upstream-man-pages/man2/xhtml/glPixelZoom.xml

   1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd">
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   3 <?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>glPixelZoom</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glPixelZoom"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glPixelZoom — specify the pixel zoom factors</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glPixelZoom</b>(</code></td><td>GLfloat  </td><td><var class="pdparam">xfactor</var>, </td></tr><tr><td> </td><td>GLfloat  </td><td><var class="pdparam">yfactor</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>xfactor</code></em>, </span><span class="term"><em class="parameter"><code>yfactor</code></em></span></dt><dd><p>
   4                     Specify the
   5                     <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">x</mml:mi></mml:math>
   6                     and
   7                     <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">y</mml:mi></mml:math>
   8                     zoom factors for pixel write operations.
   9                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  10             <code class="function">glPixelZoom</code> specifies values for the
  11             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">x</mml:mi></mml:math>
  12             and
  13             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">y</mml:mi></mml:math>
  14             zoom factors.
  15             During the execution of <a class="citerefentry" href="glDrawPixels.xml"><span class="citerefentry"><span class="refentrytitle">glDrawPixels</span></span></a> or <a class="citerefentry" href="glCopyPixels.xml"><span class="citerefentry"><span class="refentrytitle">glCopyPixels</span></span></a>,
  16             if
  17             (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  18
  19                 <mml:mi mathvariant="italic">xr</mml:mi>
  20             </mml:math>,
  21             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  22
  23                 <mml:mi mathvariant="italic">yr</mml:mi>
  24             </mml:math>)
  25             is the current raster position,
  26             and a given element is in the
  27             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">m</mml:mi></mml:math>th
  28             row and
  29             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">n</mml:mi></mml:math>th
  30             column of the pixel rectangle,
  31             then pixels whose centers are in the rectangle with corners at
  32         </p><p>
  33             (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  34
  35                 <mml:mrow>
  36                     <mml:mi mathvariant="italic">xr</mml:mi>
  37                     <mml:mo>+</mml:mo>
  38                     <mml:mrow>
  39                         <mml:mi mathvariant="italic">n</mml:mi>
  40                         <mml:mo>·</mml:mo>
  41                         <mml:mi mathvariant="italic">xfactor</mml:mi>
  42                     </mml:mrow>
  43                 </mml:mrow>
  44             </mml:math>,
  45             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  46
  47                 <mml:mrow>
  48                     <mml:mi mathvariant="italic">yr</mml:mi>
  49                     <mml:mo>+</mml:mo>
  50                     <mml:mrow>
  51                         <mml:mi mathvariant="italic">m</mml:mi>
  52                         <mml:mo>·</mml:mo>
  53                         <mml:mi mathvariant="italic">yfactor</mml:mi>
  54                     </mml:mrow>
  55                 </mml:mrow>
  56             </mml:math>)
  57         </p><p>
  58             (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  59
  60                 <mml:mrow>
  61                     <mml:mi mathvariant="italic">xr</mml:mi>
  62                     <mml:mo>+</mml:mo>
  63                     <mml:mrow>
  64                         <mml:mfenced open="(" close=")">
  65                             <mml:mrow>
  66                                 <mml:mi mathvariant="italic">n</mml:mi>
  67                                 <mml:mo>+</mml:mo>
  68                                 <mml:mn>1</mml:mn>
  69                             </mml:mrow>
  70                         </mml:mfenced>
  71                         <mml:mo>·</mml:mo>
  72                         <mml:mi mathvariant="italic">xfactor</mml:mi>
  73                     </mml:mrow>
  74                 </mml:mrow>
  75             </mml:math>,
  76             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  77
  78                 <mml:mrow>
  79                     <mml:mi mathvariant="italic">yr</mml:mi>
  80                     <mml:mo>+</mml:mo>
  81                     <mml:mrow>
  82                         <mml:mfenced open="(" close=")">
  83                             <mml:mrow>
  84                                 <mml:mi mathvariant="italic">m</mml:mi>
  85                                 <mml:mo>+</mml:mo>
  86                                 <mml:mn>1</mml:mn>
  87                             </mml:mrow>
  88                         </mml:mfenced>
  89                         <mml:mo>·</mml:mo>
  90                         <mml:mi mathvariant="italic">yfactor</mml:mi>
  91                     </mml:mrow>
  92                 </mml:mrow>
  93             </mml:math>)
  94         </p><p>
  95             are candidates for replacement.
  96             Any pixel whose center lies on the bottom or left edge of this rectangular
  97             region is also modified.
  98         </p><p>
  99             Pixel zoom factors are not limited to positive values.
 100             Negative zoom factors reflect the resulting image about the current
 101             raster position.
 102         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
 103             <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glPixelZoom</code>
 104             is executed between the execution of <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a>
 105             and the corresponding execution of <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.
 106         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
 107             <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_ZOOM_X</code>
 108         </p><p>
 109             <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_ZOOM_Y</code>
 110         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 111             <a class="citerefentry" href="glCopyPixels.xml"><span class="citerefentry"><span class="refentrytitle">glCopyPixels</span></span></a>,
 112             <a class="citerefentry" href="glDrawPixels.xml"><span class="citerefentry"><span class="refentrytitle">glDrawPixels</span></span></a>
 113         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 114             Copyright <span class="trademark"></span>© 1991-2006
 115             Silicon Graphics, Inc. This document is licensed under the SGI
 116             Free Software B License. For details, see
 117             <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
 118         </p></div></div></body></html>