QwtScaleMap</a> &amp;&nbsp;</td>
330
 
          <td class="paramname"> <em>yMap</em>, </td>
331
 
        </tr>
332
 
        <tr>
333
 
          <td class="paramkey"></td>
334
 
          <td></td>
335
 
          <td class="paramtype">const QwtDoubleRect &amp;&nbsp;</td>
336
 
          <td class="paramname"> <em>area</em></td><td>&nbsp;</td>
337
 
        </tr>
338
 
        <tr>
339
 
          <td></td>
340
 
          <td>)</td>
341
 
          <td></td><td></td><td> const<code> [protected, pure virtual]</code></td>
342
 
        </tr>
343
 
      </table>
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</div>
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<div class="memdoc">
346
 
 
347
 
<p>
348
 
Renders an image for an area<p>
349
 
The format of the image must be QImage::Format_Indexed8, QImage::Format_RGB32 or QImage::Format_ARGB32<p>
350
 
<dl compact><dt><b>Parameters:</b></dt><dd>
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  <table border="0" cellspacing="2" cellpadding="0">
352
 
    <tr><td valign="top"></td><td valign="top"><em>xMap</em>&nbsp;</td><td>Maps x-values into pixel coordinates. </td></tr>
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    <tr><td valign="top"></td><td valign="top"><em>yMap</em>&nbsp;</td><td>Maps y-values into pixel coordinates. </td></tr>
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    <tr><td valign="top"></td><td valign="top"><em>area</em>&nbsp;</td><td>Requested area for the image in scale coordinates </td></tr>
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  </table>
356
 
</dl>
357
 
 
358
 
<p>Implemented in <a class="el" href="class_qwt_plot_spectrogram.html#698a7039b51fa259c39bd93a64743eea">QwtPlotSpectrogram</a>.</p>
359
 
 
360
 
</div>
361
 
</div><p>
362
 
<a class="anchor" name="14f2ab8ec0994384e6269f869c352273"></a><!-- doxytag: member="QwtPlotRasterItem::setAlpha" ref="14f2ab8ec0994384e6269f869c352273" args="(int alpha)" -->
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<div class="memitem">
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<div class="memproto">
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      <table class="memname">
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        <tr>
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          <td class="memname">void QwtPlotRasterItem::setAlpha           </td>
368
 
          <td>(</td>
369
 
          <td class="paramtype">int&nbsp;</td>
370
 
          <td class="paramname"> <em>alpha</em>          </td>
371
 
          <td>&nbsp;)&nbsp;</td>
372
 
          <td></td>
373
 
        </tr>
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      </table>
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</div>
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<div class="memdoc">
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378
 
<p>
379
 
Set an alpha value for the raster data. 
380
 
<p>
381
 
Often a plot has several types of raster data organized in layers. ( f.e a geographical map, with weather statistics ). Using <a class="el" href="class_qwt_plot_raster_item.html#14f2ab8ec0994384e6269f869c352273" title="Set an alpha value for the raster data.">setAlpha()</a> raster items can be stacked easily.<p>
382
 
The alpha value is a value [0, 255] to control the transparency of the image. 0 represents a fully transparent color, while 255 represents a fully opaque color.<p>
383
 
<dl compact><dt><b>Parameters:</b></dt><dd>
384
 
  <table border="0" cellspacing="2" cellpadding="0">
385
 
    <tr><td valign="top"></td><td valign="top"><em>alpha</em>&nbsp;</td><td>Alpha value</td></tr>
386
 
  </table>
387
 
</dl>
388
 
<ul>
389
 
<li>alpha &gt;= 0<br>
390
 
 All alpha values of the pixels returned by <a class="el" href="class_qwt_plot_raster_item.html#8767aea6b99f44109e8490e8ee2c3cbe">renderImage()</a> will be set to alpha, beside those with an alpha value of 0 (invalid pixels).</li><li>alpha &lt; 0 The alpha values returned by <a class="el" href="class_qwt_plot_raster_item.html#8767aea6b99f44109e8490e8ee2c3cbe">renderImage()</a> are not changed.</li></ul>
391
 
<p>
392
 
The default alpha value is -1.<p>
393
 
<dl class="see" compact><dt><b>See also:</b></dt><dd><a class="el" href="class_qwt_plot_raster_item.html#96b2faa0bc0fe086bff1abe72bcb2016">alpha()</a> </dd></dl>
394
 
 
395
 
</div>
396
 
</div><p>
397
 
<a class="anchor" name="31f74199f7e333c2683b0f18289e4c7f"></a><!-- doxytag: member="QwtPlotRasterItem::setCachePolicy" ref="31f74199f7e333c2683b0f18289e4c7f" args="(CachePolicy)" -->
398
 
<div class="memitem">
399
 
<div class="memproto">
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      <table class="memname">
401
 
        <tr>
402
 
          <td class="memname">void QwtPlotRasterItem::setCachePolicy           </td>
403
 
          <td>(</td>
404
 
          <td class="paramtype"><a class="el" href="class_qwt_plot_raster_item.html#94929fc4c31c3dab75ee5adcac2d57b0">QwtPlotRasterItem::CachePolicy</a>&nbsp;</td>
405
 
          <td class="paramname"> <em>policy</em>          </td>
406
 
          <td>&nbsp;)&nbsp;</td>
407
 
          <td></td>
408
 
        </tr>
409
 
      </table>
410
 
</div>
411
 
<div class="memdoc">
412
 
 
413
 
<p>
414
 
Change the cache policy<p>
415
 
The default policy is NoCache<p>
416
 
<dl compact><dt><b>Parameters:</b></dt><dd>
417
 
  <table border="0" cellspacing="2" cellpadding="0">
418
 
    <tr><td valign="top"></td><td valign="top"><em>policy</em>&nbsp;</td><td>Cache policy </td></tr>
419
 
  </table>
420
 
</dl>
421
 
<dl class="see" compact><dt><b>See also:</b></dt><dd><a class="el" href="class_qwt_plot_raster_item.html#94929fc4c31c3dab75ee5adcac2d57b0">CachePolicy</a>, <a class="el" href="class_qwt_plot_raster_item.html#c953db5d88084f416b4dbc3ca8a323f3">cachePolicy()</a> </dd></dl>
422
 
 
423
 
</div>
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</div><p>
425
 
</div>
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<hr size="1"><address style="text-align: right;"><small>Generated on Sun Mar 22 16:41:25 2009 for Qwt User's Guide by&nbsp;
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<a href="http://www.doxygen.org/index.html">
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<img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.5.8 </small></address>
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</body>
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