init

_extensions/shafayetShafee/metropolis-beamer/resources/js/add_header.js

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+/**
+ * reveal-header
+ * A filter that adds header text and logo.
+ * 
+ * MIT License
+ * Copyright (c) 2023-2024 Shafayet Khan Shafee.
+ */
+
+function header() {
+  
+  // add the header structure as the firstChild of div.reveal-header
+  function add_header() {
+    let header = document.querySelector("div.reveal-header");
+    let reveal = document.querySelector(".reveal");
+    reveal.insertBefore(header, reveal.firstChild);
+    
+    let header_title_p_placeholder = document.querySelector('div.header-title > p');
+    let header_title_h2_placeholder = document.createElement('h2');
+    header_title_p_placeholder.replaceWith(header_title_h2_placeholder);
+    
+    logo_img = document.querySelector('.header-logo > img');
+    if (logo_img?.getAttribute('src') == null) {
+      if (logo_img?.getAttribute('data-src') != null) {
+        logo_img.src = logo_img?.getAttribute('data-src') || "";
+        logo_img.removeAttribute('data-src'); 
+      };
+    };
+  };
+  
+  
+  function make_h2_title() {
+    let h2_text = Reveal.getCurrentSlide().getAttribute('data-h2-text');
+    let header_title_placeholder = document.querySelector('div.header-title > h2');
+    header_title_placeholder.innerText = h2_text;
+    
+    let header_div = document.querySelector('div.reveal-header');
+    
+    if(Reveal.getCurrentSlide().id == 'title-slide' ||
+       Reveal.getCurrentSlide().classList.contains('title-slide') || h2_text == ''
+       ) {
+      header_div.style.visibility = 'hidden';
+    } else {
+      header_div.style.visibility = 'visible';
+      header_title_placeholder.style.color = 'white';
+    };
+  };
+  
+  
+  function linkify_logo(logo, href) {
+    const logo_cloned = logo.cloneNode(true);
+    const link = document.createElement('a');
+    link.href = href;
+    link.target = '_blank';
+    link.appendChild(logo_cloned);
+    logo.replaceWith(link);
+  };
+    
+  function get_clean_attrs(elem, attrName) {
+    let attrVal = elem.getAttribute(attrName);
+    if (attrVal != null) {
+     elem.removeAttribute(attrName); 
+    }
+    return attrVal;
+  };
+  
+  
+  if (Reveal.isReady()) {
+    add_header();
+    
+    const slides = Reveal.getSlides();
+    slides.forEach(slide => {
+      const h2Element = slide.querySelector('h2');
+      
+      if (h2Element) {
+        h2Element.style.display = 'none';
+        const h2Text = h2Element.textContent;
+        slide.setAttribute('data-h2-text', h2Text);
+      } else {
+        slide.setAttribute('data-h2-text', '');
+      };
+  });
+    
+    make_h2_title();
+    
+    /*************** linkifying the header and footer logo ********************/
+    const header_logo = document.querySelector('div.header-logo');
+    if (header_logo != null) {
+      const header_logo_link = get_clean_attrs(header_logo, 'data-header-logo-link');
+      const footer_logo_link = get_clean_attrs(header_logo, 'data-footer-logo-link');
+      
+      if (header_logo_link != null) {
+        const header_logo_img = document.querySelector('div.header-logo').firstElementChild;
+        linkify_logo(header_logo_img, header_logo_link);
+      };
+      
+    };
+    /****************************** END ***************************************/
+    
+    Reveal.on( 'slidechanged', event => {
+      make_h2_title();
+    });
+    
+  };
+};
+
+
+window.addEventListener("load", (event) => {
+  header();
+});