@instructure/canvas-rce
Version:
A component wrapping Canvas's usage of Tinymce
47 lines (46 loc) • 2.01 kB
JavaScript
/*
* Copyright (C) 2018 - present Instructure, Inc.
*
* This file is part of Canvas.
*
* Canvas is free software: you can redistribute it and/or modify it under
* the terms of the GNU Affero General Public License as published by the Free
* Software Foundation, version 3 of the License.
*
* Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
* A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
* details.
*
* You should have received a copy of the GNU Affero General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*/
import formatMessage from '../../../../format-message';
import contrast from 'wcag-element-contrast';
import smallTextContrast from './small-text-contrast';
import { onlyContainsLink, hasTextNode } from '../utils/dom';
export default {
id: 'large-text-contrast',
test: (elem, config = {}) => {
const disabled = config.disableContrastCheck == true;
const noText = !hasTextNode(elem);
if (disabled || noText || onlyContainsLink(elem) || !contrast.isLargeText(elem)) {
return true;
}
for (let e = elem; e; e = e.parentElement) {
const bgimage = window.getComputedStyle(e).getPropertyValue('background-image');
if (bgimage !== 'none' && bgimage !== '') {
// ignore background images and gradients
return true;
}
}
return contrast(elem);
},
data: smallTextContrast.data,
form: smallTextContrast.form,
update: smallTextContrast.update,
message: () => formatMessage('Text larger than 18pt (or bold 14pt) should display a minimum contrast ratio of 3:1.'),
why: () => formatMessage('Text is difficult to read without sufficient contrast between the text and the background, especially for those with low vision.'),
link: 'https://www.w3.org/TR/WCAG20-TECHS/G17.html',
linkText: () => formatMessage('Learn more about color contrast')
};