176 lines
7.8 KiB
XML
176 lines
7.8 KiB
XML
|
<?xml version="1.0" encoding="UTF-8"?>
|
||
|
|
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
|
||
|
|
"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
|
||
|
|
<refentry id="glPixelZoom">
|
||
|
|
<refmeta>
|
||
|
|
<refmetainfo>
|
||
|
|
<copyright>
|
||
|
|
<year>1991-2006</year>
|
||
|
|
<holder>Silicon Graphics, Inc.</holder>
|
||
|
|
</copyright>
|
||
|
|
</refmetainfo>
|
||
|
|
<refentrytitle>glPixelZoom</refentrytitle>
|
||
|
|
<manvolnum>3G</manvolnum>
|
||
|
|
</refmeta>
|
||
|
|
<refnamediv>
|
||
|
|
<refname>glPixelZoom</refname>
|
||
|
|
<refpurpose>specify the pixel zoom factors</refpurpose>
|
||
|
|
</refnamediv>
|
||
|
|
<refsynopsisdiv><title>C Specification</title>
|
||
|
|
<funcsynopsis>
|
||
|
|
<funcprototype>
|
||
|
|
<funcdef>void <function>glPixelZoom</function></funcdef>
|
||
|
|
<paramdef>GLfloat <parameter>xfactor</parameter></paramdef>
|
||
|
|
<paramdef>GLfloat <parameter>yfactor</parameter></paramdef>
|
||
|
|
</funcprototype>
|
||
|
|
</funcsynopsis>
|
||
|
|
</refsynopsisdiv>
|
||
|
|
<!-- eqn: ignoring delim $$ -->
|
||
|
|
<refsect1 id="parameters"><title>Parameters</title>
|
||
|
|
<variablelist>
|
||
|
|
<varlistentry>
|
||
|
|
<term><parameter>xfactor</parameter></term>
|
||
|
|
<term><parameter>yfactor</parameter></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specify the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">x</mml:mi></mml:math></inlineequation>
|
||
|
|
and
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">y</mml:mi></mml:math></inlineequation>
|
||
|
|
zoom factors for pixel write operations.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
</variablelist>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="description"><title>Description</title>
|
||
|
|
<para>
|
||
|
|
<function>glPixelZoom</function> specifies values for the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">x</mml:mi></mml:math></inlineequation>
|
||
|
|
and
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">y</mml:mi></mml:math></inlineequation>
|
||
|
|
zoom factors.
|
||
|
|
During the execution of <citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry> or <citerefentry><refentrytitle>glCopyPixels</refentrytitle></citerefentry>,
|
||
|
|
if
|
||
|
|
(<inlineequation><mml:math>
|
||
|
|
<!-- eqn: xr:-->
|
||
|
|
<mml:mi mathvariant="italic">xr</mml:mi>
|
||
|
|
</mml:math></inlineequation>,
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: yr:-->
|
||
|
|
<mml:mi mathvariant="italic">yr</mml:mi>
|
||
|
|
</mml:math></inlineequation>)
|
||
|
|
is the current raster position,
|
||
|
|
and a given element is in the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">m</mml:mi></mml:math></inlineequation>th
|
||
|
|
row and
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>th
|
||
|
|
column of the pixel rectangle,
|
||
|
|
then pixels whose centers are in the rectangle with corners at
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
(<inlineequation><mml:math>
|
||
|
|
<!-- eqn: xr + n cdot xfactor:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">xr</mml:mi>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">n</mml:mi>
|
||
|
|
<mml:mo>·</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">xfactor</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>,
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: yr + m cdot yfactor:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">yr</mml:mi>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">m</mml:mi>
|
||
|
|
<mml:mo>·</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">yfactor</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>)
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
(<inlineequation><mml:math>
|
||
|
|
<!-- eqn: xr + (n+1) cdot xfactor:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">xr</mml:mi>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">n</mml:mi>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
<mml:mo>·</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">xfactor</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>,
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: yr + (m+1) cdot yfactor:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">yr</mml:mi>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">m</mml:mi>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
<mml:mo>·</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">yfactor</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>)
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
are candidates for replacement.
|
||
|
|
Any pixel whose center lies on the bottom or left edge of this rectangular
|
||
|
|
region is also modified.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
Pixel zoom factors are not limited to positive values.
|
||
|
|
Negative zoom factors reflect the resulting image about the current
|
||
|
|
raster position.
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="errors"><title>Errors</title>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_OPERATION</constant> is generated if <function>glPixelZoom</function>
|
||
|
|
is executed between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>
|
||
|
|
and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="associatedgets"><title>Associated Gets</title>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_ZOOM_X</constant>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_ZOOM_Y</constant>
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="seealso"><title>See Also</title>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glCopyPixels</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry>
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="Copyright"><title>Copyright</title>
|
||
|
|
<para>
|
||
|
|
Copyright <trademark class="copyright"></trademark> 1991-2006
|
||
|
|
Silicon Graphics, Inc. This document is licensed under the SGI
|
||
|
|
Free Software B License. For details, see
|
||
|
|
<ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
</refentry>
|