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add more data attributes #154

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17 changes: 17 additions & 0 deletions index.html
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Original file line number Diff line number Diff line change
Expand Up @@ -147,6 +147,23 @@ <h2>Callback</h2>
&nbsp;&nbsp;});<br>
});</code>

<h2>More data options</h2>
<p>
If you want to use more data-src options for a different purpose you can use the dataOptions parameter.
The dataOptions is an array of [function, data-attribute].</p>
<code>
var dataOptions = [<br>
[&nbsp;&nbsp;<span class="blue">function</span>()<br/> &nbsp;&nbsp; {&nbsp;&nbsp;return window.innerWidth < 991; },<br/> &nbsp;&nbsp;<span class="red">"data-src-small"</span><br/> ],<br>
[&nbsp;&nbsp;<span class="blue">function</span>()<br/> &nbsp;&nbsp; { return window.devicePixelRatio > 1; },<br/> &nbsp;&nbsp; <span class="red">"data-src-retina"</span><br/>]<br>
];<br>
</code>

<code>&lt;img <span class="blue">data-src-small=</span><span class="red">"corgi.png"</span> <span class="blue">data-src-retina=</span><span class="red">"corgiretina.png"</span><span class="blue">data-src=</span><span class="red">"normalcorgi.png"</span> /></code>

<p>
The code gets a list of data-options. If the condition is valid, the code tries to get the value of the data attribute in the img tag. If it can't, tries with the next data attribute.
</p>

<h2>Trigger</h2>
<p>You can still trigger image loading whenever you need.</p>
<p>All you have to do is select the images you want to "unveil" and trigger the event:</p>
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53 changes: 37 additions & 16 deletions jquery.unveil.js
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Original file line number Diff line number Diff line change
Expand Up @@ -8,35 +8,40 @@
* https://github.com/luis-almeida
*/

;(function($) {

$.fn.unveil = function(threshold, callback) {
; (function ($) {

$.fn.unveil = function (threshold, dataOptions, callback) {
var $w = $(window),
th = threshold || 0,
retina = window.devicePixelRatio > 1,
attrib = retina? "data-src-retina" : "data-src",
images = this,
loaded;

this.one("unveil", function() {
var source = this.getAttribute(attrib);
source = source || this.getAttribute("data-src");
th = threshold || 0,
images = this,
loaded,
attrib = [];

dataSrcOptions();

this.one("unveil", function () {
var source = undefined;
attrib.every(element => {
source = this.getAttribute(element);
if (source) return false;
return true;
})

if (source) {
this.setAttribute("src", source);
if (typeof callback === "function") callback.call(this);
}
});

function unveil() {
var inview = images.filter(function() {
var inview = images.filter(function () {
var $e = $(this);
if ($e.is(":hidden")) return;

var wt = $w.scrollTop(),
wb = wt + $w.height(),
et = $e.offset().top,
eb = et + $e.height();
wb = wt + $w.height(),
et = $e.offset().top,
eb = et + $e.height();

return eb >= wt - th && et <= wb + th;
});
Expand All @@ -45,6 +50,22 @@
images = images.not(loaded);
}

function isRetina() {
return window.devicePixelRatio > 1;
}

function dataSrcOptions() {
dataOptions.push([isRetina, "data-src-retina"]);
if (dataOptions != undefined && dataOptions.length > 0) {
dataOptions.forEach(element => {
if (element != undefined && element.length > 1 && typeof element[0] === "function" && element[0]())
attrib.push(element[1]);
})
}

attrib.push("data-src");
}

$w.on("scroll.unveil resize.unveil lookup.unveil", unveil);

unveil();
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