.. _content-api:

API reference

The API reference documentation describes the library interfaces, e.g. inputs, outputs,

and expected behavior. See :ref:`writing-docstrings` for guidance on writing docstrings.

The pages in :file:`doc/api` are purely technical definitions of layout; therefore new

API reference documentation should be added to the module docstrings. This placement

keeps all API reference documentation about a module in the same file.

.. _content-examples:

Examples gallery

The gallery of examples contains visual demonstrations of Matplotlib features. Gallery

examples exist so that readers can scan through visual examples. Unlike tutorials or

user guides, gallery examples teach by demonstration, rather than by instruction or

explanation.

Gallery examples should avoid instruction or excessive explanation except for brief

clarifying code comments. Instead, they can tag related concepts and/or link to relevant

tutorials or user guides.

Format

All :ref:`examples-index` should aim to follow the following format:

* Title: 1-6 words, descriptive of content

* Subtitle: 10-50 words, action-oriented description of the example subject

* Image: a clear demonstration of the subject, showing edge cases and different

applications if possible

* Code + Text (optional): code, commented as appropriate + written text to add context

if necessary

Example:

The ``bbox_intersect`` gallery example demonstrates the point of visual examples:

* this example is "messy" in that it's hard to categorize, but the gallery is the right

spot for it because it makes sense to find it by visual search

* :doc:`../gallery/misc/bbox_intersect`

.. _documenting-content:

Documentation content guide

These guidelines aim to improve the consistency, cohesiveness, and organization of the

:ref: documentation concerning using the library by broadly articulating the intended purpose,

scope, and audience of each of the following sections:

:ref:`plot_types`

| Summary of chart types that are implemented as high-level API

:ref:`User guide <users-guide-index>`

| Explanations of features, components, and architecture.

:ref:`tutorials`

| Lessons on developing visualizations

:ref:`examples-index`

| Demonstrations of specific library features

:ref:`api-reference`

| Descriptions of the public modules, objects, methods, and functions.

.. note::

While parts of the current documentation may not yet align with these guidelines,

we expect that new documentation contributions will also bring existing documentation

into alignment.

Audience

The Matplotlib audience encompasses a wide spectrum of readers, from users who are first

getting introduced to using Matplotlib through the documentation to experienced developers

who want to make something extremely customized. Instead of trying to write for the

entire spectrum, each document should identify its band so that reader can assess

whether the document is appropriate for them. The documentation should generally use the

leveling of :doc:`tags <tag_glossary>` and :ref:`issues <new_contributors>`, meaning

that the audienced is identified based on how much contextual understanding of

Matplotlib is a pre-requisite for following along with the document.

Documents can communicate this leveling through :doc:`tags <tag_guidelines>`, their

location in the docs, and in text as appropriate. For example:

This guide assumes that the reader understands the general concept of Artists, as

explained in :doc:`../users/explain/artists/artist_intro`

Scope

Many concepts in Matplotlib assume a grounding in visualization, statistics, Python

programming, and other topics to understand how they work. These concepts should be

contextualized using common terminology, but the focus for all documents should not

stray from the Matplotlib topic. For example:

Some of the path components require multiple vertices to specify them: for example

CURVE 3 is a `Bézier curve <https://en.wikipedia.org/wiki/B%C3%A9zier_curve>`_ with

one control point and one end point, and CURVE4 has three vertices for the two

control points and the end point. The example below shows a CURVE4 Bézier spline --

the Bézier curve will be contained in the convex hull of the start point, the two

control points, and the end point

This explanation of drawing a curve using control points from :ref:`paths` never

explicitly defines a *Bézier curve*, instead linking out to an external

reference. This explanation is written in a manner where the definition of

*Bézier curve* can be inferred from context and also understanding is not harmed if the

reader does not infer the definition.

Guidelines

This content guide is heavily influenced by the `Diátaxis <https://diataxis.fr/>`_

framework for technical documentation; this framework proposes that all technical

documentation is roughly one of 4 types - tutorials, how-to-guides,

technical reference, and explanation - and that the appropriate type is determined

by whether *what* is x? (cognition) vs *how* to do x?(action) is being documented, and

whether the document's purpose is *acquiring* (learning) or *applying* (using) skills.

Broadly, our documentation as viewed through a diátaxis lens:

.. list-table::

:header-rows: 1

:widths: 20 30 20 30

* - section

- goal

- type

- example

* - :ref:`plot_types`

- View available chart types.

- | `Reference <https://diataxis.fr/reference/>`_

| what, use

- :ref:`sphx_glr_plot_types_stats_pie.py`

* - :ref:`User guide <users-guide-index>`

- Understand features, components, and architecture

- | `Explanation <https://diataxis.fr/explanation/>`_

| what, learn

- :ref:`annotations`

* - :ref:`tutorials`

- Work through the stages of building a visualization.

- | `Tutorials <https://diataxis.fr/tutorials/>`_

| how, learn

- :ref:`pie_donut_labels`

* - :ref:`examples-index`

- Execute a visualization task.

- | `How-to guides <https://diataxis.fr/how-to-guides/>`_

| how, use

- :ref:`sphx_glr_gallery_text_labels_and_annotations_rainbow_text.py`

* - :ref:`api-reference`

- Look up the input/output/behavior of public API.

- | `Reference <https://diataxis.fr/reference/>`_

| what, use

- `.Axes.annotate`

Detailed guidelines for each section are documented at their respective pages:

.. toctree::

plot_types

user_guide

tutorials

examples

api

.. _content-plot-types:

Plot types gallery

The plot type gallery displays a selection of the common visualization techniques that

are implemented in Matplotlib. The gallery is heavily curated and tightly scoped to the

plotting methods on `matplotlib.axes.Axes` so additions are generally discouraged.

Format

* very short: 5-10 lines

* self explanatory data

* little to no customization.

.. _content-tutorials:

Tutorials

The goal of the tutorials is to guide the reader through the stages of using Matplotlib

to build specific visualization. The tutorials focus on learning how to combine the

features and components that were explained in the user guide.

Format

As with the user guide, the tutorials should aim to unpack information in chunks and

build on the previous section.

Where the user guide explains topics like plotting and animation separately, a tutorial

walks the reader through the steps involved in animating a line plot. Generally the

content is limited to describing what is happening at each stage- for example there's no

explanation of why an update function is written-and instead the reader is linked to an

explanation.

#. First we start by stating the objective:

.. code-block:: rst

#. Then we describe what needs to be in place to do the task. Here that is the data and

object that we will animate:

.. code-block:: rst

#. With our pieces in place, we instruct the reader on how to animate the object:

.. code-block:: rst

#. Next we show them how to generate the animation and describe the arguments:

.. code-block:: rst

#. Then we put all the steps together to make the animated sin wave:

.. code-block:: rst

#. Finally, we close with a follow up call to action to learn about the underlying

concepts:

.. code-block:: rst

Please note that while the aim is to show how to animate a sin curve, the focus is

always on making the animation. Generally explanations of domain should be limited to

providing contextually necessary information, and tutorials that are heavily domain

specific may be more appropriate for the Scientific Python

`blog <https://blog.scientific-python.org/>`_.