<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- Created by GNU Texinfo 6.5, http://www.gnu.org/software/texinfo/ -->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Graphics Objects (GNU Octave (version 5.1.0))</title>
<meta name="description" content="Graphics Objects (GNU Octave (version 5.1.0))">
<meta name="keywords" content="Graphics Objects (GNU Octave (version 5.1.0))">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="makeinfo">
<link href="index.html#Top" rel="start" title="Top">
<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index">
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
<link href="Graphics-Data-Structures.html#Graphics-Data-Structures" rel="up" title="Graphics Data Structures">
<link href="Graphics-Object-Properties.html#Graphics-Object-Properties" rel="next" title="Graphics Object Properties">
<link href="Introduction-to-Graphics-Structures.html#Introduction-to-Graphics-Structures" rel="prev" title="Introduction to Graphics Structures">
<style type="text/css">
<!--
a.summary-letter {text-decoration: none}
blockquote.indentedblock {margin-right: 0em}
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
blockquote.smallquotation {font-size: smaller}
div.display {margin-left: 3.2em}
div.example {margin-left: 3.2em}
div.lisp {margin-left: 3.2em}
div.smalldisplay {margin-left: 3.2em}
div.smallexample {margin-left: 3.2em}
div.smalllisp {margin-left: 3.2em}
kbd {font-style: oblique}
pre.display {font-family: inherit}
pre.format {font-family: inherit}
pre.menu-comment {font-family: serif}
pre.menu-preformatted {font-family: serif}
pre.smalldisplay {font-family: inherit; font-size: smaller}
pre.smallexample {font-size: smaller}
pre.smallformat {font-family: inherit; font-size: smaller}
pre.smalllisp {font-size: smaller}
span.nolinebreak {white-space: nowrap}
span.roman {font-family: initial; font-weight: normal}
span.sansserif {font-family: sans-serif; font-weight: normal}
ul.no-bullet {list-style: none}
-->
</style>
<link rel="stylesheet" type="text/css" href="octave.css">
</head>
<body lang="en">
<a name="Graphics-Objects"></a>
<div class="header">
<p>
Next: <a href="Graphics-Object-Properties.html#Graphics-Object-Properties" accesskey="n" rel="next">Graphics Object Properties</a>, Previous: <a href="Introduction-to-Graphics-Structures.html#Introduction-to-Graphics-Structures" accesskey="p" rel="prev">Introduction to Graphics Structures</a>, Up: <a href="Graphics-Data-Structures.html#Graphics-Data-Structures" accesskey="u" rel="up">Graphics Data Structures</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<a name="Graphics-Objects-1"></a>
<h4 class="subsection">15.3.2 Graphics Objects</h4>
<a name="index-graphics-objects"></a>
<p>The hierarchy of graphics objects was explained above.
See <a href="Introduction-to-Graphics-Structures.html#Introduction-to-Graphics-Structures">Introduction to Graphics Structures</a>. Here the
specific objects are described, and the properties contained in
these objects are discussed. Keep in mind that
graphics objects are always referenced by <em>handle</em>.
</p>
<dl compact="compact">
<dt>root figure</dt>
<dd><a name="index-root-figure-graphics-object"></a>
<a name="index-graphics-object_002c-root-figure"></a>
<p>The top level of the hierarchy and the parent of all figure objects.
Use <code>groot</code> to obtain the handle of the root graphics object.
</p>
</dd>
<dt>figure</dt>
<dd><a name="index-figure-graphics-object"></a>
<a name="index-graphics-object_002c-figure"></a>
<p>A figure window.
</p>
</dd>
<dt>axes</dt>
<dd><a name="index-axes-graphics-object"></a>
<a name="index-graphics-object_002c-axes"></a>
<p>A set of axes. This object is a child of a figure object and may be a
parent of line, text, image, patch, surface, or light objects.
</p>
</dd>
<dt>line</dt>
<dd><a name="index-line-graphics-object"></a>
<a name="index-graphics-object_002c-line"></a>
<p>A line in two or three dimensions.
</p>
</dd>
<dt>text</dt>
<dd><a name="index-text-graphics-object"></a>
<a name="index-graphics-object_002c-text"></a>
<p>Text annotations.
</p>
</dd>
<dt>image</dt>
<dd><a name="index-image-graphics-object"></a>
<a name="index-graphics-object_002c-image"></a>
<p>A bitmap image.
</p>
</dd>
<dt>patch</dt>
<dd><a name="index-patch-graphics-object"></a>
<a name="index-graphics-object_002c-patch"></a>
<p>A filled polygon, currently limited to two dimensions.
</p>
</dd>
<dt>surface</dt>
<dd><a name="index-surface-graphics-object"></a>
<a name="index-graphics-object_002c-surface"></a>
<p>A three-dimensional surface.
</p>
</dd>
<dt>light</dt>
<dd><a name="index-light-graphics-object"></a>
<a name="index-graphics-object_002c-light"></a>
<p>A light object used for lighting effects on patches and surfaces.
</p></dd>
</dl>
<a name="Creating-Graphics-Objects"></a>
<h4 class="subsubsection">15.3.2.1 Creating Graphics Objects</h4>
<a name="index-creating-graphics-objects"></a>
<p>You can create any graphics object primitive by calling the function of the
same name as the object; In other words, <code>figure</code>, <code>axes</code>,
<code>line</code>, <code>text</code>, <code>image</code>, <code>patch</code>, <code>surface</code>, and
<code>light</code> functions. These fundamental graphic objects automatically become
children of the current axes object as if <code>hold on</code> was in place.
