Add copy functionality to code boxes

slides/template.html

@@ -46,7 +46,51 @@
 				]
             });
             Reveal.configure({ slideNumber: 'c/t' });
-			new ClipboardJS('.hljs');
+
+			Reveal.addEventListener( 'ready', function(event){
+				var snippets = document.querySelectorAll('pre > code');
+				[].forEach.call(snippets, function(snippet) {
+					snippet.insertAdjacentHTML("beforebegin", "<button class='btn-copy' data-clipboard-snippet><img class='clippy' width=13 src='/img/clippy.svg' alt='Copy to clipboard'></button>");
+				});
+
+				var clipboardSnippets = new ClipboardJS('[data-clipboard-snippet]', {
+					target: function(trigger) {
+						return trigger.nextElementSibling;
+					}
+				});
+
+				clipboardSnippets.on('success', function(e) {
+					e.clearSelection();
+					showTooltip(e.trigger, "Copied to clipboard");
+				});
+				clipboardSnippets.on('error', function(e) {
+					showTooltip(e.trigger, fallbackMessage(e.action));
+				});
+				var btns = document.querySelectorAll('.btn-copy');
+				for (var i = 0; i < btns.length; i++) {
+					btns[i].addEventListener('mouseleave', function(e) {
+						e.currentTarget.setAttribute('class', 'btn-copy');
+						e.currentTarget.removeAttribute('aria-label');
+					});
+				}
+			});
+
+			function showTooltip(elem, msg) {
+				elem.setAttribute('class', 'btn-copy tooltipped tooltipped-s');
+				elem.setAttribute('aria-label', msg);
+			}
+			function fallbackMessage(action) {
+				var actionMsg = '';
+				var actionKey = (action === 'cut' ? 'X' : 'C');
+				if (/iPhone|iPad/i.test(navigator.userAgent)) {
+					actionMsg = 'No support :(';
+				} else if (/Mac/i.test(navigator.userAgent)) {
+					actionMsg = 'Press ⌘-' + actionKey + ' to ' + action;
+				} else {
+					actionMsg = 'Press Ctrl-' + actionKey + ' to ' + action;
+				}
+				return actionMsg;
+			}
 		</script>
 	</body>
 </html>

slides/workshop.css

@@ -62,4 +62,74 @@ body {
   bottom: unset;
   font-size: 16px;
   background-color: #0075BC;
-}
+}
+
+/* Control the look and feel of the copy box applied to code sections */
+.btn-copy[disabled] .clippy {
+  opacity: .3;
+}
+pre .btn-copy {
+  -webkit-transition: opacity 0.3s ease-in-out;
+  -o-transition: opacity 0.3s ease-in-out;
+  transition: opacity 0.3s ease-in-out;
+  opacity: 0;
+  padding: 2px 6px;
+  float: right;
+}
+pre .btn-copy img {
+  margin: 0;
+  border: 0;
+}
+pre:hover .btn-copy {
+  opacity: 1;
+}
+.tooltipped {
+  position: relative
+}
+.tooltipped:after {
+  position: absolute;
+  z-index: 1000000;
+  display: none;
+  padding: 5px 8px;
+  font: normal normal 11px/1.5 Helvetica, arial, nimbussansl, liberationsans, freesans, clean, sans-serif, "Segoe UI Emoji", "Segoe UI Symbol";
+  color: #fff;
+  text-align: center;
+  text-decoration: none;
+  text-shadow: none;
+  text-transform: none;
+  letter-spacing: normal;
+  word-wrap: break-word;
+  white-space: pre;
+  pointer-events: none;
+  content: attr(aria-label);
+  background: rgba(0, 0, 0, 0.8);
+  border-radius: 3px;
+  -webkit-font-smoothing: subpixel-antialiased
+}
+.tooltipped:before {
+  position: absolute;
+  z-index: 1000001;
+  display: none;
+  width: 0;
+  height: 0;
+  color: rgba(0, 0, 0, 0.8);
+  pointer-events: none;
+  content: "";
+  border: 5px solid transparent
+}
+.tooltipped:hover:before, .tooltipped:hover:after, .tooltipped:active:before, .tooltipped:active:after, .tooltipped:focus:before, .tooltipped:focus:after {
+  display: inline-block;
+  text-decoration: none
+}
+.tooltipped-s:after, .tooltipped-se:after, .tooltipped-sw:after {
+  top: 100%;
+  right: 50%;
+  margin-top: 5px
+}
+.tooltipped-s:before, .tooltipped-se:before, .tooltipped-sw:before {
+  top: auto;
+  right: 50%;
+  bottom: -5px;
+  margin-right: -5px;
+  border-bottom-color: rgba(0, 0, 0, 0.8)
+}