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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"

"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<head>

<title>Annotations — Matplotlib 3.5.1 documentation</title>

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Basic annotation

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Advanced Annotations

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Annotating with Text with Box

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Annotating with Arrow

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Placing Artist at the anchored location of the Axes

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Note

Click <a class="reference internal" href="#sphx-glr-download-tutorials-text-annotations-py">here</a>

to download the full example code

</div>

<h1><a class="toc-backref" href="#id1">Annotations</a><a class="headerlink" href="#annotations" title="Permalink to this headline">¶</a></h1>

Annotating text with Matplotlib.

Table of Contents

<li><a class="reference internal" href="#annotations" id="id1">Annotations</a>

<ul>

<li><a class="reference internal" href="#basic-annotation" id="id2">Basic annotation</a></li>

<li><a class="reference internal" href="#advanced-annotations" id="id3">Advanced Annotations</a>

<ul>

<li><a class="reference internal" href="#annotating-with-text-with-box" id="id4">Annotating with Text with Box</a></li>

<li><a class="reference internal" href="#annotating-with-arrow" id="id5">Annotating with Arrow</a></li>

<li><a class="reference internal" href="#placing-artist-at-the-anchored-location-of-the-axes" id="id6">Placing Artist at the anchored location of the Axes</a></li>

<li><a class="reference internal" href="#using-complex-coordinates-with-annotations" id="id7">Using Complex Coordinates with Annotations</a></li>

<li><a class="reference internal" href="#using-connectionpatch" id="id8">Using ConnectionPatch</a></li>

</ul>

</li>

<li><a class="reference internal" href="#advanced-topics" id="id9">Advanced Topics</a>

<ul>

<li><a class="reference internal" href="#zoom-effect-between-axes" id="id10">Zoom effect between Axes</a></li>

<li><a class="reference internal" href="#define-custom-boxstyle" id="id11">Define Custom BoxStyle</a></li>

</ul>

</li>

</ul>

</li>

</ul>

</div>

<div class="highlight-default notranslate"><div class="highlight"><pre>from matplotlib import pyplot as plt

</pre></div>

</div>

<h2><a class="toc-backref" href="#id2">Basic annotation</a><a class="headerlink" href="#basic-annotation" title="Permalink to this headline">¶</a></h2>

The uses of the basic <a class="reference internal" href="../../api/_as_gen/matplotlib.pyplot.text.html#matplotlib.pyplot.text" title="matplotlib.pyplot.text"><code class="xref py py-func docutils literal notranslate">text()</code></a> will place text

at an arbitrary position on the Axes. A common use case of text is to

annotate some feature of the plot, and the

<a class="reference internal" href="../../api/_as_gen/matplotlib.axes.Axes.annotate.html#matplotlib.axes.Axes.annotate" title="matplotlib.axes.Axes.annotate"><code class="xref py py-func docutils literal notranslate">annotate()</code></a> method provides helper functionality

to make annotations easy. In an annotation, there are two points to

consider: the location being annotated represented by the argument

xy and the location of the text xytext. Both of these

arguments are <code class="docutils literal notranslate">(x, y)</code> tuples.

</figure>

In this example, both the xy (arrow tip) and xytext locations

(text location) are in data coordinates. There are a variety of other

coordinate systems one can choose -- you can specify the coordinate

system of xy and xytext with one of the following strings for

xycoords and textcoords (default is 'data')

</colgroup>

<thead>

<tr class="row-odd"><th class="head">argument</th>

<th class="head">coordinate system</th>

</tr>

</thead>

<tbody>

<tr class="row-even"><td>'figure points'</td>

<td>points from the lower left corner of the figure</td>

</tr>

<tr class="row-odd"><td>'figure pixels'</td>

<td>pixels from the lower left corner of the figure</td>

</tr>

<tr class="row-even"><td>'figure fraction'</td>

<td>(0, 0) is lower left of figure and (1, 1) is upper right</td>

</tr>

<tr class="row-odd"><td>'axes points'</td>

<td>points from lower left corner of axes</td>

</tr>

<tr class="row-even"><td>'axes pixels'</td>

<td>pixels from lower left corner of axes</td>

</tr>

<tr class="row-odd"><td>'axes fraction'</td>

<td>(0, 0) is lower left of axes and (1, 1) is upper right</td>

</tr>

<td>use the axes data coordinate system</td>

</tr>

</tbody>

</table>

For example to place the text coordinates in fractional axes

coordinates, one could do:

<div class="highlight-default notranslate"><div class="highlight"><pre>ax.annotate('local max', xy=(3, 1), xycoords='data',

xytext=(0.8, 0.95), textcoords='axes fraction',

arrowprops=dict(facecolor='black', shrink=0.05),

horizontalalignment='right', verticalalignment='top',

)

</pre></div>

</div>

For physical coordinate systems (points or pixels) the origin is the

bottom-left of the figure or axes.

Optionally, you can enable drawing of an arrow from the text to the annotated

point by giving a dictionary of arrow properties in the optional keyword

argument arrowprops.