Separately, axes will automatically become children of the current figure
object and figures will become children of the root object.
</p>
<p>If this auto-joining feature is not desired then it is important to call
<code>newplot</code> first to prepare a new figure and axes for plotting.
Alternatively, the easier way is to call a high-level graphics routine which
will both create the plot and then populate it with low-level graphics objects.
Instead of calling <code>line</code>, use <code>plot</code>. Or use <code>surf</code> instead of
<code>surface</code>. Or use <code>fill</code> instead of <code>patch</code>.
</p>
<a name="XREFaxes"></a><dl>
<dt><a name="index-axes"></a><em></em> <strong>axes</strong> <em>()</em></dt>
<dt><a name="index-axes-1"></a><em></em> <strong>axes</strong> <em>(<var>property</var>, <var>value</var>, …)</em></dt>
<dt><a name="index-axes-2"></a><em></em> <strong>axes</strong> <em>(<var>hpar</var>, <var>property</var>, <var>value</var>, …)</em></dt>
<dt><a name="index-axes-3"></a><em></em> <strong>axes</strong> <em>(<var>hax</var>)</em></dt>
<dt><a name="index-axes-4"></a><em><var>h</var> =</em> <strong>axes</strong> <em>(…)</em></dt>
<dd><p>Create a Cartesian axes object and return a handle to it, or set the current
axes to <var>hax</var>.
</p>
<p>Called without any arguments, or with <var>property</var>/<var>value</var> pairs,
construct a new axes. The optional argument <var>hpar</var> is a graphics handle
specifying the parent for the new axes and may be a figure, uipanel, or
uitab.
</p>
<p>Called with a single axes handle argument <var>hax</var>, the function makes
<var>hax</var> the current axes (as returned by <code>gca</code>). It also makes
the figure which contains <var>hax</var> the current figure (as returned by
<code>gcf</code>). Finally, it restacks the parent object’s <code>children</code>
property so that the axes <var>hax</var> appears before all other axes handles
in the list. This causes <var>hax</var> to be displayed on top of any other axes
objects (Z-order stacking). In addition it restacks any legend or colorbar
objects associated with <var>hax</var> so that they are also visible.
</p>
<p>Programming Note: The full list of properties is documented at
<a href="Axes-Properties.html#Axes-Properties">Axes Properties</a>.
</p>
<p><strong>See also:</strong> <a href="#XREFgca">gca</a>, <a href="#XREFset">set</a>, <a href="#XREFget">get</a>.
</p></dd></dl>
<a name="XREFline"></a><dl>
<dt><a name="index-line"></a><em></em> <strong>line</strong> <em>()</em></dt>
<dt><a name="index-line-1"></a><em></em> <strong>line</strong> <em>(<var>x</var>, <var>y</var>)</em></dt>
<dt><a name="index-line-2"></a><em></em> <strong>line</strong> <em>(<var>x</var>, <var>y</var>, <var>z</var>)</em></dt>
<dt><a name="index-line-3"></a><em></em> <strong>line</strong> <em>("xdata", <var>x</var>, "ydata", <var>y</var>)</em></dt>
<dt><a name="index-line-4"></a><em></em> <strong>line</strong> <em>("xdata", <var>x</var>, "ydata", <var>y</var>, "zdata", <var>z</var>)</em></dt>
<dt><a name="index-line-5"></a><em></em> <strong>line</strong> <em>(…, <var>property</var>, <var>value</var>)</em></dt>
<dt><a name="index-line-6"></a><em></em> <strong>line</strong> <em>(<var>hax</var>, …)</em></dt>
<dt><a name="index-line-7"></a><em><var>h</var> =</em> <strong>line</strong> <em>(…)</em></dt>
<dd><p>Create a line object from <var>x</var> and <var>y</var> (and possibly <var>z</var>) and
insert it in the current axes.
</p>
<p>In the standard calling form the data <var>x</var>, <var>y</var>, and <var>z</var> may be
scalars, vectors, or matrices. In the case of matrix inputs, <code>line</code>
will attempt to orient scalars and vectors so the results can be plotted.
This requires that one of the dimensions of the vector match either the
number of rows or the number of columns of the matrix.
</p>
<p>In the low-level calling form (50% higher performance) where the data is
specified by name (<code>line ("xdata", <var>x</var>, …)</code>) the data must be
vectors. If no data is specified (<code>line ()</code>) then
<code><var>x</var> == <var>y</var> = [0, 1]</code><!-- /@w -->.
</p>
<p>Multiple property-value pairs may be specified for the line object, but they
must appear in pairs.
</p>
<p>If called with only <var>property</var>/<var>value</var> pairs then any unspecified
properties use their default values as specified on the root object.
</p>
<p>If the first argument <var>hax</var> is an axes handle, then plot into this axes,
rather than the current axes returned by <code>gca</code>.
</p>
<p>The optional return value <var>h</var> is a graphics handle (or vector of
handles) to the line objects created.
</p>
<p>Programming Note: The full list of properties is documented at
<a href="Line-Properties.html#Line-Properties">Line Properties</a>.
</p>
<p>The function <code>line</code> differs from <code>plot</code> in that line objects are
inserted in to the current axes without first clearing the plot.
