<?xml version="1.0" encoding="UTF-8"?>
<!--
 * Scilab ( https://www.scilab.org/ ) - This file is part of Scilab
 * Copyright (C) ENPC - Jean-Philippe Chancelier
 *
 * Copyright (C) 2012 - 2016 - Scilab Enterprises
 *
 * This file is hereby licensed under the terms of the GNU GPL v2.0,
 * pursuant to article 5.3.4 of the CeCILL v.2.1.
 * This file was originally licensed under the terms of the CeCILL v2.1,
 * and continues to be available under such terms.
 * For more information, see the COPYING file which you should have received
 * along with this program.
 *
 -->
<refentry xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:svg="http://www.w3.org/2000/svg" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:db="http://docbook.org/ns/docbook" xmlns:scilab="http://www.scilab.org"  xml:lang="en" xml:id="grayplot">
    <refnamediv>
        <refname>grayplot</refname>
        <refpurpose>2D plot of a surface using
            colors
        </refpurpose>
    </refnamediv>
    <refsynopsisdiv>
        <title>Syntax</title>
        <synopsis>grayplot(x,y,z,[strf,rect,nax])
            grayplot(x,y,z,&lt;opt_args&gt;)
        </synopsis>
    </refsynopsisdiv>
    <refsection>
        <title>Arguments</title>
        <variablelist>
            <varlistentry>
                <term>x,y</term>
                <listitem>
                    <para>real row vectors of size n1 and n2.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term>z</term>
                <listitem>
                    <para>
                        real matrix of size (n1,n2). <literal>z(i,j)</literal> is the value
                        of the surface at the point (x(i),y(j)).
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term>&lt;opt_args&gt;</term>
                <listitem>
                    <para>
                        This represents a sequence of statements <literal>key1=value1,
                            key2=value2
                        </literal>
                        ,... where <literal>key1</literal>,
                        <literal>key2,...</literal> can be one of the following: rect, nax, strf, logflag
                        or axesflag and frameflag (see <literal>plot2d</literal>).
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term>strf,rect,nax</term>
                <listitem>
                    <para>
                        see <literal>plot2d</literal>.
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
    </refsection>
    <refsection>
        <title>Description</title>
        <para>
            <literal>grayplot</literal> makes a 2D plot of the surface given by
            <literal>z</literal> on a grid defined by <literal>x</literal> and <literal>y</literal>.
            Each rectangle on the grid is filled with a gray or color level depending
            on the average value of <literal>z</literal> on the corners of the
            rectangle. If z contains %nan values, the surrounding rectangles are not displayed.
        </para>
        <para>
            Enter the command <literal>grayplot()</literal> to see a demo.
        </para>
    </refsection>
    <refsection>
        <title>Examples</title>
        <programlisting role="example"><![CDATA[
x=-10:10;
y=-10:10;
m=rand(21,21);
grayplot(x,y,m,rect=[-20,-20,20,20])
 ]]></programlisting>
        <scilab:image>
            x=-10:10;
            y=-10:10;
            m=rand(21,21);
            grayplot(x,y,m,rect=[-20,-20,20,20])
        </scilab:image>
        <programlisting role="example"><![CDATA[
t=-%pi:0.1:%pi;
m=sin(t)'*cos(t);
clf()
grayplot(t,t,m)
 ]]></programlisting>
        <scilab:image>
            t=-%pi:0.1:%pi;
            m=sin(t)'*cos(t);
            clf()
            grayplot(t,t,m)

        </scilab:image>
    </refsection>
    <refsection role="see also">
        <title>See also</title>
        <simplelist type="inline">
            <member>
                <link linkend="fgrayplot">fgrayplot</link>
            </member>
            <member>
                <link linkend="plot2d">plot2d</link>
            </member>
            <member>
                <link linkend="Sgrayplot">Sgrayplot</link>
            </member>
            <member>
                <link linkend="Sfgrayplot">Sfgrayplot</link>
            </member>
        </simplelist>
    </refsection>
    <refsection>
        <title>History</title>
        <revhistory>
            <revision>
                <revnumber>5.5.0</revnumber>
                <revremark>
                    Option <function>logflag</function> introduced.
                </revremark>
            </revision>
        </revhistory>
    </refsection>
</refentry>
