Use mytheme_preprocess_block() to display HTML (icon fonts) in block titles

Question

Unfortunately, HTML commands in block titles are not being rendered. I would like to be able to add icon font symbols to my block titles by adding comands like <i class="icon-envelope"></i> (this is Font Awesome syntax) to them WITHOUT installing yet another contrib module.

Is there a way to let HTML in block titles being rendered by adding a mytheme_preprocess_block() function to my template.php?

I came across a solution to let HTML commands in menu links being rendered by adding

function mytheme_link($variables) {
    $variables['options']['html'] = TRUE;
    return '' . ($variables['options']['html'] ? $variables['text'] : check_plain($variables['text'])) . '';
}

to my template.php but haven't managed to modify the code for block titles.

Answer 1

In preprocess_block() function you can only define the title prefix and suffix for each title.

For example:

/**
 * Override or insert variables into the block template.
 */
function YOURTHEME_preprocess_block(&$variables) {

  $variables['title_prefix'] = array(
    '#type' => 'markup',
    '#markup' => '<i class="icon-envelope">',
  );
  $variables['title_suffix'] = array(
    '#type' => 'markup',
    '#markup' => '</i>',
  );

}

Answer 2

In some themes, such as Zen, The block title gets turned into the block "subject" (a variable that is ran through Drupal check_plain() function) in the process function. You want to override the process function, and NOT the preprocess function.

function mytheme_process_block(&$variables, $hook) {
  $block = $variables['block'];
  if (isset($block->title) && strlen($block->title) > 0) {
    $variables['title'] = $block->title;
  }
}