</p>
<p><strong>See also:</strong> <a href="Displaying-Images.html#XREFimage">image</a>, <a href="#XREFpatch">patch</a>, <a href="Two_002ddimensional-Geometric-Shapes.html#XREFrectangle">rectangle</a>, <a href="#XREFsurface">surface</a>, <a href="Plot-Annotations.html#XREFtext">text</a>.
</p></dd></dl>
<a name="XREFpatch"></a><dl>
<dt><a name="index-patch"></a><em></em> <strong>patch</strong> <em>()</em></dt>
<dt><a name="index-patch-1"></a><em></em> <strong>patch</strong> <em>(<var>x</var>, <var>y</var>, <var>c</var>)</em></dt>
<dt><a name="index-patch-2"></a><em></em> <strong>patch</strong> <em>(<var>x</var>, <var>y</var>, <var>z</var>, <var>c</var>)</em></dt>
<dt><a name="index-patch-3"></a><em></em> <strong>patch</strong> <em>("Faces", <var>faces</var>, "Vertices", <var>verts</var>, …)</em></dt>
<dt><a name="index-patch-4"></a><em></em> <strong>patch</strong> <em>(…, <var>prop</var>, <var>val</var>, …)</em></dt>
<dt><a name="index-patch-5"></a><em></em> <strong>patch</strong> <em>(…, <var>propstruct</var>, …)</em></dt>
<dt><a name="index-patch-6"></a><em></em> <strong>patch</strong> <em>(<var>hax</var>, …)</em></dt>
<dt><a name="index-patch-7"></a><em><var>h</var> =</em> <strong>patch</strong> <em>(…)</em></dt>
<dd><p>Create patch object in the current axes with vertices at locations
(<var>x</var>, <var>y</var>) and of color <var>c</var>.
</p>
<p>If the vertices are matrices of size MxN then each polygon patch
has M vertices and a total of N polygons will be created. If some polygons
do not have M vertices use NaN to represent "no vertex". If the <var>z</var>
input is present then 3-D patches will be created.
</p>
<p>The color argument <var>c</var> can take many forms. To create polygons
which all share a single color use a string value (e.g., <code>"r"</code> for
red), a scalar value which is scaled by <code>caxis</code> and indexed into the
current colormap, or a 3-element RGB vector with the precise TrueColor.
</p>
<p>If <var>c</var> is a vector of length N then the ith polygon will have a color
determined by scaling entry <var>c</var>(i) according to <code>caxis</code> and then
indexing into the current colormap. More complicated coloring situations
require directly manipulating patch property/value pairs.
</p>
<p>Instead of specifying polygons by matrices <var>x</var> and <var>y</var>, it is
possible to present a unique list of vertices and then a list of polygon
faces created from those vertices. In this case the
<code>"Vertices"</code> matrix will be an Nx2 (2-D patch) or
Nx3 (3-D patch). The MxN <code>"Faces"</code> matrix
describes M polygons having N vertices—each row describes a
single polygon and each column entry is an index into the
<code>"Vertices"</code> matrix to identify a vertex. The patch object
can be created by directly passing the property/value pairs
<code>"Vertices"</code>/<var>verts</var>, <code>"Faces"</code>/<var>faces</var> as
inputs.
</p>
<p>Instead of using property/value pairs, any property can be set by passing a
structure <var>propstruct</var> with the respective field names.
</p>
<p>If the first argument <var>hax</var> is an axes handle, then plot into this axes,
rather than the current axes returned by <code>gca</code>.
</p>
<p>The optional return value <var>h</var> is a graphics handle to the created patch
object.
</p>
<p>Programming Note: The full list of properties is documented at
<a href="Patch-Properties.html#Patch-Properties">Patch Properties</a>. Useful patch properties include:
<code>"cdata"</code>, <code>"edgecolor"</code>, <code>"facecolor"</code>, <code>"faces"</code>,
and <code>"facevertexcdata"</code>.
</p>
<p><strong>See also:</strong> <a href="Two_002dDimensional-Plots.html#XREFfill">fill</a>, <a href="#XREFget">get</a>, <a href="#XREFset">set</a>.
</p></dd></dl>
<a name="XREFsurface"></a><dl>
<dt><a name="index-surface"></a><em></em> <strong>surface</strong> <em>(<var>x</var>, <var>y</var>, <var>z</var>, <var>c</var>)</em></dt>
<dt><a name="index-surface-1"></a><em></em> <strong>surface</strong> <em>(<var>x</var>, <var>y</var>, <var>z</var>)</em></dt>
<dt><a name="index-surface-2"></a><em></em> <strong>surface</strong> <em>(<var>z</var>, <var>c</var>)</em></dt>
<dt><a name="index-surface-3"></a><em></em> <strong>surface</strong> <em>(<var>z</var>)</em></dt>
<dt><a name="index-surface-4"></a><em></em> <strong>surface</strong> <em>(…, <var>prop</var>, <var>val</var>, …)</em></dt>
<dt><a name="index-surface-5"></a><em></em> <strong>surface</strong> <em>(<var>hax</var>, …)</em></dt>
<dt><a name="index-surface-6"></a><em><var>h</var> =</em> <strong>surface</strong> <em>(…)</em></dt>
<dd><p>Create a surface graphic object given matrices <var>x</var> and <var>y</var> from
<code>meshgrid</code> and a matrix of values <var>z</var> corresponding to the
<var>x</var> and <var>y</var> coordinates of the surface.
