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PHP

CSS image preloading

<?php
/* 
= Render hidden div in page to preload images
* WordPress: 3.3.1
* Version: 1.0
* URL: elbone.com.au
* Files: functions.php
*/
add_action('get_header', 'elbone_image_preloader');
if (!function_exists('elbone_image_preloader')) {    	
	function elbone_image_preloader() {
		$folder = '/images/'; // images directory in theme
		$dir = get_stylesheet_directory().$folder;
		$url = get_stylesheet_directory_uri().$folder;
		$types = array('jpg','gif','png');
		$files = array();
  		if ($handle = opendir($dir)) {
    		while(false !== ($file = readdir($handle))) {
      			$extension = strtolower(substr(strrchr($file,'.'),1));
      			if($extension && in_array($extension, $types)) {
        			$files[] = $file;
      			}
    		}
    		closedir($handle);
		}
		if(count($files)) {
  			$i = 0;
  			echo "\n", '<div style="display: none">', "\n";
  			echo '<!-- Preloaded images: ('.count($files).') -->', "\n";
  			foreach($files as $index => $file) {
  				$i++;
				echo '<img data-count="'.$i.'" src="'.$url.$file.'" />', "\n";
			}
			echo '</div>', "\n";	
		}
	}
}
?>
https://snipt.net/embed/096b75026b8b7fed1a917c5d99ebfa13/
/raw/096b75026b8b7fed1a917c5d99ebfa13/
096b75026b8b7fed1a917c5d99ebfa13
php
PHP
38
2019-08-19T17:13:13
True
False
False
/api/public/snipt/40682/
css-image-preloading
<table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><a href="#L-1"> 1</a> <a href="#L-2"> 2</a> <a href="#L-3"> 3</a> <a href="#L-4"> 4</a> <a href="#L-5"> 5</a> <a href="#L-6"> 6</a> <a href="#L-7"> 7</a> <a href="#L-8"> 8</a> <a href="#L-9"> 9</a> <a href="#L-10">10</a> <a href="#L-11">11</a> <a href="#L-12">12</a> <a href="#L-13">13</a> <a href="#L-14">14</a> <a href="#L-15">15</a> <a href="#L-16">16</a> <a href="#L-17">17</a> <a href="#L-18">18</a> <a href="#L-19">19</a> <a href="#L-20">20</a> <a href="#L-21">21</a> <a href="#L-22">22</a> <a href="#L-23">23</a> <a href="#L-24">24</a> <a href="#L-25">25</a> <a href="#L-26">26</a> <a href="#L-27">27</a> <a href="#L-28">28</a> <a href="#L-29">29</a> <a href="#L-30">30</a> <a href="#L-31">31</a> <a href="#L-32">32</a> <a href="#L-33">33</a> <a href="#L-34">34</a> <a href="#L-35">35</a> <a href="#L-36">36</a> <a href="#L-37">37</a> <a href="#L-38">38</a></pre></div></td><td class="code"><div class="highlight"><pre><span></span><span id="L-1"><a name="L-1"></a><span class="cp">&lt;?php</span> </span><span id="L-2"><a name="L-2"></a><span class="cm">/* </span> </span><span id="L-3"><a name="L-3"></a><span class="cm">= Render hidden div in page to preload images</span> </span><span id="L-4"><a name="L-4"></a><span class="cm">* WordPress: 3.3.1</span> </span><span id="L-5"><a name="L-5"></a><span class="cm">* Version: 1.0</span> </span><span id="L-6"><a name="L-6"></a><span class="cm">* URL: elbone.com.au</span> </span><span id="L-7"><a name="L-7"></a><span class="cm">* Files: functions.php</span> </span><span id="L-8"><a name="L-8"></a><span class="cm">*/</span> </span><span id="L-9"><a name="L-9"></a><span class="nx">add_action</span><span class="p">(</span><span class="s1">&#39;get_header&#39;</span><span class="p">,</span> <span class="s1">&#39;elbone_image_preloader&#39;</span><span class="p">);</span> </span><span id="L-10"><a name="L-10"></a><span class="k">if</span> <span class="p">(</span><span class="o">!</span><span class="nb">function_exists</span><span class="p">(</span><span class="s1">&#39;elbone_image_preloader&#39;</span><span class="p">))</span> <span class="p">{</span> </span><span id="L-11"><a name="L-11"></a> <span class="k">function</span> <span class="nf">elbone_image_preloader</span><span class="p">()</span> <span class="p">{</span> </span><span id="L-12"><a name="L-12"></a> <span class="nv">$folder</span> <span class="o">=</span> <span class="s1">&#39;/images/&#39;</span><span class="p">;</span> <span class="c1">// images directory in theme</span> </span><span id="L-13"><a name="L-13"></a> <span class="nv">$dir</span> <span class="o">=</span> <span class="nx">get_stylesheet_directory</span><span class="p">()</span><span class="o">.</span><span class="nv">$folder</span><span class="p">;</span> </span><span id="L-14"><a name="L-14"></a> <span class="nv">$url</span> <span class="o">=</span> <span class="nx">get_stylesheet_directory_uri</span><span class="p">()</span><span class="o">.</span><span class="nv">$folder</span><span class="p">;</span> </span><span id="L-15"><a name="L-15"></a> <span class="nv">$types</span> <span class="o">=</span> <span class="k">array</span><span class="p">(</span><span class="s1">&#39;jpg&#39;</span><span class="p">,</span><span class="s1">&#39;gif&#39;</span><span class="p">,</span><span class="s1">&#39;png&#39;</span><span class="p">);</span> </span><span id="L-16"><a name="L-16"></a> <span class="nv">$files</span> <span class="o">=</span> <span class="k">array</span><span class="p">();</span> </span><span id="L-17"><a name="L-17"></a> <span class="k">if</span> <span class="p">(</span><span class="nv">$handle</span> <span class="o">=</span> <span class="nb">opendir</span><span class="p">(</span><span class="nv">$dir</span><span class="p">))</span> <span class="p">{</span> </span><span id="L-18"><a name="L-18"></a> <span class="k">while</span><span class="p">(</span><span class="k">false</span> <span class="o">!