/*----------------------------------------
* objectFitPolyfill 2.3.5
*
* Made by Constance Chen
* Released under the ISC license
*
* https://github.com/constancecchen/object-fit-polyfill
*--------------------------------------*/
(function() {
'use strict';
// if the page is being rendered on the server, don't continue
if (typeof window === 'undefined') return;
// Workaround for Edge 16-18, which only implemented object-fit for <img> tags
var edgeMatch = window.navigator.userAgent.match(/Edge\/(\d{2})\./);
var edgeVersion = edgeMatch ? parseInt(edgeMatch[1], 10) : null;
var edgePartialSupport = edgeVersion
? edgeVersion >= 16 && edgeVersion <= 18
: false;
// If the browser does support object-fit, we don't need to continue
var hasSupport = 'objectFit' in document.documentElement.style !== false;
if (hasSupport && !edgePartialSupport) {
window.objectFitPolyfill = function() {
return false;
};
return;
}
/**
* Check the container's parent element to make sure it will
* correctly handle and clip absolutely positioned children
*
* @param {node} $container - parent element
*/
var checkParentContainer = function($container) {
var styles = window.getComputedStyle($container, null);
var position = styles.getPropertyValue('position');
var overflow = styles.getPropertyValue('overflow');
var display = styles.getPropertyValue('display');
if (!position || position === 'static') {
$container.style.position = 'relative';
}
if (overflow !== 'hidden') {
$container.style.overflow = 'hidden';
}
// Guesstimating that people want the parent to act like full width/height wrapper here.
// Mostly attempts to target <picture> elements, which default to inline.
if (!display || display === 'inline') {
$container.style.display = 'block';
}
if ($container.clientHeight === 0) {
$container.style.height = '100%';
}
// Add a CSS class hook, in case people need to override styles for any reason.
if ($container.className.indexOf('object-fit-polyfill') === -1) {
$container.className = $container.className + ' object-fit-polyfill';
}
};
/**
* Check for pre-set max-width/height, min-width/height,
* positioning, or margins, which can mess up image calculations
*
* @param {node} $media - img/video element
*/
var checkMediaProperties = function($media) {
var styles = window.getComputedStyle($media, null);
var constraints = {
'max-width': 'none',
'max-height': 'none',
'min-width': '0px',
'min-height': '0px',
top: 'auto',
right: 'auto',
bottom: 'auto',
left: 'auto',
'margin-top': '0px',
'margin-right': '0px',
'margin-bottom': '0px',
'margin-left': '0px',
};
for (var property in constraints) {
var constraint = styles.getPropertyValue(property);
if (constraint !== constraints[property]) {
$media.style[property] = constraints[property];
}
}
};
/**
* Calculate & set object-position
*
* @param {string} axis - either "x" or "y"
* @param {node} $media - img or video element
* @param {string} objectPosition - e.g. "50% 50%", "top left"
*/
var setPosition = function(axis, $media, objectPosition) {
var position, other, start, end, side;
objectPosition = objectPosition.split(' ');
if (objectPosition.length < 2) {
objectPosition[1] = objectPosition[0];
}
/* istanbul ignore else */
if (axis === 'x') {
position = objectPosition[0];
other = objectPosition[1];
start = 'left';
end = 'right';
side = $media.clientWidth;
} else if (axis === 'y') {
position = objectPosition[1];
other = objectPosition[0];
start = 'top';
end = 'bottom';
side = $media.clientHeight;
} else {
return; // Neither x or y axis specified
}
if (position === start || other === start) {
$media.style[start] = '0';
return;
}
if (position === end || other === end) {
$media.style[end] = '0';
return;
}
if (position === 'center' || position === '50%') {
$media.style[start] = '50%';
$media.style['margin-' + start] = side / -2 + 'px';
return;
}
// Percentage values (e.g., 30% 10%)
if (position.indexOf('%') >= 0) {
position = parseInt(position, 10);
if (position < 50) {
$media.style[start] = position + '%';