</p>
<p>If <var>x</var> and <var>y</var> are vectors, then a typical vertex is
(<var>x</var>(j), <var>y</var>(i), <var>z</var>(i,j)). Thus, columns of <var>z</var> correspond
to different <var>x</var> values and rows of <var>z</var> correspond to different
<var>y</var> values. If only a single input <var>z</var> is given then <var>x</var> is
taken to be <code>1:columns (<var>z</var>)</code> and <var>y</var> is
<code>1:rows (<var>z</var>)</code>.
</p>
<p>Any property/value input pairs are assigned to the surface object.
</p>
<p>If the first argument <var>hax</var> is an axes handle, then plot into this axes,
rather than the current axes returned by <code>gca</code>.
</p>
<p>The optional return value <var>h</var> is a graphics handle to the created
surface object.
</p>
<p>Programming Note: The full list of properties is documented at
<a href="Surface-Properties.html#Surface-Properties">Surface Properties</a>.
</p>
<p><strong>See also:</strong> <a href="Three_002dDimensional-Plots.html#XREFsurf">surf</a>, <a href="Three_002dDimensional-Plots.html#XREFmesh">mesh</a>, <a href="#XREFpatch">patch</a>, <a href="#XREFline">line</a>.
</p></dd></dl>
<a name="XREFlight"></a><dl>
<dt><a name="index-light"></a><em></em> <strong>light</strong> <em>()</em></dt>
<dt><a name="index-light-1"></a><em></em> <strong>light</strong> <em>(…, "<var>prop</var>", <var>val</var>, …)</em></dt>
<dt><a name="index-light-2"></a><em></em> <strong>light</strong> <em>(<var>hax</var>, …)</em></dt>
<dt><a name="index-light-3"></a><em><var>h</var> =</em> <strong>light</strong> <em>(…)</em></dt>
<dd><p>Create a light object in the current axes or for axes <var>hax</var>.
</p>
<p>When a light object is present in an axes object, and the properties
<code>"EdgeLighting"</code> or <code>"FaceLighting"</code> of a <code>patch</code> or
<code>surface</code> object are set to a value other than <code>"none"</code>, these
objects are drawn with lighting effects. Supported values for Lighting
properties are <code>"none"</code> (no lighting effects), <code>"flat"</code> (faceted
look of the objects), and <code>"gouraud"</code> (linear interpolation of the
lighting effects between the vertices). If the lighting mode is set to
<code>"flat"</code>, the <code>"FaceNormals"</code> property is used for lighting.
For <code>"gouraud"</code>, the <code>"VertexNormals"</code> property is used.
</p>
<p>Up to eight light objects are supported per axes. (Implementation
dependent)
</p>
<p>Lighting is only supported for OpenGL graphic toolkits (i.e., <code>"fltk"</code>
and <code>"qt"</code>).
</p>
<p>A light object has the following properties which alter the appearance of
the plot.
</p>
<dl compact="compact">
<dt><code>"Color":</code> The color of the light can be passed as an</dt>
<dd><p>RGB-vector (e.g., <code>[1 0 0]</code> for red) or as a string (e.g., <code>"r"</code>
for red). The default color is white (<code>[1 1 1]</code>).
</p>
</dd>
<dt><code>"Position":</code> The direction from which the light emanates as a</dt>
<dd><p>1x3-vector. The default direction is <code>[1 0 1]</code>.
</p>
</dd>
<dt><code>"Style":</code> This string defines whether the light emanates from a</dt>
<dd><p>light source at infinite distance (<code>"infinite"</code>) or from a local point
source (<code>"local"</code>). The default is <code>"infinite"</code>.
</p></dd>
</dl>
<p>If the first argument <var>hax</var> is an axes handle, then add the light object
to this axes, rather than the current axes returned by <code>gca</code>.
</p>
<p>The optional return value <var>h</var> is a graphics handle to the created light
object.
</p>
<p>Programming Note: The full list of properties is documented at
<a href="Light-Properties.html#Light-Properties">Light Properties</a>.
</p>
<p><strong>See also:</strong> <a href="Three_002dDimensional-Plots.html#XREFlighting">lighting</a>, <a href="Three_002dDimensional-Plots.html#XREFmaterial">material</a>, <a href="#XREFpatch">patch</a>, <a href="#XREFsurface">surface</a>.
</p></dd></dl>
<a name="Handle-Functions"></a>
<h4 class="subsubsection">15.3.2.2 Handle Functions</h4>
<a name="index-handle-functions"></a>
<p>To determine whether a variable is a graphics object index, or an index
to an axes or figure, use the functions <code>ishghandle</code>, <code>isgraphics</code>,
<code>isaxes</code>, and <code>isfigure</code>.
</p>
<a name="XREFishghandle"></a><dl>
<dt><a name="index-ishghandle"></a><em></em> <strong>ishghandle</strong> <em>(<var>h</var>)</em></dt>
<dd><p>Return true if <var>h</var> is a graphics handle and false otherwise.
</p>
<p><var>h</var> may also be a matrix of handles in which case a logical array is
returned that is true where the elements of <var>h</var> are graphics handles and
false where they are not.
</p>
<p><strong>See also:</strong> <a href="#XREFisgraphics">isgraphics</a>, <a href="#XREFisaxes">isaxes</a>, <a href="#XREFisfigure">isfigure</a>, <a href="#XREFishandle">ishandle</a>.
