This is the documentation for the unsupported version 0.18. Please consider upgrading your code to the latest stable version

Block Rendering

Block renderers are responsible for converting the parsed AST elements into their HTML representation.

All block renderers should implement BlockRendererInterface and its render() method:


The HtmlRenderer will call this method whenever a supported block element is encountered in the AST being rendered.

If the method can only handle certain block types, be sure to verify that you’ve been passed the correct type.


Return value

The method must return the final HTML representation of the block and any of its contents. This can be an HtmlElement object (preferred; castable to a string) or a string of raw HTML.

You are responsible for handling any escaping that may be necessary.

Designating Block Renderers

When registering your render, you must tell the Environment which block element class your renderer should handle. For example:


$environment = Environment::createCommonMarkEnvironment();

// First param - the block class type that should use our renderer
// Second param - instance of the block renderer
$environment->addBlockRenderer('League\CommonMark\Block\Element\FencedCode', new MyCustomCodeRenderer());

A single renderer could even be used for multiple block types:


$environment = Environment::createCommonMarkEnvironment();

$myRenderer = new MyCustomCodeRenderer();

$environment->addBlockRenderer('League\CommonMark\Block\Element\FencedCode', $myRenderer);
$environment->addBlockRenderer('League\CommonMark\Block\Element\IndentedCode', $myRenderer);

Only one renderer can be assigned per element type. If multiple renderers are assigned to the same block class, only the last one will be used.


Here’s a custom renderer which renders thematic breaks as text (instead of <hr>):


class TextDividerRenderer implements BlockRendererInterface
    public function render(AbstractBlock $block, ElementRendererInterface $htmlRenderer, $inTightList = false)
        return new HtmlElement('pre', ['class' => 'divider'], '==============================');

$environment = Environment::createCommonMarkEnvironment();
$environment->addBlockRenderer('League\CommonMark\Block\Element\ThematicBreak', new TextDividerRenderer());