$media.style['margin-' + start] = side * (position / -100) + 'px';
} else {
position = 100 - position;
$media.style[end] = position + '%';
$media.style['margin-' + end] = side * (position / -100) + 'px';
}
return;
}
// Length-based values (e.g. 10px / 10em)
else {
$media.style[start] = position;
}
};
/**
* Calculate & set object-fit
*
* @param {node} $media - img/video/picture element
*/
var objectFit = function($media) {
// IE 10- data polyfill
var fit = $media.dataset
? $media.dataset.objectFit
: $media.getAttribute('data-object-fit');
var position = $media.dataset
? $media.dataset.objectPosition
: $media.getAttribute('data-object-position');
// Default fallbacks
fit = fit || 'cover';
position = position || '50% 50%';
// If necessary, make the parent container work with absolutely positioned elements
var $container = $media.parentNode;
checkParentContainer($container);
// Check for any pre-set CSS which could mess up image calculations
checkMediaProperties($media);
// Reset any pre-set width/height CSS and handle fit positioning
$media.style.position = 'absolute';
$media.style.width = 'auto';
$media.style.height = 'auto';
// `scale-down` chooses either `none` or `contain`, whichever is smaller
if (fit === 'scale-down') {
if (
$media.clientWidth < $container.clientWidth &&
$media.clientHeight < $container.clientHeight
) {
fit = 'none';
} else {
fit = 'contain';
}
}
// `none` (width/height auto) and `fill` (100%) and are straightforward
if (fit === 'none') {
setPosition('x', $media, position);
setPosition('y', $media, position);
return;
}
if (fit === 'fill') {
$media.style.width = '100%';
$media.style.height = '100%';
setPosition('x', $media, position);
setPosition('y', $media, position);
return;
}
// `cover` and `contain` must figure out which side needs covering, and add CSS positioning & centering
$media.style.height = '100%';
if (
(fit === 'cover' && $media.clientWidth > $container.clientWidth) ||
(fit === 'contain' && $media.clientWidth < $container.clientWidth)
) {
$media.style.top = '0';
$media.style.marginTop = '0';
setPosition('x', $media, position);
} else {
$media.style.width = '100%';
$media.style.height = 'auto';
$media.style.left = '0';
$media.style.marginLeft = '0';
setPosition('y', $media, position);
}
};
/**
* Initialize plugin
*
* @param {node} media - Optional specific DOM node(s) to be polyfilled
*/
var objectFitPolyfill = function(media) {
if (typeof media === 'undefined' || media instanceof Event) {
// If left blank, or a default event, all media on the page will be polyfilled.
media = document.querySelectorAll('[data-object-fit]');
} else if (media && media.nodeName) {
// If it's a single node, wrap it in an array so it works.
media = [media];
} else if (typeof media === 'object' && media.length && media[0].nodeName) {
// If it's an array of DOM nodes (e.g. a jQuery selector), it's fine as-is.
media = media;
} else {
// Otherwise, if it's invalid or an incorrect type, return false to let people know.
return false;
}
for (var i = 0; i < media.length; i++) {
if (!media[i].nodeName) continue;
var mediaType = media[i].nodeName.toLowerCase();
if (mediaType === 'img') {
if (edgePartialSupport) continue; // Edge supports object-fit for images (but nothing else), so no need to polyfill
if (media[i].complete) {
objectFit(media[i]);
} else {
media[i].addEventListener('load', function() {
objectFit(this);
});
}
} else if (mediaType === 'video') {
if (media[i].readyState > 0) {
objectFit(media[i]);
} else {
media[i].addEventListener('loadedmetadata', function() {
objectFit(this);
});
}
} else {
objectFit(media[i]);
}
}
return true;
};
if (document.readyState === 'loading') {
// Loading hasn't finished yet
document.addEventListener('DOMContentLoaded', objectFitPolyfill);
} else {
// `DOMContentLoaded` has already fired
objectFitPolyfill();
}
window.addEventListener('resize', objectFitPolyfill);
window.objectFitPolyfill = objectFitPolyfill;
})();
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