</p></dd></dl>
<a name="XREFisgraphics"></a><dl>
<dt><a name="index-isgraphics"></a><em></em> <strong>isgraphics</strong> <em>(<var>h</var>)</em></dt>
<dt><a name="index-isgraphics-1"></a><em></em> <strong>isgraphics</strong> <em>(<var>h</var>, <var>type</var>)</em></dt>
<dd><p>Return true if <var>h</var> is a graphics handle (of type <var>type</var>) and false
otherwise.
</p>
<p>When no <var>type</var> is specified the function is equivalent to
<code>ishghandle</code>.
</p>
<p><strong>See also:</strong> <a href="#XREFishghandle">ishghandle</a>, <a href="#XREFishandle">ishandle</a>, <a href="#XREFisaxes">isaxes</a>, <a href="#XREFisfigure">isfigure</a>.
</p></dd></dl>
<a name="XREFishandle"></a><dl>
<dt><a name="index-ishandle"></a><em></em> <strong>ishandle</strong> <em>(<var>h</var>)</em></dt>
<dd><p>Return true if <var>h</var> is a handle to a graphics or Java object and false
otherwise.
</p>
<p><var>h</var> may also be a matrix of handles in which case a logical array is
returned that is true where the elements of <var>h</var> are handles to graphics
or Java objects and false where they are not.
</p>
<p>Programming Note: It is often more useful to test for a specific object
type. To determine if a handle belongs to a graphics object use
<code>ishghandle</code> or <code>isgraphics</code>. To determine if a handle belongs
to a Java object use <code>isjava</code>.
</p>
<p><strong>See also:</strong> <a href="#XREFishghandle">ishghandle</a>, <a href="#XREFisgraphics">isgraphics</a>, <a href="Java-Interface-Functions.html#XREFisjava">isjava</a>.
</p></dd></dl>
<a name="XREFisaxes"></a><dl>
<dt><a name="index-isaxes"></a><em></em> <strong>isaxes</strong> <em>(<var>h</var>)</em></dt>
<dd><p>Return true if <var>h</var> is an axes graphics handle and false otherwise.
</p>
<p>If <var>h</var> is a matrix then return a logical array which is true where the
elements of <var>h</var> are axes graphics handles and false where they are not.
</p>
<p><strong>See also:</strong> <a href="#XREFisfigure">isfigure</a>, <a href="#XREFishghandle">ishghandle</a>, <a href="#XREFisgraphics">isgraphics</a>.
</p></dd></dl>
<a name="XREFisfigure"></a><dl>
<dt><a name="index-isfigure"></a><em></em> <strong>isfigure</strong> <em>(<var>h</var>)</em></dt>
<dd><p>Return true if <var>h</var> is a figure graphics handle and false otherwise.
</p>
<p>If <var>h</var> is a matrix then return a logical array which is true where the
elements of <var>h</var> are figure graphics handles and false where they are
not.
</p>
<p><strong>See also:</strong> <a href="#XREFisaxes">isaxes</a>, <a href="#XREFishghandle">ishghandle</a>, <a href="#XREFisgraphics">isgraphics</a>.
</p></dd></dl>
<p>The function <code>gcf</code> returns an index to the current figure object,
or creates one if none exists. Similarly, <code>gca</code> returns the
current axes object, or creates one (and its parent figure object) if
none exists.
</p>
<a name="XREFgroot"></a><dl>
<dt><a name="index-groot"></a><em><var>h</var> =</em> <strong>groot</strong> <em>()</em></dt>
<dd><p>Return a handle to the root graphics object.
</p>
<p>The root graphics object is the ultimate parent of all graphics objects.
</p>
<p>In addition, the root object contains information about the graphics
system as a whole such as the <code>ScreenSize</code>. Use <code>get (groot)</code><!-- /@w -->
to find out what information is available.
</p>
<p>Defaults for the graphic system as a whole are specified by setting
properties of the root graphics object that begin with <code>"Default"</code>.
For example, to set the default font for all text objects to FreeSans use
</p>
<div class="example">
<pre class="example">set (groot, "DefaultTextFontName", "FreeSans")
</pre></div>
<p>Default properties can be deleted by using <code>set</code> with the special
property value of <code>"remove"</code>. To undo the default font assignment
above use
</p>
<div class="example">
<pre class="example">set (groot, "DefaultTextFontName", "remove")
</pre></div>
<p>Programming Note: The root graphics object is identified by the special
handle value of 0. At some point this unique value may change, but code can
be made resistant to future changes by using <code>groot</code> which is
guaranteed to always return the root graphics object.
</p>
<p><strong>See also:</strong> <a href="#XREFgcf">gcf</a>, <a href="#XREFgca">gca</a>, <a href="#XREFget">get</a>, <a href="#XREFset">set</a>.
</p></dd></dl>
<a name="XREFgcf"></a><dl>
<dt><a name="index-gcf"></a><em><var>h</var> =</em> <strong>gcf</strong> <em>()</em></dt>
<dd><p>Return a handle to the current figure.
</p>
<p>The current figure is the default target for graphics output. If multiple
figures exist, <code>gcf</code> returns the last created figure or the last figure
that was clicked on with the mouse.
</p>
<p>If a current figure does not exist, create one and return its handle. The
handle may then be used to examine or set properties of the figure. For
example,
</p>
<div class="example">
<pre class="example">fplot (@sin, [-10, 10]);
fig = gcf ();
set (fig, "numbertitle", "off", "name", "sin plot")
</pre></div>
<p>plots a sine wave, finds the handle of the current figure, and then
renames the figure window to describe the contents.
