.. DO NOT EDIT. .. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY. .. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE: .. "tutorials/text/annotations.py" .. LINE NUMBERS ARE GIVEN BELOW. .. only:: html .. meta:: :keywords: codex .. note:: :class: sphx-glr-download-link-note Click :ref:`here ` to download the full example code .. rst-class:: sphx-glr-example-title .. _sphx_glr_tutorials_text_annotations.py: Annotations =========== Annotating text with Matplotlib. .. contents:: Table of Contents :depth: 3 .. GENERATED FROM PYTHON SOURCE LINES 10-13 .. code-block:: default from matplotlib import pyplot as plt .. GENERATED FROM PYTHON SOURCE LINES 14-291 .. _annotations-tutorial: Basic annotation ---------------- The uses of the basic :func:`~matplotlib.pyplot.text` 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 :func:`~matplotlib.axes.Axes.annotate` 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 ``(x, y)`` tuples. .. figure:: ../../gallery/pyplots/images/sphx_glr_annotation_basic_001.png :target: ../../gallery/pyplots/annotation_basic.html :align: center 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') ================== ======================================================== argument coordinate system ================== ======================================================== 'figure points' points from the lower left corner of the figure 'figure pixels' pixels from the lower left corner of the figure 'figure fraction' (0, 0) is lower left of figure and (1, 1) is upper right 'axes points' points from lower left corner of axes 'axes pixels' pixels from lower left corner of axes 'axes fraction' (0, 0) is lower left of axes and (1, 1) is upper right 'data' use the axes data coordinate system ================== ======================================================== For example to place the text coordinates in fractional axes coordinates, one could do:: 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', ) 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*. ==================== ===================================================== *arrowprops* key description ==================== ===================================================== width the width of the arrow in points frac the fraction of the arrow length occupied by the head headwidth the width of the base of the arrow head in points shrink move the tip and base some percent away from the annotated point and text \*\*kwargs any key for :class:`matplotlib.patches.Polygon`, e.g., ``facecolor`` ==================== ===================================================== 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. :class:`matplotlib.text.Text` keyword arguments like *horizontalalignment*, *verticalalignment* and *fontsize* are passed from `~matplotlib.axes.Axes.annotate` to the ``Text`` instance. .. figure:: ../../gallery/pyplots/images/sphx_glr_annotation_polar_001.png :target: ../../gallery/pyplots/annotation_polar.html :align: center For more on all the wild and wonderful things you can do with annotations, including fancy arrows, see :ref:`plotting-guide-annotation` and :doc:`/gallery/text_labels_and_annotations/annotation_demo`. Do not proceed unless you have already read :ref:`annotations-tutorial`, :func:`~matplotlib.pyplot.text` and :func:`~matplotlib.pyplot.annotate`! .. _plotting-guide-annotation: Advanced Annotations -------------------- Annotating with Text with Box ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Let's start with a simple example. .. figure:: ../../gallery/userdemo/images/sphx_glr_annotate_text_arrow_001.png :target: ../../gallery/userdemo/annotate_text_arrow.html :align: center `~.Axes.text` takes a *bbox* keyword argument, which draws a box around the text:: 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)) The patch object associated with the text can be accessed by:: bb = t.get_bbox_patch() The return value is a `.FancyBboxPatch`; patch properties (facecolor, edgewidth, etc.) can be accessed and modified as usual. `.FancyBboxPatch.set_boxstyle` sets the box shape:: bb.set_boxstyle("rarrow", pad=0.6) The arguments are the name of the box style with its attributes as keyword arguments. Currently, following box styles are implemented. ========== ============== ========================== Class Name Attrs ========== ============== ========================== Circle ``circle`` pad=0.3 DArrow ``darrow`` pad=0.3 LArrow ``larrow`` pad=0.3 RArrow ``rarrow`` pad=0.3 Round ``round`` pad=0.3,rounding_size=None Round4 ``round4`` pad=0.3,rounding_size=None Roundtooth ``roundtooth`` pad=0.3,tooth_size=None Sawtooth ``sawtooth`` pad=0.3,tooth_size=None Square ``square`` pad=0.3 ========== ============== ========================== .. figure:: ../../gallery/shapes_and_collections/images/sphx_glr_fancybox_demo_001.png :target: ../../gallery/shapes_and_collections/fancybox_demo.html :align: center 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) :: bb.set_boxstyle("rarrow,pad=0.6") Annotating with Arrow ~~~~~~~~~~~~~~~~~~~~~ `~.Axes.annotate` draws an arrow connecting two points in an Axes:: ax.annotate("Annotation", xy=(x1, y1), xycoords='data', xytext=(x2, y2), textcoords='offset points', ) 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 `~.Axes.annotate` 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. :: ax.annotate("", xy=(0.2, 0.2), xycoords='data', xytext=(0.8, 0.8), textcoords='data', arrowprops=dict(arrowstyle="->", connectionstyle="arc3"), ) .. figure:: ../../gallery/userdemo/images/sphx_glr_annotate_simple01_001.png :target: ../../gallery/userdemo/annotate_simple01.html :align: center The arrow is drawn as follows: 1. A path connecting the two points is created, as specified by the *connectionstyle* parameter. 2. The path is clipped to avoid patches *patchA* and *patchB*, if these are set. 3. The path is further shrunk by *shrinkA* and *shrinkB* (in pixels). 4. The path is transmuted to an arrow patch, as specified by the *arrowstyle* parameter. .. figure:: ../../gallery/userdemo/images/sphx_glr_annotate_explain_001.png :target: ../../gallery/userdemo/annotate_explain.html :align: center The creation of the connecting path between two points is controlled by ``connectionstyle`` key and the following styles are available. ========== ============================================= Name Attrs ========== ============================================= ``angle`` angleA=90,angleB=0,rad=0.0 ``angle3`` angleA=90,angleB=0 ``arc`` angleA=0,angleB=0,armA=None,armB=None,rad=0.0 ``arc3`` rad=0.0 ``bar`` armA=0.0,armB=0.0,fraction=0.3,angle=None ========== ============================================= Note that "3" in ``angle3`` and ``arc3`` 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 ``bar`` style is currently not well defined, it may be changed in the future). .. figure:: ../../gallery/userdemo/images/sphx_glr_connectionstyle_demo_001.png :target: ../../gallery/userdemo/connectionstyle_demo.html :align: center The connecting path (after clipping and shrinking) is then mutated to an arrow patch, according to the given ``arrowstyle``. ========== ============================================= Name Attrs ========== ============================================= ``-`` None ``->`` head_length=0.4,head_width=0.2 ``-[`` widthB=1.0,lengthB=0.2,angleB=None ``|-|`` widthA=1.0,widthB=1.0 ``-|>`` head_length=0.4,head_width=0.2 ``<-`` head_length=0.4,head_width=0.2 ``<->`` head_length=0.4,head_width=0.2 ``<|-`` head_length=0.4,head_width=0.2 ``<|-|>`` head_length=0.4,head_width=0.2 ``fancy`` head_length=0.4,head_width=0.4,tail_width=0.4 ``simple`` head_length=0.5,head_width=0.5,tail_width=0.2 ``wedge`` tail_width=0.3,shrink_factor=0.5 ========== ============================================= .. figure:: ../../gallery/text_labels_and_annotations/images/sphx_glr_fancyarrow_demo_001.png :target: ../../gallery/text_labels_and_annotations/fancyarrow_demo.html :align: center Some arrowstyles only work with connection styles that generate a quadratic-spline segment. They are ``fancy``, ``simple``, and ``wedge``. For these arrow styles, you must use the "angle3" or "arc3" connection style. If the annotation string is given, the patchA is set to the bbox patch of the text by default. .. figure:: ../../gallery/userdemo/images/sphx_glr_annotate_simple02_001.png :target: ../../gallery/userdemo/annotate_simple02.html :align: center As with `~.Axes.text`, a box around the text can be drawn using the *bbox* argument. .. figure:: ../../gallery/userdemo/images/sphx_glr_annotate_simple03_001.png :target: ../../gallery/userdemo/annotate_simple03.html :align: center By default, the starting point is set to the center of the text extent. This can be adjusted with ``relpos`` key value. The values are normalized to the extent of the text. For example, (0, 0) means lower-left corner and (1, 1) means top-right. .. figure:: ../../gallery/userdemo/images/sphx_glr_annotate_simple04_001.png :target: ../../gallery/userdemo/annotate_simple04.html :align: center Placing Artist at anchored Axes locations ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ There are classes of artists that can be placed at an anchored location in the Axes. A common example is the legend. This type of artist can be created by using the `.OffsetBox` class. A few predefined classes are available in :mod:`matplotlib.offsetbox` and in :mod:`mpl_toolkits.axes_grid1.anchored_artists`. .. GENERATED FROM PYTHON SOURCE LINES 291-300 .. code-block:: default