MarkdownViewer

Added in version 0.11.0

A Widget to display Markdown content with an optional Table of Contents.

• Focusable
• Container

Note

This Widget adds browser-like functionality on top of the Markdown widget.

Example

The following example displays Markdown from a string and a Table of Contents.

Outputmarkdown.py

from textual.app import App, ComposeResult
from textual.widgets import MarkdownViewer

EXAMPLE_MARKDOWN = """\
# Markdown Viewer

This is an example of Textual's `MarkdownViewer` widget.


## Features

Markdown syntax and extensions are supported.

- Typography *emphasis*, **strong**, `inline code` etc.
- Headers
- Lists (bullet and ordered)
- Syntax highlighted code blocks
- Tables!

## Tables

Tables are displayed in a DataTable widget.

| Name            | Type   | Default | Description                        |
| --------------- | ------ | ------- | ---------------------------------- |
| `show_header`   | `bool` | `True`  | Show the table header              |
| `fixed_rows`    | `int`  | `0`     | Number of fixed rows               |
| `fixed_columns` | `int`  | `0`     | Number of fixed columns            |
| `zebra_stripes` | `bool` | `False` | Display alternating colors on rows |
| `header_height` | `int`  | `1`     | Height of header row               |
| `show_cursor`   | `bool` | `True`  | Show a cell cursor                 |


## Code Blocks

Code blocks are syntax highlighted, with guidelines.

```python
class ListViewExample(App):
    def compose(self) -> ComposeResult:
        yield ListView(
            ListItem(Label("One")),
            ListItem(Label("Two")),
            ListItem(Label("Three")),
        )
        yield Footer()
```
"""


class MarkdownExampleApp(App):
    def compose(self) -> ComposeResult:
        yield MarkdownViewer(EXAMPLE_MARKDOWN, show_table_of_contents=True)


if __name__ == "__main__":
    app = MarkdownExampleApp()
    app.run()

Reactive Attributes

Name	Type	Default	Description
show_table_of_contents	bool	True	Wether a Table of Contents should be displayed with the Markdown.

Messages

This widget posts no messages.

Bindings

This widget has no bindings.

Component Classes

This widget has no component classes.

See Also

• Markdown code reference

---

Bases: VerticalScroll

A Markdown viewer widget.

Parameters:

Name	Type	Description	Default
markdown	str | None	String containing Markdown, or None to leave blank.	None
show_table_of_contents	bool	Show a table of contents in a sidebar.	True
name	str | None	The name of the widget.	None
id	str | None	The ID of the widget in the DOM.	None
classes	str | None	The CSS classes of the widget.	None
parser_factory	Callable[[], MarkdownIt] | None	A factory function to return a configured MarkdownIt instance. If None, a "gfm-like" parser is used.	None

document property

document

The Markdown document widget.

table_of_contents property

table_of_contents

The table of contents widget.

NavigatorUpdated

NavigatorUpdated()

Bases: Message

Navigator has been changed (clicked link etc).

back async

back()

Go back one level in the history.

forward async

forward()

Go forward one level in the history.

go async

go(location)

Navigate to a new document path.

textual.widgets.markdown

TableOfContentsType module-attribute

TableOfContentsType = 'list[tuple[int, str, str | None]]'

Information about the table of contents of a markdown document.

The triples encode the level, the label, and the optional block id of each heading.

Markdown

Markdown(
    markdown=None,
    *,
    name=None,
    id=None,
    classes=None,
    parser_factory=None
)

Bases: Widget

Parameters:

Name	Type	Description	Default
markdown	str | None	String containing Markdown or None to leave blank for now.	None
name	str | None	The name of the widget.	None
id	str | None	The ID of the widget in the DOM.	None
classes	str | None	The CSS classes of the widget.	None
parser_factory	Callable[[], MarkdownIt] | None	A factory function to return a configured MarkdownIt instance. If None, a "gfm-like" parser is used.	None

COMPONENT_CLASSES class-attribute instance-attribute

COMPONENT_CLASSES = {'em', 'strong', 's', 'code_inline'}

These component classes target standard inline markdown styles. Changing these will potentially break the standard markdown formatting.

Class	Description
code_inline	Target text that is styled as inline code.
em	Target text that is emphasized inline.
s	Target text that is styled inline with strykethrough.
strong	Target text that is styled inline with strong.

code_dark_theme class-attribute instance-attribute

code_dark_theme = reactive('material')

The theme to use for code blocks when in dark mode.

code_light_theme class-attribute instance-attribute

code_light_theme = reactive('material-light')

The theme to use for code blocks when in light mode.