</p>
<p>Note: To find the current figure without creating a new one if it does not
exist, query the <code>"CurrentFigure"</code> property of the root graphics
object.
</p>
<div class="example">
<pre class="example">get (groot, "currentfigure");
</pre></div>
<p><strong>See also:</strong> <a href="#XREFgca">gca</a>, <a href="#XREFgco">gco</a>, <a href="Callbacks.html#XREFgcbf">gcbf</a>, <a href="Callbacks.html#XREFgcbo">gcbo</a>, <a href="#XREFget">get</a>, <a href="#XREFset">set</a>.
</p></dd></dl>
<a name="XREFgca"></a><dl>
<dt><a name="index-gca"></a><em><var>h</var> =</em> <strong>gca</strong> <em>()</em></dt>
<dd><p>Return a handle to the current axes object.
</p>
<p>The current axes is the default target for graphics output. In the case
of a figure with multiple axes, <code>gca</code> returns the last created axes
or the last axes that was clicked on with the mouse.
</p>
<p>If no current axes object exists, create one and return its handle. The
handle may then be used to examine or set properties of the axes. For
example,
</p>
<div class="example">
<pre class="example">ax = gca ();
set (ax, "position", [0.5, 0.5, 0.5, 0.5]);
</pre></div>
<p>creates an empty axes object and then changes its location and size in the
figure window.
</p>
<p>Note: To find the current axes without creating a new axes object if it
does not exist, query the <code>"CurrentAxes"</code> property of a figure.
</p>
<div class="example">
<pre class="example">get (gcf, "currentaxes");
</pre></div>
<p><strong>See also:</strong> <a href="#XREFgcf">gcf</a>, <a href="#XREFgco">gco</a>, <a href="Callbacks.html#XREFgcbf">gcbf</a>, <a href="Callbacks.html#XREFgcbo">gcbo</a>, <a href="#XREFget">get</a>, <a href="#XREFset">set</a>.
</p></dd></dl>
<a name="XREFgco"></a><dl>
<dt><a name="index-gco"></a><em><var>h</var> =</em> <strong>gco</strong> <em>()</em></dt>
<dt><a name="index-gco-1"></a><em><var>h</var> =</em> <strong>gco</strong> <em>(<var>fig</var>)</em></dt>
<dd><p>Return a handle to the current object of the current figure, or a handle
to the current object of the figure with handle <var>fig</var>.
</p>
<p>The current object of a figure is the object that was last clicked on. It
is stored in the <code>"CurrentObject"</code> property of the target figure.
</p>
<p>If the last mouse click did not occur on any child object of the figure,
then the current object is the figure itself.
</p>
<p>If no mouse click occurred in the target figure, this function returns an
empty matrix.
</p>
<p>Programming Note: The value returned by this function is not necessarily the
same as the one returned by <code>gcbo</code> during callback execution. An
executing callback can be interrupted by another callback and the current
object may be changed.
</p>
<p><strong>See also:</strong> <a href="Callbacks.html#XREFgcbo">gcbo</a>, <a href="#XREFgca">gca</a>, <a href="#XREFgcf">gcf</a>, <a href="Callbacks.html#XREFgcbf">gcbf</a>, <a href="#XREFget">get</a>, <a href="#XREFset">set</a>.
</p></dd></dl>
<p>The <code>get</code> and <code>set</code> functions may be used to examine and set
properties for graphics objects. For example,
</p>
<div class="example">
<pre class="example">get (groot)
⇒ ans =
{
type = root
currentfigure = [](0x0)
children = [](0x0)
visible = on
…
}
</pre></div>
<p>returns a structure containing all the properties of the root figure.
As with all functions in Octave, the structure is returned by value, so
modifying it will not modify the internal root figure plot object. To
do that, you must use the <code>set</code> function. Also, note that in this
case, the <code>currentfigure</code> property is empty, which indicates that
there is no current figure window.
</p>
<p>The <code>get</code> function may also be used to find the value of a single
property. For example,
</p>
<div class="example">
<pre class="example">get (gca (), "xlim")
⇒ [ 0 1 ]
</pre></div>
<p>returns the range of the x-axis for the current axes object in the
current figure.
</p>
<p>To set graphics object properties, use the set function. For example,
</p>
<div class="example">
<pre class="example">set (gca (), "xlim", [-10, 10]);
</pre></div>
<p>sets the range of the x-axis for the current axes object in the current
figure to ‘<samp>[-10, 10]</samp>’.
</p>
<p>Default property values can also be queried if the <code>set</code> function is
called without a value argument. When only one argument is given (a graphic
handle) then a structure with defaults for all properties of the given object
type is returned. For example,
</p>
<div class="example">
<pre class="example">set (gca ())
</pre></div>
<p>returns a structure containing the default property values for axes objects.
If <code>set</code> is called with two arguments (a graphic handle and a property
name) then only the defaults for the requested property are returned.
</p>
<a name="XREFget"></a><dl>
<dt><a name="index-get"></a><em><var>val</var> =</em> <strong>get</strong> <em>(<var>h</var>)</em></dt>
<dt><a name="index-get-1"></a><em><var>val</var> =</em> <strong>get</strong> <em>(<var>h</var>, <var>p</var>)</em></dt>
<dd><p>Return the value of the named property <var>p</var> from the graphics handle
<var>h</var>.
</p>
<p>If <var>p</var> is omitted, return the complete property list for <var>h</var>.