from matplotlib.offsetbox import AnchoredText fig, ax = plt.subplots() at = AnchoredText( "Figure 1a", prop=dict(size=15), frameon=True, loc='upper left') at.patch.set_boxstyle("round,pad=0.,rounding_size=0.2") ax.add_artist(at) .. image-sg:: /tutorials/text/images/sphx_glr_annotations_001.png :alt: annotations :srcset: /tutorials/text/images/sphx_glr_annotations_001.png, /tutorials/text/images/sphx_glr_annotations_001_2_0x.png 2.0x :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out .. code-block:: none .. GENERATED FROM PYTHON SOURCE LINES 301-317 The *loc* keyword has same meaning as in the legend command. A simple application is when the size of the artist (or collection of artists) is known in pixel size during the time of creation. For example, If you want to draw a circle with fixed size of 20 pixel x 20 pixel (radius = 10 pixel), you can utilize `~mpl_toolkits.axes_grid1.anchored_artists.AnchoredDrawingArea`. The instance is created with a size of the drawing area (in pixels), and arbitrary artists can added to the drawing area. Note that the extents of the artists that are added to the drawing area are not related to the placement of the drawing area itself. Only the initial size matters. The artists that are added to the drawing area should not have a transform set (it will be overridden) and the dimensions of those artists are interpreted as a pixel coordinate, i.e., the radius of the circles in above example are 10 pixels and 5 pixels, respectively. .. GENERATED FROM PYTHON SOURCE LINES 317-330 .. code-block:: default from matplotlib.patches import Circle from mpl_toolkits.axes_grid1.anchored_artists import AnchoredDrawingArea fig, ax = plt.subplots() ada = AnchoredDrawingArea(40, 20, 0, 0, loc='upper right', pad=0., frameon=False) p1 = Circle((10, 10), 10) ada.drawing_area.add_artist(p1) p2 = Circle((30, 10), 5, fc="r") ada.drawing_area.add_artist(p2) ax.add_artist(ada) .. image-sg:: /tutorials/text/images/sphx_glr_annotations_002.png :alt: annotations :srcset: /tutorials/text/images/sphx_glr_annotations_002.png, /tutorials/text/images/sphx_glr_annotations_002_2_0x.png 2.0x :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out .. code-block:: none .. GENERATED FROM PYTHON SOURCE LINES 331-342 Sometimes, you want your artists to scale with the data coordinate (or coordinates other than canvas pixels). You can use `~mpl_toolkits.axes_grid1.anchored_artists.AnchoredAuxTransformBox` class. This is similar to `~mpl_toolkits.axes_grid1.anchored_artists.AnchoredDrawingArea` except that the extent of the artist is determined during the drawing time respecting the specified transform. The ellipse in the example below will have width and height corresponding to 0.1 and 0.4 in data coordinates and will be automatically scaled when the view limits of the axes change. .. GENERATED FROM PYTHON SOURCE LINES 342-352 .. code-block:: default from matplotlib.patches import Ellipse from mpl_toolkits.axes_grid1.anchored_artists import AnchoredAuxTransformBox fig, ax = plt.subplots() box = AnchoredAuxTransformBox(ax.transData, loc='upper left') el = Ellipse((0, 0), width=0.1, height=0.4, angle=30) # in data coordinates! box.drawing_area.add_artist(el) ax.add_artist(box) .. image-sg:: /tutorials/text/images/sphx_glr_annotations_003.png :alt: annotations :srcset: /tutorials/text/images/sphx_glr_annotations_003.png, /tutorials/text/images/sphx_glr_annotations_003_2_0x.png 2.0x :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out .. code-block:: none .. GENERATED FROM PYTHON SOURCE LINES 353-509 As in the legend, the bbox_to_anchor argument can be set. Using the HPacker and VPacker, you can have an arrangement(?) of artist as in the legend (as a matter of fact, this is how the legend is created). .. figure:: ../../gallery/userdemo/images/sphx_glr_anchored_box04_001.png :target: ../../gallery/userdemo/anchored_box04.html :align: center Note that unlike the legend, the ``bbox_transform`` is set to IdentityTransform by default. Coordinate systems for Annotations ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Matplotlib Annotations support several types of coordinates. Some are described in :ref:`annotations-tutorial`; more advanced options are 1. A `.Transform` instance. For example, :: ax.annotate("Test", xy=(0.5, 0.5), xycoords=ax.transAxes) is identical to :: ax.annotate("Test", xy=(0.5, 0.5), xycoords="axes fraction") This allows annotating a point in another axes:: fig, (ax1, ax2) = plt.subplots(1, 2) ax2.annotate("Test", xy=(0.5, 0.5), xycoords=ax1.transData, xytext=(0.5, 0.5), textcoords=ax2.transData, arrowprops=dict(arrowstyle="->")) 2. An `.Artist` instance. The *xy* value (or *xytext*) is interpreted as a fractional coordinate of the bbox (return