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

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<h3><a href="../contents.html">Table Of Contents</a></h3>

<ul>

<li><a class="reference internal" href="#">Annotating Axes</a><ul>

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

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

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

<li><a class="reference internal" href="#using-complex-coordinate-with-annotation">Using Complex Coordinate with Annotation</a></li>

<li><a class="reference internal" href="#using-connectorpatch">Using ConnectorPatch</a><ul>

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

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<h1>Annotating Axes<a class="headerlink" href="#annotating-axes" title="Permalink to this headline">¶</a></h1>

Do not proceed unless you already have read <a class="reference internal" href="annotations_intro.html#annotations-tutorial">Annotating text</a>,

<a class="reference internal" href="../api/pyplot_api.html#matplotlib.pyplot.text" title="matplotlib.pyplot.text"><tt class="xref py py-func docutils literal">text()</tt></a> and

<a class="reference internal" href="../api/pyplot_api.html#matplotlib.pyplot.annotate" title="matplotlib.pyplot.annotate"><tt class="xref py py-func docutils literal">annotate()</tt></a>!

<h2>Annotating with Text with Box<a class="headerlink" href="#annotating-with-text-with-box" title="Permalink to this headline">¶</a></h2>

Let’s start with a simple example.

(<a class="reference external" href="../users/plotting/examples/annotate_text_arrow.py">Source code</a>, <a class="reference external" href="../users/plotting/examples/annotate_text_arrow.png">png</a>, <a class="reference external" href="../users/plotting/examples/annotate_text_arrow.hires.png">hires.png</a>, <a class="reference external" href="../users/plotting/examples/annotate_text_arrow.pdf">pdf</a>)

</div>

The <a class="reference internal" href="../api/pyplot_api.html#matplotlib.pyplot.text" title="matplotlib.pyplot.text"><tt class="xref py py-func docutils literal">text()</tt></a> function in the pyplot module (or

text method of the Axes class) takes bbox keyword argument, and when

given, a box around the text is drawn.

<div class="highlight-python"><div class="highlight"><pre>bbox_props = dict(boxstyle="rarrow,pad=0.3", fc="cyan", ec="b", lw=2)

t = ax.text(0, 0, "Direction", ha="center", va="center", rotation=45,

size=15,

bbox=bbox_props)

</pre></div>

</div>

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

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

</pre></div>

</div>

The return value is an instance of FancyBboxPatch and the patch

properties like facecolor, edgewidth, etc. can be accessed and

modified as usual. To change the shape of the box, use set_boxstyle

method.

<div class="highlight-python"><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>

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

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

</tr>

</thead>

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

<td><tt class="docutils literal">larrow</tt></td>

</tr>

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

<td><tt class="docutils literal">rarrow</tt></td>

</tr>

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

<td><tt class="docutils literal">round</tt></td>

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

</tr>

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

<td><tt class="docutils literal">round4</tt></td>

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

</tr>

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

<td><tt class="docutils literal">roundtooth</tt></td>

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

</tr>

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

<td><tt class="docutils literal">sawtooth</tt></td>

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

</tr>

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

<td><tt class="docutils literal">square</tt></td>

</tr>

</tbody>

</table>

</div></blockquote>

(<a class="reference external" href="../mpl_examples/pylab_examples/fancybox_demo2.py">Source code</a>, <a class="reference external" href="../mpl_examples/pylab_examples/fancybox_demo2.png">png</a>, <a class="reference external" href="../mpl_examples/pylab_examples/fancybox_demo2.hires.png">hires.png</a>, <a class="reference external" href="../mpl_examples/pylab_examples/fancybox_demo2.pdf">pdf</a>)

</div>

Note that the attributes 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>

<h2>Annotating with Arrow<a class="headerlink" href="#annotating-with-arrow" title="Permalink to this headline">¶</a></h2>

The <a class="reference internal" href="../api/pyplot_api.html#matplotlib.pyplot.annotate" title="matplotlib.pyplot.annotate"><tt class="xref py py-func docutils literal">annotate()</tt></a> function in the pyplot module

(or annotate method of the Axes class) is used to draw an arrow

connecting two points on the plot.

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

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

)

</pre></div>

</div>

This annotates a point at <tt class="docutils literal">xy</tt> in the given coordinate (<tt class="docutils literal">xycoords</tt>)

with the text at <tt class="docutils literal">xytext</tt> given in <tt class="docutils literal">textcoords</tt>. Often, the

annotated point is specified in the data coordinate and the annotating

text in offset points.

See <a class="reference internal" href="../api/pyplot_api.html#matplotlib.pyplot.annotate" title="matplotlib.pyplot.annotate"><tt class="xref py py-func docutils literal">annotate()</tt></a> for available coordinate systems.

An arrow connecting two point (xy & xytext) can be optionally drawn by

specifying the <tt class="docutils literal">arrowprops</tt> 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>

(<a class="reference external" href="../users/plotting/examples/annotate_simple01.py">Source code</a>, <a class="reference external" href="../users/plotting/examples/annotate_simple01.png">png</a>, <a class="reference external" href="../users/plotting/examples/annotate_simple01.hires.png">hires.png</a>, <a class="reference external" href="../users/plotting/examples/annotate_simple01.pdf">pdf</a>)

</div>

The arrow drawing takes a few steps.

<li>a connecting path between two points are created. This is

controlled by <tt class="docutils literal">connectionstyle</tt> key value.</li>

<li>If patch object is given (patchA & patchB), the path is clipped to

avoid the patch.</li>

<li>The path is further shrunk by given amount of pixels (shirnkA

& shrinkB)</li>

<li>The path is transmuted to arrow patch, which is controlled by the

<tt class="docutils literal">arrowstyle</tt> key value.</li>

</ol>

(<a class="reference external" href="../users/plotting/examples/annotate_explain.py">Source code</a>, <a class="reference external" href="../users/plotting/examples/annotate_explain.png">png</a>, <a class="reference external" href="../users/plotting/examples/annotate_explain.hires.png">hires.png</a>, <a class="reference external" href="../users/plotting/examples/annotate_explain.pdf">pdf</a>)

</div>

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

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

</colgroup>

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

</tr>

</thead>

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

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

</tr>

<tr class="row-odd"><td><tt class="docutils literal">angle3</tt></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 <tt class="docutils literal">angle3</tt> and <tt class="docutils literal">arc3</tt> is meant to indicate that the

resulting path is a quadratic spline segment (three control

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

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 <tt class="docutils literal">bar</tt> style is currently not

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

(<a class="reference external" href="../users/plotting/examples/connectionstyle_demo.py">Source code</a>, <a class="reference external" href="../users/plotting/examples/connectionstyle_demo.png">png</a>, <a class="reference external" href="../users/plotting/examples/connectionstyle_demo.hires.png">hires.png</a>, <a class="reference external" href="../users/plotting/examples/connectionstyle_demo.pdf">pdf</a>)

</div>

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

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

</colgroup>

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

</tr>

</thead>

</tr>