</p>
<p>If <var>h</var> is a vector, return a cell array including the property values or
lists respectively.
</p>
<p><strong>See also:</strong> <a href="#XREFset">set</a>.
</p></dd></dl>
<a name="XREFset"></a><dl>
<dt><a name="index-set"></a><em></em> <strong>set</strong> <em>(<var>h</var>, <var>property</var>, <var>value</var>, …)</em></dt>
<dt><a name="index-set-1"></a><em></em> <strong>set</strong> <em>(<var>h</var>, <var>properties</var>, <var>values</var>)</em></dt>
<dt><a name="index-set-2"></a><em></em> <strong>set</strong> <em>(<var>h</var>, <var>pv</var>)</em></dt>
<dt><a name="index-set-3"></a><em><var>value_list</var> =</em> <strong>set</strong> <em>(<var>h</var>, <var>property</var>)</em></dt>
<dt><a name="index-set-4"></a><em><var>all_value_list</var> =</em> <strong>set</strong> <em>(<var>h</var>)</em></dt>
<dd><p>Set named property values for the graphics handle (or vector of graphics
handles) <var>h</var>.
</p>
<p>There are three ways to give the property names and values:
</p>
<ul>
<li> as a comma separated list of <var>property</var>, <var>value</var> pairs
<p>Here, each <var>property</var> is a string containing the property name, each
<var>value</var> is a value of the appropriate type for the property.
</p>
</li><li> as a cell array of strings <var>properties</var> containing property names
and a cell array <var>values</var> containing property values.
<p>In this case, the number of columns of <var>values</var> must match the number of
elements in <var>properties</var>. The first column of <var>values</var> contains
values for the first entry in <var>properties</var>, etc. The number of rows of
<var>values</var> must be 1 or match the number of elements of <var>h</var>. In the
first case, each handle in <var>h</var> will be assigned the same values. In the
latter case, the first handle in <var>h</var> will be assigned the values from
the first row of <var>values</var> and so on.
</p>
</li><li> as a structure array <var>pv</var>
<p>Here, the field names of <var>pv</var> represent the property names, and the
field values give the property values. In contrast to the previous case,
all elements of <var>pv</var> will be set in all handles in <var>h</var> independent
of the dimensions of <var>pv</var>.
</p></li></ul>
<p><code>set</code> is also used to query the list of values a named property will
take. <code><var>clist</var> = set (<var>h</var>, "property")</code> will return the list
of possible values for <code>"property"</code> in the cell list <var>clist</var>.
If no output variable is used then the list is formatted and printed to the
screen.
</p>
<p>If no property is specified (<code><var>slist</var> = set (<var>h</var>)</code>) then a
structure <var>slist</var> is returned where the fieldnames are the properties of
the object <var>h</var> and the fields are the list of possible values for each
property. If no output variable is used then the list is formatted and
printed to the screen.
</p>
<p>For example,
</p>
<div class="example">
<pre class="example">hf = figure ();
set (hf, "paperorientation")
⇒ [ landscape | {portrait} ]
</pre></div>
<p>shows the paperorientation property can take two values with the default
being <code>"portrait"</code>.
</p>
<p><strong>See also:</strong> <a href="#XREFget">get</a>.
</p></dd></dl>
<a name="XREFancestor"></a><dl>
<dt><a name="index-ancestor"></a><em><var>parent</var> =</em> <strong>ancestor</strong> <em>(<var>h</var>, <var>type</var>)</em></dt>
<dt><a name="index-ancestor-1"></a><em><var>parent</var> =</em> <strong>ancestor</strong> <em>(<var>h</var>, <var>type</var>, "toplevel")</em></dt>
<dd><p>Return the first ancestor of handle object <var>h</var> whose type matches
<var>type</var>, where <var>type</var> is a character string.
</p>
<p>If <var>type</var> is a cell array of strings, return the first parent whose
type matches any of the given type strings.
</p>
<p>If the handle object <var>h</var> itself is of type <var>type</var>, return <var>h</var>.
</p>
<p>If <code>"toplevel"</code> is given as a third argument, return the highest
parent in the object hierarchy that matches the condition, instead
of the first (nearest) one.
</p>
<p><strong>See also:</strong> <a href="Searching-Properties.html#XREFfindobj">findobj</a>, <a href="Searching-Properties.html#XREFfindall">findall</a>, <a href="#XREFallchild">allchild</a>.
</p></dd></dl>
<a name="XREFallchild"></a><dl>
<dt><a name="index-allchild"></a><em><var>h</var> =</em> <strong>allchild</strong> <em>(<var>handles</var>)</em></dt>
<dd><p>Find all children, including hidden children, of a graphics object.
</p>
<p>This function is similar to <code>get (h, "children")</code>, but also returns
hidden objects (HandleVisibility = <code>"off"</code>).
</p>
<p>If <var>handles</var> is a scalar, <var>h</var> will be a vector. Otherwise,
<var>h</var> will be a cell matrix of the same size as <var>handles</var> and each
cell will contain a vector of handles.
</p>
<p><strong>See also:</strong> <a href="Searching-Properties.html#XREFfindall">findall</a>, <a href="Searching-Properties.html#XREFfindobj">findobj</a>, <a href="#XREFget">get</a>, <a href="#XREFset">set</a>.
</p></dd></dl>
<a name="XREFfindfigs"></a><dl>
<dt><a name="index-findfigs"></a><em></em> <strong>findfigs</strong> <em>()</em></dt>
<dd><p>Find all visible figures that are currently off the screen and move them
onto the screen.