value of *get_window_extent*) of the artist:: an1 = ax.annotate("Test 1", xy=(0.5, 0.5), xycoords="data", va="center", ha="center", bbox=dict(boxstyle="round", fc="w")) an2 = ax.annotate("Test 2", xy=(1, 0.5), xycoords=an1, # (1, 0.5) of the an1's bbox xytext=(30, 0), textcoords="offset points", va="center", ha="left", bbox=dict(boxstyle="round", fc="w"), arrowprops=dict(arrowstyle="->")) .. figure:: ../../gallery/userdemo/images/sphx_glr_annotate_simple_coord01_001.png :target: ../../gallery/userdemo/annotate_simple_coord01.html :align: center Note that you must ensure that the extent of the coordinate artist (*an1* in above example) is determined before *an2* gets drawn. Usually, this means that *an2* needs to be drawn after *an1*. 3. A callable object that takes the renderer instance as single argument, and returns either a `.Transform` or a `.BboxBase`. The return value is then handled as in (1), for transforms, or in (2), for bboxes. For example, :: an2 = ax.annotate("Test 2", xy=(1, 0.5), xycoords=an1, xytext=(30, 0), textcoords="offset points") is identical to:: an2 = ax.annotate("Test 2", xy=(1, 0.5), xycoords=an1.get_window_extent, xytext=(30, 0), textcoords="offset points") 4. A pair of coordinate specifications -- the first for the x-coordinate, and the second is for the y-coordinate; e.g. :: annotate("Test", xy=(0.5, 1), xycoords=("data", "axes fraction")) Here, 0.5 is in data coordinates, and 1 is in normalized axes coordinates. Each of the coordinate specifications can also be an artist or a transform. For example, .. figure:: ../../gallery/userdemo/images/sphx_glr_annotate_simple_coord02_001.png :target: ../../gallery/userdemo/annotate_simple_coord02.html :align: center 5. Sometimes, you want your annotation with some "offset points", not from the annotated point but from some other point. `.text.OffsetFrom` is a helper for such cases. .. figure:: ../../gallery/userdemo/images/sphx_glr_annotate_simple_coord03_001.png :target: ../../gallery/userdemo/annotate_simple_coord03.html :align: center You may take a look at this example :doc:`/gallery/text_labels_and_annotations/annotation_demo`. Using ConnectionPatch ~~~~~~~~~~~~~~~~~~~~~ `.ConnectionPatch` is like an annotation without text. While `~.Axes.annotate` is sufficient in most situations, `.ConnectionPatch` is useful when you want to connect points in different axes. :: from matplotlib.patches import ConnectionPatch xy = (0.2, 0.2) con = ConnectionPatch(xyA=xy, coordsA=ax1.transData, xyB=xy, coordsB=ax2.transData) fig.add_artist(con) The above code connects point *xy* in the data coordinates of ``ax1`` to point *xy* in the data coordinates of ``ax2``. Here is a simple example. .. figure:: ../../gallery/userdemo/images/sphx_glr_connect_simple01_001.png :target: ../../gallery/userdemo/connect_simple01.html :align: center Here, we added the `.ConnectionPatch` to the *figure* (with `~.Figure.add_artist`) rather than to either axes: this ensures that it is drawn on top of both axes, and is also necessary if using :doc:`constrained_layout ` for positioning the axes. Advanced Topics --------------- Zoom effect between Axes ~~~~~~~~~~~~~~~~~~~~~~~~ `mpl_toolkits.axes_grid1.inset_locator` defines some patch classes useful for interconnecting two axes. Understanding the code requires some knowledge of Matplotlib's transform system. .. figure:: ../../gallery/subplots_axes_and_figures/images/sphx_glr_axes_zoom_effect_001.png :target: ../../gallery/subplots_axes_and_figures/axes_zoom_effect.html :align: center Define Custom BoxStyle ~~~~~~~~~~~~~~~~~~~~~~ You can use a custom box style. The value for the ``boxstyle`` can be a callable object in the following forms.:: def __call__(self, x0, y0, width, height, mutation_size, aspect_ratio=1.): ''' Given the location and size of the box, return the path of the box around it. - *x0*, *y0*, *width*, *height* : location and size of the box - *mutation_size* : a reference scale for the mutation. - *aspect_ratio* : aspect-ratio for the mutation. ''' path = ... return path Here is a complete example. .. figure:: ../../gallery/userdemo/images/sphx_glr_custom_boxstyle01_001.png :target: ../../gallery/userdemo/custom_boxstyle01.html :align: center Similarly, you can define a custom ConnectionStyle and a custom ArrowStyle. See the source code of ``lib/matplotlib/patches.py`` and check how each style class is defined. .. _sphx_glr_download_tutorials_text_annotations.py: .. only:: html .. container:: sphx-glr-footer sphx-glr-footer-example .. container:: sphx-glr-download sphx-glr-download-python :download:`Download Python source code: annotations.py ` .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: annotations.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_