scrollama
Version:
Lightweight scrollytelling library using IntersectionObserver
190 lines (184 loc) • 6.08 kB
HTML
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title>Scrollama Demo: Basic</title>
<meta name="description" content="Scrollama Demo: Error when steps are children of multiple scrollable elements" >
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
/* default / demo page */
* {
box-sizing: border-box;
}
html,
body {
margin: 0;
padding: 0;
font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
}
body {
font-weight: 300;
color: #2a2a2a;
height: 100vh;
}
main {
/* NO OVERFLOW HERE */
}
p,
h1,
h2,
h3,
h4,
a {
margin: 0;
font-weight: 300;
}
a,
a:visited,
a:hover {
color: #f30;
text-decoration: none;
border-bottom: 1px solid currentColor;
}
#intro {
max-width: 40rem;
margin: 1rem auto;
text-align: center;
}
.intro__overline {
font-size: 1.4rem;
}
.intro__hed {
font-size: 1.4rem;
margin: 1.5rem auto;
text-transform: uppercase;
font-weight: 900;
letter-spacing: 0.05em;
}
.intro__dek {
font-size: 1.4rem;
margin-bottom: 1rem;
}
/* demo */
#bottom-spacer {
height: 100vh;
}
/* scrollama */
#step-container-element {
position: relative;
height: 500px;
width: 50vw;
overflow-y: scroll;
}
.scroll__text {
position: relative;
padding: 0 1rem;
margin: 0 auto;
width: 33%;
}
.step {
margin: 2rem auto 4rem auto;
border: 1px solid #333;
background-color: #fff;
}
.step.is-active {
background-color: lightgoldenrodyellow;
}
.step p {
text-align: center;
padding: 1rem;
font-size: 1.5rem;
}
.section_title {
position: sticky;
top: 0;
}
nav {
position: fixed;
top: 0;
left: 0;
z-index: 1000;
background: white;
padding: 1rem;
}
</style>
</head>
<body>
<main>
<section id='intro'>
<p class='intro__overline'>
<a href='https://github.com/russellgoldenberg/scrollama'>scrollama.js</a>
</p>
<h1 class='intro__hed'>Scrollama throws an error when steps are children of a scrollable element</h1>
<p class="intro__dek">Calculating the scroll direction is problematic when steps are children of a scrollable element that isn't the page scroll. This page provides an example of what not to do: <strong>do NOT place steps inside a scrollable element</strong> with <em>overflowY: scroll</em> or <em>overflowY: auto</em> and fixed height.</p>
<p class="intro__dek">To demonstrate the incorrect behavior:</p>
<ul class="intro__dek">
<li>ensure that the olive-colored element intersects the trigger (the dotted line)</li>
<li>move the mouse pointer inside the olive-colored element</li>
<li>scroll up and down with the mouse pointer inside the colored container. You may have to scroll up and down several times before the direction calculation becomes incorrect</li>
</ul>
<p class="intro__dek"><strong>Notice that step events are not triggered correctly when the inner container scrolls without the window element scrolling.</strong></p>
</section>
</main>
<script src="./d3.v4.min.js"></script>
<script src='https://unpkg.com/intersection-observer@0.5.0/intersection-observer.js'></script>
<script src="../build/scrollama.js"></script>
<script>
function buildSection(title, parentSelector, sectionId, nSteps, stepHeight, background) {
var scroll = d3.select(parentSelector)
.append('section')
.append('div')
.classed('scroll__text', true)
.attr('id', sectionId)
.style('background', background);
scroll.append('div')
.append('h2')
.classed('section_title', true)
.html(title);
var data = d3.range(nSteps);
scroll.selectAll('div.step')
.data(data)
.enter()
.append('div')
.classed('step', true)
.attr('data-step', function (datum) { return datum.toString(); })
.style('height', stepHeight + 'px')
.append('p')
.html(function (datum) { return 'STEP ' + datum; });
return scroll.node();
}
function buildScroller(sectionId) {
var scroller = scrollama()
.setup({
step: '#' + sectionId + ' .step',
debug: true,
offset: 0.9,
progress: true,
})
.onStepEnter(function handleStepEnter(response) {
console.log(response.index, '-------- enter');
response.element.classList.add('is-active');
})
.onStepExit(function handleStepExit(response) {
console.log(response.index, '-------- exit');
response.element.classList.remove('is-active');
})
.onStepProgress(function handleStepProgress(response) {
console.log(response.index, '-------- progress -', response.progress);
});
// setup resize event
window.addEventListener('resize', scroller.resize);
}
function init() {
var scrollableStepContainerId = 'step-container-element';
buildSection("I'm a scrollable element containing steps", 'main', scrollableStepContainerId, 5, 150, 'olive');
buildScroller(scrollableStepContainerId);
d3.select('main').append('div')
.attr('id', 'bottom-spacer');
}
// kick things off
init();
</script>
</body>
</html>