Updated opacity handling around code fragment highlights.

app/com/gitpitch/views/frags/SlideshowCodeFragHighlightStyle.scala.html

@@ -1,23 +1,15 @@
     <style>
-      .reveal .slides section .fragment.current-only {
-        opacity: 1;
+    .reveal .slides section .fragment.current-only {
         visibility: visible;
         display: none;
-      }
-      .reveal .slides section .fragment.current-only.current-fragment {
+    }
+    .reveal .slides section .fragment.current-only.current-fragment {
         display: block;
-      }
-      .line { display: block; }
-      .line.focus { background: #fdf6e3; color: #657b83; }
-      .line.focus .hljs-comment, .line.focus .hljs-quote { color: #93a1a1; }
-      .line.focus .hljs-keyword, .line.focus .hljs-selector-tag, .line.focus .hljs-addition { color: #859900; }
-      .line.focus .hljs-number, .line.focus .hljs-string, .line.focus .hljs-meta .hljs-meta-string, .line.focus .hljs-literal, .line.focus .hljs-doctag, .line.focus .hljs-regexp { color: #2aa198; }
-      .line.focus .hljs-title, .line.focus .hljs-section, .line.focus .hljs-name, .line.focus .hljs-selector-id, .line.focus .hljs-selector-class { color: #268bd2; }
-      .line.focus .hljs-attribute, .line.focus .hljs-attr, .line.focus .hljs-variable, .line.focus .hljs-template-variable, .line.focus .hljs-class .hljs-title, .line.focus .hljs-type { color: #b58900; }
-      .line.focus .hljs-symbol, .line.focus .hljs-bullet, .line.focus .hljs-subst, .line.focus .hljs-meta, .line.focus .hljs-meta .hljs-keyword, .line.focus .hljs-selector-attr, .line.focus .hljs-selector-pseudo, .line.focus .hljs-link { color: #cb4b16; }
-      .line.focus .hljs-built_in, .line.focus .hljs-deletion { color: #dc322f; }
-      .line.focus .hljs-formula { background: #eee8d5; }
-      .line.focus .hljs-emphasis { font-style: italic; }
-      .line.focus .hljs-strong { font-weight: bold; }
-      .yellow-slide .line.focus:nth-child(2) { background: yellow; }
-    </style>
+    }
+    .line {
+        display: block;
+    }
+    .line.focus {
+        /* opacity: 1.0; */
+    }
+    </style>

app/com/gitpitch/views/frags/SlideshowReveal.scala.html

@@ -38,7 +38,7 @@
                 { src: "@deps.revealjs(offline, ssm.fetchRevealVersionOverride())/plugin/highlight/highlight.js", async: true, callback: function() { hljs.initHighlightingOnLoad(); } },
                 } else {
                 { src: '@deps.highlightjs(offline)/highlight.js' },
-                { src: '@deps.highlightjs(offline)/reveal-code-focus.js',
+                { src: '@deps.highlightjs(offline)/reveal-code-focus-1.0.0-mod.js',
                   callback: function() {
                     RevealCodeFocus();
                   }

