Commit fe0d6c74 authored by Rafael Weinstein's avatar Rafael Weinstein

Add initial SkyElement & city-list example

BUG=
R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/698653002
parent bcb84129
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<!--
// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
-->
<link rel="import"
href="../../framework/sky-element/sky-element.sky"
as="SkyElement" />
<link rel="import" href="city-data-service.sky" as="CityDataService" />
<link rel="import" href="city-sequence.sky" as="CitySequence" />
<template>
<style>
div {
font-size: 16px;
color: #FFF;
background-color: #333;
padding: 4px 4px 4px 12px;
}
</style>
<div>{{ state }}</div>
</template>
<script>
SkyElement({
name: 'state-header',
set datum(datum) {
this.state = datum.state;
}
});
</script>
<template>
<style>
div {
font-size: 12px;
font-weight: bold;
padding: 2px 4px 4px 12px;
background-color: #DDD;
}
</style>
<div>{{ letter }}</div>
</template>
<script>
SkyElement({
name: 'letter-header',
set datum(datum) {
this.letter = datum.letter;
}
});
</script>
<template>
<style>
:host {
display: flex;
font-size: 13px;
padding: 8px 4px 4px 12px;
border-bottom: 1px solid #EEE;
line-height: 15px;
overflow: hidden;
}
span {
display: inline;
}
#name {
font-weight: bold
}
#population {
color: #AAA;
}
</style>
<div>
<span id="name">{{ name }}</span>,
<span id="population">population {{ population }}</span>
</div>
</template>
<script>
SkyElement({
name: 'city-item',
set datum(datum) {
this.name = datum.name;
this.population = datum.population;
}
});
</script>
<template>
<style>
:host {
overflow: hidden;
position: absolute;
top: 0;
right: 0;
bottom: 0;
left: 0;
display: block;
background-color: #fff;
}
#scroller {
overflow-x: hidden;
overflow-y: auto;
perspective: 5px;
position: absolute;
left: 0;
right: 0;
top: 0;
bottom: 0;
}
#scroller::-webkit-scrollbar {
display:none;
}
#scrollarea {
will-change: transform;
transform-style: preserve-3d;
}
#contentarea {
position: absolute;
will-change: contents;
width: 100%;
}
.void {
display: none;
}
.position {
position: absolute;
left: 0;
right: 0;
}
</style>
<div id="scroller" fit>
<div id="scrollarea">
<div id="contentarea">
</div>
</div>
</div>
</template>
<script>
(function(global) {
"use strict";
var LOAD_LENGTH = 20;
var LOAD_BUFFER_PRE = LOAD_LENGTH * 4;
var LOAD_BUFFER_POST = LOAD_LENGTH * 4;
function Loader() {
this.loadingData = false;
this.data = null;
this.zeroIndex = 0;
this.loadIndex = 0;
}
Loader.prototype.localIndex = function(externalIndex) {
return externalIndex + this.zeroIndex;
}
Loader.prototype.externalIndex = function(localIndex) {
return localIndex - this.zeroIndex;
}
Loader.prototype.getItems = function() {
return this.data ? this.data.items : [];
}
Loader.prototype.maybeLoadMoreData = function(dataloadedCallback,
firstVisible) {
if (this.loadingData)
return;
if (firstVisible) {
this.loadIndex = this.externalIndex(
this.data.items.indexOf(firstVisible));