LinkClicked

LinkClicked(markdown, href)

Bases: Message

A link in the document was clicked.

control property

control

The Markdown widget containing the link clicked.

This is an alias for LinkClicked.markdown and is used by the on decorator.

href instance-attribute

href = unquote(href)

The link that was selected.

markdown instance-attribute

markdown = markdown

The Markdown widget containing the link clicked.

TableOfContentsSelected

TableOfContentsSelected(markdown, block_id)

Bases: Message

An item in the TOC was selected.

block_id instance-attribute

block_id = block_id

ID of the block that was selected.

control property

control

The Markdown widget where the selected item is.

This is an alias for TableOfContentsSelected.markdown and is used by the on decorator.

markdown instance-attribute

markdown = markdown

The Markdown widget where the selected item is.

TableOfContentsUpdated

TableOfContentsUpdated(markdown, table_of_contents)

Bases: Message

The table of contents was updated.

control property

control

The Markdown widget associated with the table of contents.

This is an alias for TableOfContentsUpdated.markdown and is used by the on decorator.

markdown instance-attribute

markdown = markdown

The Markdown widget associated with the table of contents.

table_of_contents instance-attribute

table_of_contents = table_of_contents

Table of contents.

goto_anchor

goto_anchor(anchor)

Try and find the given anchor in the current document.

Parameters:

Name	Type	Description	Default
anchor	str	The anchor to try and find.	required

Note

The anchor is found by looking at all of the headings in the document and finding the first one whose slug matches the anchor.

Note that the slugging method used is similar to that found on GitHub.

Returns:

Type	Description
bool	True when the anchor was found in the current document, False otherwise.

load async

load(path)

Load a new Markdown document.

Parameters:

Name	Type	Description	Default
path	Path	Path to the document.	required

Raises:

Type	Description
OSError	If there was some form of error loading the document.

Note

The exceptions that can be raised by this method are all of those that can be raised by calling Path.read_text.

sanitize_location staticmethod

sanitize_location(location)

Given a location, break out the path and any anchor.

Parameters:

Name	Type	Description	Default
location	str	The location to sanitize.	required

Returns:

Type	Description
Path	A tuple of the path to the location cleaned of any anchor, plus
str	the anchor (or an empty string if none was found).

unhandled_token

unhandled_token(token)

Process an unhandled token.

Parameters:

Name	Type	Description	Default
token	Token	The MarkdownIt token to handle.	required

Returns:

Type	Description
MarkdownBlock | None	Either a widget to be added to the output, or None.

update

update(markdown)

Update the document with new Markdown.

Parameters:

Name	Type	Description	Default
markdown	str	A string containing Markdown.	required

Returns:

Type	Description
AwaitComplete	An optionally awaitable object. Await this to ensure that all children have been mounted.

MarkdownBlock

MarkdownBlock(markdown, *args, **kwargs)

Bases: Static

The base class for a Markdown Element.

action_link async

action_link(href)

Called on link click.

build_from_token

build_from_token(token)

Build the block content from its source token.

This method allows the block to be rebuilt on demand, which is useful when the styles assigned to the Markdown.COMPONENT_CLASSES change.

See https://github.com/Textualize/textual/issues/3464 for more information.

Parameters:

Name	Type	Description	Default
token	Token	The token from which this block is built.	required

notify_style_update

notify_style_update()

If CSS was reloaded, try to rebuild this block from its token.

rebuild

rebuild()

Rebuild the content of the block if we have a source token.

MarkdownTableOfContents

MarkdownTableOfContents(
    markdown,
    name=None,
    id=None,
    classes=None,
    disabled=False,
)

Bases: Widget

Displays a table of contents for a markdown document.

Parameters:

Name	Type	Description	Default
markdown	Markdown	The Markdown document associated with this table of contents.	required
name	str | None	The name of the widget.	None
id	str | None	The ID of the widget in the DOM.	None
classes	str | None	The CSS classes for the widget.	None
disabled	bool	Whether the widget is disabled or not.	False

markdown instance-attribute

markdown = markdown

The Markdown document associated with this table of contents.

table_of_contents class-attribute instance-attribute

table_of_contents = reactive[Optional[TableOfContentsType]](
    None, init=False
)

Underlying data to populate the table of contents widget.

rebuild_table_of_contents

rebuild_table_of_contents(table_of_contents)

Rebuilds the tree representation of the table of contents data.

Parameters:

Name	Type	Description	Default
table_of_contents	TableOfContentsType	Table of contents.	required

watch_table_of_contents

watch_table_of_contents(table_of_contents)

Triggered when the table of contents changes.