==</span> <span class="p">(</span><span class="nv">$file</span> <span class="o">=</span> <span class="nb">readdir</span><span class="p">(</span><span class="nv">$handle</span><span class="p">)))</span> <span class="p">{</span> </span><span id="L-19"><a name="L-19"></a> <span class="nv">$extension</span> <span class="o">=</span> <span class="nb">strtolower</span><span class="p">(</span><span class="nb">substr</span><span class="p">(</span><span class="nb">strrchr</span><span class="p">(</span><span class="nv">$file</span><span class="p">,</span><span class="s1">&#39;.&#39;</span><span class="p">),</span><span class="mi">1</span><span class="p">));</span> </span><span id="L-20"><a name="L-20"></a> <span class="k">if</span><span class="p">(</span><span class="nv">$extension</span> <span class="o">&amp;&amp;</span> <span class="nb">in_array</span><span class="p">(</span><span class="nv">$extension</span><span class="p">,</span> <span class="nv">$types</span><span class="p">))</span> <span class="p">{</span> </span><span id="L-21"><a name="L-21"></a> <span class="nv">$files</span><span class="p">[]</span> <span class="o">=</span> <span class="nv">$file</span><span class="p">;</span> </span><span id="L-22"><a name="L-22"></a> <span class="p">}</span> </span><span id="L-23"><a name="L-23"></a> <span class="p">}</span> </span><span id="L-24"><a name="L-24"></a> <span class="nb">closedir</span><span class="p">(</span><span class="nv">$handle</span><span class="p">);</span> </span><span id="L-25"><a name="L-25"></a> <span class="p">}</span> </span><span id="L-26"><a name="L-26"></a> <span class="k">if</span><span class="p">(</span><span class="nb">count</span><span class="p">(</span><span class="nv">$files</span><span class="p">))</span> <span class="p">{</span> </span><span id="L-27"><a name="L-27"></a> <span class="nv">$i</span> <span class="o">=</span> <span class="mi">0</span><span class="p">;</span> </span><span id="L-28"><a name="L-28"></a> <span class="k">echo</span> <span class="s2">&quot;</span><span class="se">\n</span><span class="s2">&quot;</span><span class="p">,</span> <span class="s1">&#39;&lt;div style=&quot;display: none&quot;&gt;&#39;</span><span class="p">,</span> <span class="s2">&quot;</span><span class="se">\n</span><span class="s2">&quot;</span><span class="p">;</span> </span><span id="L-29"><a name="L-29"></a> <span class="k">echo</span> <span class="s1">&#39;&lt;!-- Preloaded images: (&#39;</span><span class="o">.</span><span class="nb">count</span><span class="p">(</span><span class="nv">$files</span><span class="p">)</span><span class="o">.</span><span class="s1">&#39;) --&gt;&#39;</span><span class="p">,</span> <span class="s2">&quot;</span><span class="se">\n</span><span class="s2">&quot;</span><span class="p">;</span> </span><span id="L-30"><a name="L-30"></a> <span class="k">foreach</span><span class="p">(</span><span class="nv">$files</span> <span class="k">as</span> <span class="nv">$index</span> <span class="o">=&gt;</span> <span class="nv">$file</span><span class="p">)</span> <span class="p">{</span> </span><span id="L-31"><a name="L-31"></a> <span class="nv">$i</span><span class="o">++</span><span class="p">;</span> </span><span id="L-32"><a name="L-32"></a> <span class="k">echo</span> <span class="s1">&#39;&lt;img data-count=&quot;&#39;</span><span class="o">.</span><span class="nv">$i</span><span class="o">.</span><span class="s1">&#39;&quot; src=&quot;&#39;</span><span class="o">.</span><span class="nv">$url</span><span class="o">.</span><span class="nv">$file</span><span class="o">.</span><span class="s1">&#39;&quot; /&gt;&#39;</span><span class="p">,</span> <span class="s2">&quot;</span><span class="se">\n</span><span class="s2">&quot;</span><span class="p">;</span> </span><span id="L-33"><a name="L-33"></a> <span class="p">}</span> </span><span id="L-34"><a name="L-34"></a> <span class="k">echo</span> <span class="s1">&#39;&lt;/div&gt;&#39;</span><span class="p">,</span> <span class="s2">&quot;</span><span class="se">\n</span><span class="s2">&quot;</span><span class="p">;</span> </span><span id="L-35"><a name="L-35"></a> <span class="p">}</span> </span><span id="L-36"><a name="L-36"></a> <span class="p">}</span> </span><span id="L-37"><a name="L-37"></a><span class="p">}</span> </span><span id="L-38"><a name="L-38"></a><span class="cp">?&gt;</span><span class="x"></span> </span></pre></div> </td></tr></table>
WordPress, header, images, preload