}
var localIndex = this.localIndex(this.loadIndex);
var loadedPre = 0;
var loadedPost = 0;
if (this.data) {
loadedPre = localIndex;
loadedPost = this.data.items.length - loadedPre;
}
var loadTime;
if (loadedPre >= LOAD_BUFFER_PRE && loadedPost >= LOAD_BUFFER_POST) {
if (window.startLoad) {
loadTime = new Date().getTime() - window.startLoad;
console.log('Load: ' + loadTime + 'ms');
window.startLoad = undefined;
}
return;
}
this.loadingData = true;
var loadIndex;
if (!this.data) {
// Initial batch
loadIndex = 0;
} else if (loadedPost < LOAD_BUFFER_POST) {
// Load forward first
loadIndex = this.data.items.length;
} else {
// Then load backward
loadIndex = -LOAD_LENGTH;
}
var self = this;
var externalIndex = this.externalIndex(loadIndex);
try {
CityDataService.service.then(function(cityService) {
return cityService.get(externalIndex, LOAD_LENGTH)
.then(function(cities) {
var indexOffset = 0;
var newData = new CitySequence(cities);
if (!self.data) {
self.data = newData;
} else if (loadIndex > 0) {
self.data.append(newData);
} else {
self.zeroIndex += LOAD_LENGTH;
indexOffset = LOAD_LENGTH;
newData.append(self.data);
self.data = newData;
}
self.loadingData = false;
dataloadedCallback(self.data, indexOffset);
});
}).catch(function(ex) {
console.log(ex.stack);
});
} catch (ex) {
console.log(ex.stack);
}
}
function Scroller() {
this.contentarea = null;
this.scroller = null;
this.contentTop = 0; // #contentarea's current top
this.scrollTop = 0; // #scrollarea's current top
this.scrollHeight = -1; // height of #scroller (the viewport)
this.lastScrollTop = 0; // last known scrollTop to compute deltas
}
Scroller.prototype.setup = function(scroller, scrollarea, contentarea) {
this.contentarea = contentarea;
this.scroller = scroller;
this.scrollHeight = scroller.offsetHeight;
scrollarea.style.height = (this.scrollHeight) * 4 + 'px';
this.reset();
}
Scroller.prototype.captureNewFrame = function(event) {
var scrollTop = event.target.scrollTop;
// Protect from re-entry.
if (this.lastScrollTop == scrollTop)
return false;
var scrollDown = scrollTop > this.lastScrollTop;
if (scrollDown) {
while (scrollTop > this.scrollHeight * 1.5) {
scrollTop -= this.scrollHeight;
this.contentTop -= this.scrollHeight;
}
} else {
while(scrollTop < this.scrollHeight * 1.5) {
scrollTop += this.scrollHeight;
this.contentTop += this.scrollHeight;
}
}
this.lastScrollTop = scrollTop;
event.target.scrollTop = scrollTop;
this.contentarea.style.top = this.contentTop + 'px';
this.scrollTop = scrollTop - this.contentTop;
return true;
}
Scroller.prototype.reset = function() {
if (!this.contentarea)
return;
this.scroller.scrollTop = this.scrollHeight;
this.lastScrollTop = this.scrollHeight;
this.contentarea.style.top = this.scrollHeight + 'px';
this.contentTop = this.scrollHeight;
this.scrollTop = 0;
}
// Current position and height of the scroller, that could
// be used (by Tiler, for example) to reason about where to
// place visible things.