</colgroup>

<thead>

<tr class="row-odd"><th class="head">arrowprops key</th>

<th class="head">description</th>

</tr>

</thead>

<tbody>

<tr class="row-even"><td>width</td>

<td>the width of the arrow in points</td>

</tr>

<td>the fraction of the arrow length occupied by the head</td>

</tr>

<tr class="row-even"><td>headwidth</td>

<td>the width of the base of the arrow head in points</td>

</tr>

<tr class="row-odd"><td>shrink</td>

<td>move the tip and base some percent away from

the annotated point and text</td>

</tr>

<tr class="row-even"><td>**kwargs</td>

<td>any key for <a class="reference internal" href="../../api/_as_gen/matplotlib.patches.Polygon.html#matplotlib.patches.Polygon" title="matplotlib.patches.Polygon"><code class="xref py py-class docutils literal notranslate">matplotlib.patches.Polygon</code></a>,

e.g., <code class="docutils literal notranslate">facecolor</code></td>

</tr>

</tbody>

</table>

In the example below, the xy point is in native coordinates

(xycoords defaults to 'data'). For a polar axes, this is in

(theta, radius) space. The text in this example is placed in the

fractional figure coordinate system. <a class="reference internal" href="../../api/text_api.html#matplotlib.text.Text" title="matplotlib.text.Text"><code class="xref py py-class docutils literal notranslate">matplotlib.text.Text</code></a>

keyword arguments like horizontalalignment, verticalalignment and

fontsize are passed from <a class="reference internal" href="../../api/_as_gen/matplotlib.axes.Axes.annotate.html#matplotlib.axes.Axes.annotate" title="matplotlib.axes.Axes.annotate"><code class="xref py py-obj docutils literal notranslate">annotate</code></a> to the

<code class="docutils literal notranslate">Text</code> instance.

</figure>

For more on all the wild and wonderful things you can do with

annotations, including fancy arrows, see <a class="reference internal" href="#plotting-guide-annotation">Advanced Annotations</a>

and <a class="reference internal" href="../../gallery/text_labels_and_annotations/annotation_demo.html">Annotating Plots</a>.

Do not proceed unless you have already read <a class="reference internal" href="#annotations-tutorial">Basic annotation</a>,

<a class="reference internal" href="../../api/_as_gen/matplotlib.pyplot.text.html#matplotlib.pyplot.text" title="matplotlib.pyplot.text"><code class="xref py py-func docutils literal notranslate">text()</code></a> and <a class="reference internal" href="../../api/_as_gen/matplotlib.pyplot.annotate.html#matplotlib.pyplot.annotate" title="matplotlib.pyplot.annotate"><code class="xref py py-func docutils literal notranslate">annotate()</code></a>!

</section>

<h2><a class="toc-backref" href="#id3">Advanced Annotations</a><a class="headerlink" href="#advanced-annotations" title="Permalink to this headline">¶</a></h2>

<h3><a class="toc-backref" href="#id4">Annotating with Text with Box</a><a class="headerlink" href="#annotating-with-text-with-box" title="Permalink to this headline">¶</a></h3>

Let's start with a simple example.

</figure>

<a class="reference internal" href="../../api/_as_gen/matplotlib.axes.Axes.text.html#matplotlib.axes.Axes.text" title="matplotlib.axes.Axes.text"><code class="xref py py-obj docutils literal notranslate">text</code></a> takes a bbox keyword argument, which draws a box around the

text:

<div class="highlight-default notranslate"><div class="highlight"><pre>t = ax.text(

0, 0, "Direction", ha="center", va="center", rotation=45, size=15,

bbox=dict(boxstyle="rarrow,pad=0.3", fc="cyan", ec="b", lw=2))

</pre></div>

</div>

The patch object associated with the text can be accessed by:

<div class="highlight-default notranslate"><div class="highlight"><pre>bb = t.get_bbox_patch()

</pre></div>

</div>

The return value is a <a class="reference internal" href="../../api/_as_gen/matplotlib.patches.FancyBboxPatch.html#matplotlib.patches.FancyBboxPatch" title="matplotlib.patches.FancyBboxPatch"><code class="xref py py-obj docutils literal notranslate">FancyBboxPatch</code></a>; patch properties

(facecolor, edgewidth, etc.) can be accessed and modified as usual.

<a class="reference internal" href="../../api/_as_gen/matplotlib.patches.FancyBboxPatch.html#matplotlib.patches.FancyBboxPatch.set_boxstyle" title="matplotlib.patches.FancyBboxPatch.set_boxstyle"><code class="xref py py-obj docutils literal notranslate">FancyBboxPatch.set_boxstyle</code></a> sets the box shape:

<div class="highlight-default notranslate"><div class="highlight"><pre>bb.set_boxstyle("rarrow", pad=0.6)

</pre></div>

</div>

The arguments are the name of the box style with its attributes as

keyword arguments. Currently, following box styles are implemented.

