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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.

MarkdownExampleApp ▼ Ⅰ Markdown Viewer ├── Ⅱ FeaturesMarkdown Viewer ├── Ⅱ Tables └── Ⅱ Code BlocksThis 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_headerboolTrueShow the table header                  fixed_rowsint0Number of fixed rows                   fixed_columnsint0Number of fixed columns                zebra_stripesboolFalseDisplay alternating colors on rows     header_heightint1Height of header row                   show_cursorboolTrueShow a cell cursor                     Code Blocks ▅▅ Code blocks are syntax highlighted, with guidelines. classListViewExample(App): │   defcompose(self)->ComposeResult: │   │   yieldListView( 

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

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

open_links

bool

Open links automatically. If you set this to False, you can handle the LinkClicked events.

 True

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,
    open_links=True
)

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

open_links

bool

Open links automatically. If you set this to False, you can handle the LinkClicked events.

 True

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 strikethrough.
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 the App theme is dark.

code_light_theme class-attribute instance-attribute 

code_light_theme = reactive('material-light')

The theme to use for code blocks when the App theme is light.

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(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.