Scroller.prototype.getCurrentFrame = function() {
return { top: this.scrollTop, height: this.scrollHeight };
}
Scroller.prototype.hasFrame = function() {
return this.scrollHeight != -1;
}
function Tile(datum, element, viewType, index) {
this.datum = datum;
this.element = element;
this.viewType = viewType;
this.index = index;
}
function Tiler(contentArea, views, viewHeights) {
this.contentArea = contentArea;
this.drawTop = 0;
this.drawBottom = 0;
this.firstItem = -1;
this.tiles = [];
this.viewHeights = viewHeights;
this.views = views;
}
Tiler.prototype.setupViews = function(scrollFrame) {
for (var type in this.viewHeights) {
this.initializeViewType(scrollFrame, type, this.viewHeights[type]);
}
}
Tiler.prototype.initializeViewType = function(scrollFrame, viewType,
height) {
var count = Math.ceil(scrollFrame.height / height) * 2;
var viewCache = this.views[viewType] = {
indices: [],
elements: []
};
var protoElement;
switch (viewType) {
case 'stateHeader':
protoElement = document.createElement('state-header');
break;
case 'letterHeader':
protoElement = document.createElement('letter-header');
break;
case 'cityItem':
protoElement = document.createElement('city-item');
break;
default:
console.warn('Unknown viewType: ' + viewType);
}
protoElement.style.display = 'none';
protoElement.style.height = height;
protoElement.classList.add('position');
for (var i = 0; i < count; i++) {
var clone = protoElement.cloneNode(false);
this.contentArea.appendChild(clone);
viewCache.elements.push(clone);
viewCache.indices.push(i);
}
}
Tiler.prototype.checkoutTile = function(viewType, datum, top) {
var viewCache = this.views[viewType];
var index = viewCache.indices.pop();
var element = viewCache.elements[index];
element.datum = datum;
element.style.display = '';
element.style.top = top + 'px';
return new Tile(datum, element, viewType, index);
}
Tiler.prototype.checkinTile = function(tile) {
if (!tile.element)
return;
tile.element.style.display = 'none';
this.views[tile.viewType].indices.push(tile.index);
}
Tiler.prototype.getFirstVisibleDatum = function(scrollFrame) {
var tiles = this.tiles;
var viewHeights = this.viewHeights;
var itemTop = this.drawTop - scrollFrame.top;
if (itemTop >= 0 && tiles.length)
return tiles[0].datum;
var tile;
for (var i = 0; i < tiles.length && itemTop < 0; i++) {
tile = tiles[i];
var height = viewHeights[tile.viewType];
itemTop += height;
}
return tile ? tile.datum : null;
}
Tiler.prototype.viewType = function(datum) {
switch (datum.headerOrder) {
case 1: return 'stateHeader';
case 2: return 'letterHeader';
default: return 'cityItem';
}
}
Tiler.prototype.drawTiles = function(scrollFrame, data) {
var tiles = this.tiles;
var viewHeights = this.viewHeights;
var buffer = Math.round(scrollFrame.height / 2);
var targetTop = scrollFrame.top - buffer;
var targetBottom = scrollFrame.top + scrollFrame.height + buffer;
// Collect down to targetTop
var first = tiles[0];
while (tiles.length &&
targetTop > this.drawTop + viewHeights[first.viewType]) {
var height = viewHeights[first.viewType];
this.drawTop += height;
this.firstItem++;
this.checkinTile(tiles.shift());
first = tiles[0];
}
// Collect up to targetBottom
var last = tiles[tiles.length - 1];
while(tiles.length &&
targetBottom < this.drawBottom - viewHeights[last.viewType]) {
var height = viewHeights[last.viewType];
this.drawBottom -= height;
this.checkinTile(tiles.pop());
last = tiles[tiles.length - 1];
}
// Layout up to targetTop
while (this.firstItem > 0 &&
targetTop < this.drawTop) {
var datum = data[this.firstItem - 1];
var type = this.viewType(datum);
var height = viewHeights[type];
this.drawTop -= height;
var tile = targetBottom < this.drawTop ?
new Tile(datum, null, viewType, -1) : // off-screen
this.checkoutTile(type, datum, this.drawTop);
this.firstItem--;
tiles.unshift(tile);
}
// Layout down to targetBottom
while (this.firstItem + tiles.length < data.length - 1 &&
targetBottom > this.drawBottom) {
var datum = data[this.firstItem + tiles.length];
var type = this.viewType(datum);
var height = viewHeights[type];
this.drawBottom += height;
var tile = targetTop > this.drawBottom ?
new Tile(datum, null, viewType, -1) : // off-screen
this.checkoutTile(type, datum, this.drawBottom - height);
tiles.push(tile);
}
// Debug validate:
// for (var i = 0; i < tiles.length; i++) {
// if (tiles[i].datum !== data[this.firstItem + i])
// throw Error('Invalid')
// }
}
// FIXME: Needs better name.
