high_contrast.module in High contrast 8

Allows users to switch to a high contrast version of the active theme.

File

high_contrast.module

<?php

/**
 * @file
 * Allows users to switch to a high contrast version of the active theme.
 */
use Drupal\Core\Block\BlockPluginInterface;
use Drupal\high_contrast\HighContrastTrait;

/**
 * Location of the high_contrast.css folder.
 */
const HIGH_CONTRAST_CSS_FOLDER = 'public://css/';

/**
 * Location of the high_contrast.css file.
 */
const HIGH_CONTRAST_CSS_LOCATION = 'public://css/high_contrast.css';

/**
 * Implements hook_library_info_build().
 */
function high_contrast_library_info_build() {
  $libraries = [];
  $libraries['high_contrast'] = [
    'version' => filemtime(HIGH_CONTRAST_CSS_LOCATION),
    'css' => [
      'base' => [
        HIGH_CONTRAST_CSS_LOCATION => [],
      ],
    ],
  ];
  return $libraries;
}

/**
 * Implements hook_page_attachments().
 *
 * Attach the library to the page instead of attaching it to the form, so the
 * high contrast persists even on pages where the HighContrastSwitchForm is not
 * being displayed.
 */
function high_contrast_page_attachments(array &$attachments) {
  $attachments['#cache']['contexts'][] = 'high_contrast';
  $attachments['#cache']['tags'][] = 'config:high_contrast.settings';
  if (HighContrastTrait::highContrastEnabled()) {
    $attachments['#attached']['library'][] = 'high_contrast/high_contrast';
  }
}

/**
 * Implements hook_block_view_alter().
 */
function high_contrast_block_view_alter(array &$build, BlockPluginInterface $block) {
  $build['#pre_render'][] = '\\Drupal\\high_contrast\\HighContrastBlockView::preRender';
}

/**
 * Function for building a custom high contrast stylesheet.
 *
 * @param string $background
 *   The hex color value to use as background.
 * @param string $text
 *   The hex color value to use for texts.
 * @param string $hyperlink
 *   The hex color value to use for hyperlinks.
 *
 * @return string
 *   The compiled CSS.
 */
function _high_contrast_build_css($background, $text, $hyperlink) {
  $css = '
* {
  background-color: ' . $background . ' !important;
  background-image: none !important;
  color: ' . $text . ' !important;
  line-height: 1.5em !important;
  text-shadow: none !important;
}

a, a * {
  background-color: ' . $background . ' !important;
  color: ' . $hyperlink . ' !important;
  text-decoration: underline !important;
}

a:hover, a:hover * {
  background-color: ' . $hyperlink . ' !important;
  color: ' . $background . ' !important;
  text-decoration: none !important;
}

input {
  background-color: ' . $text . ' !important;
  color: ' . $background . ' !important;
}

input[type=submit],
input[type=button],
button {
  background-color: ' . $hyperlink . ' !important;
  color: ' . $background . ' !important;
}

input[type=submit]:hover,
input[type=button]:hover,
button:hover {
  text-decoration: underline !important;
}

::selection {
  background-color: cyan !important;
  color: ' . $background . ' !important;
}
';
  return $css;
}

Functions

Name	Description
high_contrast_block_view_alter	Implements hook_block_view_alter().
high_contrast_library_info_build	Implements hook_library_info_build().
high_contrast_page_attachments	Implements hook_page_attachments().
_high_contrast_build_css	Function for building a custom high contrast stylesheet.

Constants

Name	Description
HIGH_CONTRAST_CSS_FOLDER	Location of the high_contrast.css folder.
HIGH_CONTRAST_CSS_LOCATION	Location of the high_contrast.css file.