public/libs/highlight.js/9.6.0/reveal-code-focus-1.0.0-mod.js

@@ -0,0 +1,270 @@
+/*!
+ * reveal-code-focus 1.0.0
+ * Copyright 2015-2017 Benjamin Tan <https://demoneaux.github.io/>
+ * Available under MIT license <https://github.com/demoneaux/reveal-code-focus/blob/master/LICENSE>
+ *
+ * Modified by @gitpitch with support for updateCodeOpacity() and
+ * resetCodeOpacity() respectively.
+ */
+;(function(window, Reveal, hljs) {
+  if (typeof window.RevealCodeFocus == 'function') {
+    return;
+  }
+
+  var currentSlide, currentFragments, scrollToFocused = true, prevSlideData = null;
+
+  // Iterates through `array`, running `callback` for each `array` element.
+  function forEach(array, callback) {
+    var i = -1, length = array ? array.length : 0;
+    while (++i < length) {
+      callback(array[i]);
+    }
+  }
+
+  function indexOf(array, elem) {
+    var i = -1, length = array ? array.length : 0;
+    while (++i < length) {
+      if (array[i] === elem) {
+        return i;
+      }
+    }
+  }
+
+  function initialize(e) {
+    // Initialize code only once.
+    // TODO: figure out why `initialize` is being called twice.
+    if (initialize.ran) {
+      return;
+    }
+    initialize.ran = true;
+
+    // TODO: mark as parsed.
+    forEach(document.querySelectorAll('pre code'), function(element) {
+      // Trim whitespace if the `data-trim` attribute is present.
+      if (element.hasAttribute('data-trim') && typeof element.innerHTML.trim == 'function') {
+        element.innerHTML = element.innerHTML.trim();
+      }
+
+      // Highlight code using highlight.js.
+      hljs.highlightBlock(element);
+
+      // Split highlighted code into lines.
+      var openTags = [], reHtmlTag = /<(\/?)span(?:\s+(?:class=(['"])hljs-.*?\2)?\s*|\s*)>/g;
+      element.innerHTML = element.innerHTML.replace(/(.*?)\r?\n/g, function(_, string) {
+        if (!string) {
+          return '<span class=line>&nbsp;</span>';
+        }
+        var openTag, stringPrepend;
+        // Re-open all tags that were previously closed.
+        if (openTags.length) {
+          stringPrepend = openTags.join('');
+        }
+        // Match all HTML `<span>` tags.
+        reHtmlTag.lastIndex = 0;
+        while (openTag = reHtmlTag.exec(string)) {
+          // If it is a closing tag, remove the opening tag from the list.
+          if (openTag[1]) {
+            openTags.pop();
+          }
+          // Otherwise if it is an opening tag, push it to the list.
+          else {
+            openTags.push(openTag[0]);
+          }
+        }
+        // Close all opened tags, so that strings can be wrapped with `span.line`.
+        if (openTags.length) {
+          string += Array(openTags.length + 1).join('</span>');
+        }
+        if (stringPrepend) {
+          string = stringPrepend + string;
+        }
+        return '<span class=line>' + string + '</span>';
+      });
+    });
+
+    Reveal.addEventListener('slidechanged', updateCurrentSlide);
+
+    Reveal.addEventListener('fragmentshown', function(e) {
+      focusFragment(e.fragment);
+    });
+
+    // TODO: make this configurable.
+    // When a fragment is hidden, clear the current focused fragment,
+    // and focus on the previous fragment.
+    Reveal.addEventListener('fragmenthidden', function(e) {
+      var index = indexOf(currentFragments, e.fragment);
+      focusFragment(currentFragments[index - 1]);
+    });
+
+    updateCurrentSlide(e);
+  }
+  initialize.ran = false;
+
+  function updateCurrentSlide(e) {
+    currentSlide = e.currentSlide;
+    currentFragments = currentSlide.getElementsByClassName('fragment');
+    clearPreviousFocus();
+
+    // If moving back to a previous slide…
+    if (
+        currentFragments.length &&
+        prevSlideData &&
+        (
+          prevSlideData.indexh > e.indexh ||
+          (prevSlideData.indexh == e.indexh && prevSlideData.indexv > e.indexv)
+        )
+    ) {
+      // …return to the last fragment and highlight the code.