</colgroup>

<thead>

<tr class="row-odd"><th class="head">Class</th>

<th class="head">Attrs</th>

</tr>

</thead>

<tbody>

<tr class="row-even"><td>Circle</td>

<td><code class="docutils literal notranslate">circle</code></td>

</tr>

<tr class="row-odd"><td>DArrow</td>

<td><code class="docutils literal notranslate">darrow</code></td>

</tr>

<tr class="row-even"><td>LArrow</td>

<td><code class="docutils literal notranslate">larrow</code></td>

</tr>

<tr class="row-odd"><td>RArrow</td>

<td><code class="docutils literal notranslate">rarrow</code></td>

</tr>

<tr class="row-even"><td>Round</td>

<td><code class="docutils literal notranslate">round</code></td>

<td>pad=0.3,rounding_size=None</td>

</tr>

<tr class="row-odd"><td>Round4</td>

<td><code class="docutils literal notranslate">round4</code></td>

<td>pad=0.3,rounding_size=None</td>

</tr>

<tr class="row-even"><td>Roundtooth</td>

<td><code class="docutils literal notranslate">roundtooth</code></td>

<td>pad=0.3,tooth_size=None</td>

</tr>

<tr class="row-odd"><td>Sawtooth</td>

<td><code class="docutils literal notranslate">sawtooth</code></td>

<td>pad=0.3,tooth_size=None</td>

</tr>

<tr class="row-even"><td>Square</td>

<td><code class="docutils literal notranslate">square</code></td>

</tr>

</tbody>

</table>

</div></blockquote>

</figure>

Note that the attribute arguments can be specified within the style

name with separating comma (this form can be used as "boxstyle" value

of bbox argument when initializing the text instance)

</pre></div>

</div>

</section>

<h3><a class="toc-backref" href="#id5">Annotating with Arrow</a><a class="headerlink" href="#annotating-with-arrow" title="Permalink to this headline">¶</a></h3>

<a class="reference internal" href="../../api/_as_gen/matplotlib.axes.Axes.annotate.html#matplotlib.axes.Axes.annotate" title="matplotlib.axes.Axes.annotate"><code class="xref py py-obj docutils literal notranslate">annotate</code></a> draws an arrow connecting two points in an axes:

xy=(x1, y1), xycoords='data',

xytext=(x2, y2), textcoords='offset points',

)

</pre></div>

</div>

This annotates a point at xy in the given coordinate (xycoords)

with the text at xytext given in textcoords. Often, the

annotated point is specified in the data coordinate and the annotating

text in offset points.

See <a class="reference internal" href="../../api/_as_gen/matplotlib.axes.Axes.annotate.html#matplotlib.axes.Axes.annotate" title="matplotlib.axes.Axes.annotate"><code class="xref py py-obj docutils literal notranslate">annotate</code></a> for available coordinate systems.

An arrow connecting xy to xytext can be optionally drawn by

specifying the arrowprops argument. To draw only an arrow, use

empty string as the first argument.

xy=(0.2, 0.2), xycoords='data',

xytext=(0.8, 0.8), textcoords='data',

arrowprops=dict(arrowstyle="->",

connectionstyle="arc3"),

)

</pre></div>

</div>

</figure>

The arrow is drawn as follows:

<li>A path connecting the two points is created, as specified by the

connectionstyle parameter.</li>

<li>The path is clipped to avoid patches patchA and patchB, if these are

set.</li>

<li>The path is further shrunk by shrinkA and shrinkB (in pixels).</li>

<li>The path is transmuted to an arrow patch, as specified by the arrowstyle

parameter.</li>

</ol>

</figure>

The creation of the connecting path between two points is controlled by

<code class="docutils literal notranslate">connectionstyle</code> key and the following styles are available.

</colgroup>

<thead>

<th class="head">Attrs</th>

</tr>

</thead>

<tbody>

<tr class="row-even"><td><code class="docutils literal notranslate">angle</code></td>

<td>angleA=90,angleB=0,rad=0.0</td>

</tr>

<tr class="row-odd"><td><code class="docutils literal notranslate">angle3</code></td>

<td>angleA=90,angleB=0</td>

</tr>

<td>angleA=0,angleB=0,armA=None,armB=None,rad=0.0</td>

</tr>

</tr>

<td>armA=0.0,armB=0.0,fraction=0.3,angle=None</td>

</tr>

</tbody>

</table>

</div></blockquote>

Note that "3" in <code class="docutils literal notranslate">angle3</code> and <code class="docutils literal notranslate">arc3</code> is meant to indicate that the

resulting path is a quadratic spline segment (three control

points). As will be discussed below, some arrow style options can only

be used when the connecting path is a quadratic spline.

The behavior of each connection style is (limitedly) demonstrated in the

example below. (Warning: The behavior of the <code class="docutils literal notranslate">bar</code> style is currently not

well defined, it may be changed in the future).

</figure>

The connecting path (after clipping and shrinking) is then mutated to

an arrow patch, according to the given <code class="docutils literal notranslate">arrowstyle</code>.

</colgroup>

<thead>

<th class="head">Attrs</th>

</tr>

</thead>

<tbody>

</tr>