Tiler.prototype.updateFirstItem = function(offset) {
var tiles = this.tiles;
if (!tiles.length) {
this.firstItem = 0;
} else {
this.firstItem += offset;
}
}
Tiler.prototype.checkinAllTiles = function() {
var tiles = this.tiles;
while (tiles.length) {
this.checkinTile(tiles.pop());
}
}
Tiler.prototype.reset = function() {
this.checkinAllTiles();
this.drawTop = 0;
this.drawBottom = 0;
}
SkyElement({
name: 'city-list',
loader: null,
scroller: null,
tiler: null,
date: null,
month: null,
views: null,
attached: function() {
this.views = {};
this.loader = new Loader();
this.scroller = new Scroller();
this.tiler = new Tiler(
this.shadowRoot.getElementById('contentarea'), this.views, {
stateHeader: 27,
letterHeader: 18,
cityItem: 30
});
this.dataLoaded = this.dataLoaded.bind(this);
this.shadowRoot.getElementById('scroller')
.addEventListener('scroll', this.handleScroll.bind(this));
var self = this;
requestAnimationFrame(function() {
self.domReady();
self.loader.maybeLoadMoreData(self.dataLoaded);
});
},
domReady: function() {
this.scroller.setup(this.shadowRoot.getElementById('scroller'),
this.shadowRoot.getElementById('scrollarea'),
this.shadowRoot.getElementById('contentarea'));
var scrollFrame = this.scroller.getCurrentFrame();
this.tiler.setupViews(scrollFrame);
},
updateView: function(data, scrollChanged) {
var scrollFrame = this.scroller.getCurrentFrame();
this.tiler.drawTiles(scrollFrame, data);
var datum = scrollChanged ?
this.tiler.getFirstVisibleDatum(scrollFrame) : null;
this.loader.maybeLoadMoreData(this.dataLoaded, datum);
},
dataLoaded: function(data, indexOffset) {
var scrollFrame = this.scroller.getCurrentFrame();
this.tiler.updateFirstItem(indexOffset);
this.updateView(data.items, false);
},
handleScroll: function(event) {
if (!this.scroller.captureNewFrame(event))
return;
this.updateView(this.loader.getItems(), true);
}
});
})(this);
</script>
<!--
// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
-->
<script>
function StateHeader(state) {
this.state = state;
this.headerOrder = 1;
};
function LetterHeader(letter) {
this.letter = letter;
this.headerOrder = 2;
}
function CitySequence(cities)
{
this.items = [];
this.cursor = 0;
var lastState;
var lastLetter;
for (var i = 0; i < cities.length; i++) {
var city = cities[i];
if (!lastState || lastState.state != city.state) {
lastState = new StateHeader(city.state);
this.items.push(lastState);
lastLetter = undefined;
}
if (!lastLetter || lastLetter.letter != city.name[0]) {
lastLetter = new LetterHeader(city.name[0]);
this.items.push(lastLetter);
}
this.items.push(city);
}
};
CitySequence.prototype = {
append: function(other) {
var lastCity = this.items[this.items.length - 1];
var firstOtherCity = other.items[2];
var index = 0;
if (firstOtherCity.state == lastCity.state) {
// skip StateHeader
if (firstOtherCity.name[0] == lastCity.name[0]) {
// skip LetterHeader
index = 2;
} else {
index = 1;
}
}
for (; index < other.items.length; index++) {
this.items.push(other.items[index]);
}
}
};
module.exports = CitySequence;
</script>
<!--
// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
-->
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport"
content="initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=yes, width=device-width">
<link rel="import" href="city-list.sky" />
<style>
html, body {
margin: 0;
padding: 0;
font-family: "Roboto", "HelveticaNeue",sans-serif;
-webkit-font-smoothing: antialiased;
font-size: 13px;
color: #222;
width: 100%;
height: 100%;
-webkit-user-select: none;
}
</style>
</head>
<script>
window.startLoad = new Date().getTime();
</script>
<body>
<city-list></city-list>
</body>
</html>
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