</p>
<p><strong>See also:</strong> <a href="#XREFallchild">allchild</a>, <a href="Multiple-Plot-Windows.html#XREFfigure">figure</a>, <a href="#XREFget">get</a>, <a href="#XREFset">set</a>.
</p></dd></dl>
<a name="index-saving-graphics-objects"></a>
<a name="index-graphics-objects_002c-saving"></a>
<p>Figures can be printed or saved in many graphics formats with <code>print</code> and
<code>saveas</code>. Occasionally, however, it may be useful to save the original
Octave handle graphic directly so that further modifications can be made such
as modifying a title or legend.
</p>
<p>This can be accomplished with the following functions by
</p>
<div class="example">
<pre class="example">fig_struct = hdl2struct (gcf);
save myplot.fig -struct fig_struct;
…
fig_struct = load ("myplot.fig");
struct2hdl (fig_struct);
</pre></div>
<a name="XREFhdl2struct"></a><dl>
<dt><a name="index-hdl2struct"></a><em><var>s</var> =</em> <strong>hdl2struct</strong> <em>(<var>h</var>)</em></dt>
<dd><p>Return a structure, <var>s</var>, whose fields describe the properties
of the object, and its children, associated with the handle, <var>h</var>.
</p>
<p>The fields of the structure <var>s</var> are <code>"type"</code>, <code>"handle"</code>,
<code>"properties"</code>, <code>"children"</code>, and <code>"special"</code>.
</p>
<p><strong>See also:</strong> <a href="#XREFstruct2hdl">struct2hdl</a>, <a href="Printing-and-Saving-Plots.html#XREFhgsave">hgsave</a>, <a href="Searching-Properties.html#XREFfindobj">findobj</a>.
</p></dd></dl>
<a name="XREFstruct2hdl"></a><dl>
<dt><a name="index-struct2hdl"></a><em><var>h</var> =</em> <strong>struct2hdl</strong> <em>(<var>s</var>)</em></dt>
<dt><a name="index-struct2hdl-1"></a><em><var>h</var> =</em> <strong>struct2hdl</strong> <em>(<var>s</var>, <var>p</var>)</em></dt>
<dt><a name="index-struct2hdl-2"></a><em><var>h</var> =</em> <strong>struct2hdl</strong> <em>(<var>s</var>, <var>p</var>, <var>hilev</var>)</em></dt>
<dd><p>Construct a graphics handle object <var>h</var> from the structure <var>s</var>.
</p>
<p>The structure must contain the fields <code>"handle"</code>, <code>"type"</code>,
<code>"children"</code>, <code>"properties"</code>, and <code>"special"</code>.
</p>
<p>If the handle of an existing figure or axes is specified, <var>p</var>, the new
object will be created as a child of that object. If no parent handle is
provided then a new figure and the necessary children will be constructed
using the default values from the root figure.
</p>
<p>A third boolean argument <var>hilev</var> can be passed to specify whether the
function should preserve listeners/callbacks, e.g., for legends or
hggroups. The default is false.
</p>
<p><strong>See also:</strong> <a href="#XREFhdl2struct">hdl2struct</a>, <a href="Printing-and-Saving-Plots.html#XREFhgload">hgload</a>, <a href="Searching-Properties.html#XREFfindobj">findobj</a>.
</p></dd></dl>
<a name="XREFcopyobj"></a><dl>
<dt><a name="index-copyobj"></a><em><var>hnew</var> =</em> <strong>copyobj</strong> <em>(<var>horig</var>)</em></dt>
<dt><a name="index-copyobj-1"></a><em><var>hnew</var> =</em> <strong>copyobj</strong> <em>(<var>horig</var>, <var>hparent</var>)</em></dt>
<dd><p>Construct a copy of the graphic objects associated with the handles
<var>horig</var> and return new handles <var>hnew</var> to the new objects.
</p>
<p>If a parent handle <var>hparent</var> (root, figure, axes, or hggroup) is
specified, the copied object will be created as a child of <var>hparent</var>.
</p>
<p>If <var>horig</var> is a vector of handles, and <var>hparent</var> is a scalar,
then each handle in the vector <var>hnew</var> has its <code>"Parent"</code> property
set to <var>hparent</var>. Conversely, if <var>horig</var> is a scalar and
<var>hparent</var> a vector, then each parent object will receive a copy of
<var>horig</var>. If <var>horig</var> and <var>hparent</var> are both vectors with the
same number of elements then <code><var>hnew</var>(i)</code> will have parent
<code><var>hparent</var>(i)</code>.
</p>
<p><strong>See also:</strong> <a href="#XREFstruct2hdl">struct2hdl</a>, <a href="#XREFhdl2struct">hdl2struct</a>, <a href="Searching-Properties.html#XREFfindobj">findobj</a>.
</p></dd></dl>
<hr>
<div class="header">
<p>
Next: <a href="Graphics-Object-Properties.html#Graphics-Object-Properties" accesskey="n" rel="next">Graphics Object Properties</a>, Previous: <a href="Introduction-to-Graphics-Structures.html#Introduction-to-Graphics-Structures" accesskey="p" rel="prev">Introduction to Graphics Structures</a>, Up: <a href="Graphics-Data-Structures.html#Graphics-Data-Structures" accesskey="u" rel="up">Graphics Data Structures</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
</div>
</body>
</html>
