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<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
<refentry id="libgimpmath-GimpMath">
<refmeta>
<refentrytitle role="top_of_page" id="libgimpmath-GimpMath.top_of_page">GimpMath</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo>LIBGIMPMATH Library</refmiscinfo>
</refmeta>
<refnamediv>
<refname>GimpMath</refname>
<refpurpose>Mathematical definitions and macros.</refpurpose>
<!--[<xref linkend="desc" endterm="desc.title"/>]-->
</refnamediv>
<refsynopsisdiv id="libgimpmath-GimpMath.synopsis" role="synopsis">
<title role="synopsis.title">Synopsis</title>
<synopsis>
#define <link linkend="RINT:CAPS">RINT</link> (x)
#define <link linkend="ROUND:CAPS">ROUND</link> (x)
#define <link linkend="SQR:CAPS">SQR</link> (x)
#define <link linkend="MAX255:CAPS">MAX255</link> (a)
#define <link linkend="CLAMP0255:CAPS">CLAMP0255</link> (a)
#define <link linkend="gimp-deg-to-rad">gimp_deg_to_rad</link> (angle)
#define <link linkend="gimp-rad-to-deg">gimp_rad_to_deg</link> (angle)
</synopsis>
</refsynopsisdiv>
<refsect1 id="libgimpmath-GimpMath.description" role="desc">
<title role="desc.title">Description</title>
<para>
Mathematical definitions and macros. These macros should be used
rather than the ones from math.h for enhanced portability.
</para>
</refsect1>
<refsect1 id="libgimpmath-GimpMath.details" role="details">
<title role="details.title">Details</title>
<refsect2 id="RINT:CAPS" role="macro">
<title>RINT()</title>
<indexterm zone="RINT:CAPS"><primary>RINT</primary></indexterm><programlisting>#define RINT(x)</programlisting>
<para>
This macro rounds its argument <parameter>x</parameter> to an integer value in floating point
format.
</para><variablelist role="params">
<varlistentry><term><parameter>x</parameter> :</term>
<listitem><simpara>the value to be rounded.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="ROUND:CAPS" role="macro">
<title>ROUND()</title>
<indexterm zone="ROUND:CAPS"><primary>ROUND</primary></indexterm><programlisting>#define ROUND(x) ((int) ((x) + 0.5))
</programlisting>
<para>
This macro rounds its argument <parameter>x</parameter> to the nearest integer.
</para><variablelist role="params">
<varlistentry><term><parameter>x</parameter> :</term>
<listitem><simpara>the value to be rounded.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="SQR:CAPS" role="macro">
<title>SQR()</title>
<indexterm zone="SQR:CAPS"><primary>SQR</primary></indexterm><programlisting>#define SQR(x) ((x) * (x))
</programlisting>
<para>
This macro squares its argument <parameter>x</parameter>.
</para><variablelist role="params">
<varlistentry><term><parameter>x</parameter> :</term>
<listitem><simpara>the value to be squared.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="MAX255:CAPS" role="macro">
<title>MAX255()</title>
<indexterm zone="MAX255:CAPS"><primary>MAX255</primary></indexterm><programlisting>#define MAX255(a) ((a) | (((a) & 256) - (((a) & 256) >> 8)))
</programlisting>
<para>
This macro limits it argument <parameter>a</parameter>, an (0-511) int, to 255.
</para><variablelist role="params">
<varlistentry><term><parameter>a</parameter> :</term>
<listitem><simpara>the value to be limited.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="CLAMP0255:CAPS" role="macro">
<title>CLAMP0255()</title>
<indexterm zone="CLAMP0255:CAPS"><primary>CLAMP0255</primary></indexterm><programlisting>#define CLAMP0255(a) CLAMP(a,0,255)
</programlisting>
<para>
This macro clamps its argument <parameter>a</parameter>, an int32-range int, between 0 and
255 inclusive.
</para><variablelist role="params">
<varlistentry><term><parameter>a</parameter> :</term>
<listitem><simpara>the value to be clamped.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="gimp-deg-to-rad" role="macro">
<title>gimp_deg_to_rad()</title>
<indexterm zone="gimp-deg-to-rad"><primary>gimp_deg_to_rad</primary></indexterm><programlisting>#define gimp_deg_to_rad(angle) ((angle) * (2.0 * G_PI) / 360.0)
</programlisting>
<para>
This macro converts its argument <parameter>angle</parameter> from degree to radian.
</para><variablelist role="params">
<varlistentry><term><parameter>angle</parameter> :</term>
<listitem><simpara>the angle to be converted.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
<refsect2 id="gimp-rad-to-deg" role="macro">
<title>gimp_rad_to_deg()</title>
<indexterm zone="gimp-rad-to-deg"><primary>gimp_rad_to_deg</primary></indexterm><programlisting>#define gimp_rad_to_deg(angle) ((angle) * 360.0 / (2.0 * G_PI))
</programlisting>
<para>
This macro converts its argument <parameter>angle</parameter> from radian to degree.
</para><variablelist role="params">
<varlistentry><term><parameter>angle</parameter> :</term>
<listitem><simpara>the angle to be converted.
</simpara></listitem></varlistentry>
</variablelist></refsect2>
</refsect1>
</refentry>
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