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1 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd"> |
2 | <!-- saved from url=(0013)about:internet --> | |
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> |