Added ElementScrollFader effect

public/animation/fade/ElementScrollFader.jsx

@@ -0,0 +1,77 @@
+// Copyright (c) 2018 Dominic Masters
+//
+// MIT License
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+import React from 'react';
+
+class ElementScrollFader extends React.Component {
+  constructor(props) {
+    super(props);
+
+    this.state = { visible: false };
+    this.onScrollBound = this.onScroll.bind(this);
+  }
+
+  componentDidMount() {
+    document.addEventListener('scroll', this.onScrollBound, true);
+  }
+
+  onScroll(e) {
+    //Get bounds
+    var rect = this.refs.fader.getBoundingClientRect();
+    //If our top is at least half way UP the page, show
+    if(rect.top > window.innerHeight / 2) return;
+    this.setState({visible: true});
+    this.detachListener();//stop Listening
+  }
+
+  componentWillUnmount() {
+    this.detachListener();
+  }
+
+  detachListener() {
+    document.removeEventListener('scroll', this.onScrollBound);
+  }
+
+  render() {
+    let clazz = "o-element-scroll-fader";
+
+    if(this.props.from) {
+      clazz += " from-" + this.props.from
+    } else {
+      clazz += " from-top";
+    }
+    if(this.state.visible) {
+      clazz += " is-visible";
+    }
+
+    if(this.props.className) clazz += " " + this.props.className;
+
+    return (
+      <div className={ clazz } ref="fader">
+        { this.props.children}
+      </div>
+    );
+  }
+}
+
+export default ElementScrollFader;