+      while (Reveal.nextFragment()) {}
+      var currentFragment = currentFragments[currentFragments.length - 1];
+      currentFragment.classList.add('current-fragment');
+      focusFragment(currentFragment);
+    }
+
+    // Update previous slide information.
+    prevSlideData = {
+      'indexh': e.indexh,
+      'indexv': e.indexv
+    };
+
+  }
+
+  // Removes any previously focused lines.
+  function clearPreviousFocus() {
+    forEach(currentSlide.querySelectorAll('pre code .line.focus'), function(line) {
+      line.classList.remove('focus');
+    });
+  }
+
+  function updateCodeOpacity() {
+
+    linesOfCode = currentSlide.querySelectorAll('pre code .line')
+    linesInFocus = currentSlide.querySelectorAll('pre code .line.focus')
+
+    if(linesInFocus.length == 0) {
+        // No linesInFocus, make all lines full opacity.
+        forEach(linesOfCode, function(line) {
+          line.style.opacity = 1.0;
+        });
+    } else {
+        // Some linesInFocus, reduce opacity on all linesNotInFocus.
+        forEach(linesOfCode, function(line) {
+            if(line.classList.contains('focus')) {
+                line.style.opacity = 1.0;
+            } else {
+                line.style.opacity = 0.20;
+            }
+        });
+    }
+
+  }
+
+  function resetCodeOpacity() {
+
+    linesOfCode = currentSlide.querySelectorAll('pre code .line')
+
+    forEach(linesOfCode, function(line) {
+      line.style.opacity = 1.0;
+    });
+
+  }
+
+  function focusFragment(fragment) {
+    clearPreviousFocus();
+    if (!fragment) {
+      resetCodeOpacity();
+      return;
+    }
+
+    var lines = fragment.getAttribute('data-code-focus');
+    if (!lines) {
+      return;
+    }
+
+    var codeBlock = parseInt(fragment.getAttribute('data-code-block'));
+    if (isNaN(codeBlock)) {
+      codeBlock = 1;
+    }
+
+    var preElems = currentSlide.querySelectorAll('pre');
+    if (!preElems.length) {
+      return;
+    }
+
+    var pre = preElems[codeBlock - 1];
+    var code = pre.querySelectorAll('code .line');
+    if (!code.length) {
+      return;
+    }
+
+    var topLineNumber, bottomLineNumber;
+
+    forEach(lines.split(','), function(line) {
+      lines = line.split('-');
+      if (lines.length == 1) {
+        focusLine(lines[0]);
+      } else {
+        var i = lines[0] - 1, j = lines[1];
+
+        while (++i <= j) {
+          focusLine(i);
+        }
+      }
+    });
+
+    updateCodeOpacity();
+
+    function focusLine(lineNumber) {
+      // Convert from 1-based index to 0-based index.
+      lineNumber -= 1;
+
+      var line = code[lineNumber];
+      if (!line) {
+        return;
+      }
+
+      line.classList.add('focus');
+
+      if (scrollToFocused) {
+        if (topLineNumber == null) {
+          topLineNumber = bottomLineNumber = lineNumber;
+        } else {
+          if (lineNumber < topLineNumber) {
+            topLineNumber = lineNumber;
+          }
+          if (lineNumber > bottomLineNumber) {
+            bottomLineNumber = lineNumber;
+          }
+        }
+      }
+    }
+
+    if (scrollToFocused && topLineNumber != null) {
+      var topLine =  code[topLineNumber];
+      var bottomLine = code[bottomLineNumber];
+      var codeParent = topLine.parentNode;
+      var scrollTop = topLine.offsetTop;
+      var scrollBottom = bottomLine.offsetTop + bottomLine.clientHeight;
+      codeParent.scrollTop = scrollTop - (codeParent.clientHeight - (scrollBottom - scrollTop)) / 2;
+    }
+
+  }
+
+  function RevealCodeFocus(options) {
+    options || (options = {
+      'scrollToFocused': true
+    });
+
+    if (options.scrollToFocused != null) {
+      scrollToFocused = options.scrollToFocused;
+    }
+
+    if (Reveal.isReady()) {
+      initialize({ 'currentSlide': Reveal.getCurrentSlide() });
+    } else {
+      Reveal.addEventListener('ready', initialize);
+    }
+  }
+
+  window.RevealCodeFocus = RevealCodeFocus;
+}(this, this.Reveal, this.hljs));