用CSS3 Region和3D變換實現書籍翻頁效果
前言:我曾在之前的分享里提到CSS3 Region(區域模塊)的重要作用:實現更復雜的排版效果,實現更豐富的富文本體驗。下文就是和此模塊相關的實際應用,可以看到未來它將發揮出巨大的作用。

這一天終于到來:你開始對大段滾動的文字感到厭倦,并正在尋找一種新的格式,更加優雅,更加緊湊。它可以把長長的滾動條切分為整齊的頁面并結合在一起。我把這個發明叫做“書”。
利用CSS3 Region(去CanIUse看看當前瀏覽器支持的情況,Chrome需要進入chrome://flags并激活CSS3 Region)和3D變換,我們終于可以在現代瀏覽器上實現先進的書籍效果。所有你需要的僅是幾行JavaScript和一堆CSS。

讓我們開始定義書籍結構。這本書由書頁組成,而書頁包括兩面。每一面寫滿這本書的內容:
<div class="book">
<div> <!-- first page -->
<div> <!-- front cover -->
<h1>My Fancy Book</h1>
</div>
<div> <!-- backside of cover -->
<h1>By Me I. Myself</h1>
<h2>2012 Bogus HTML Publishing Ltd</h2>
</div>
</div>
<!-- content pages -->
<div>
<!-- front side of page -->
<div class="book-pages"></div>
<!-- back side of page -->
<div class="book-pages"></div>
</div>
<div>
<div class="book-pages"></div>
<div class="book-pages"></div>
</div>
<div>
<div class="book-pages"></div>
<div class="book-pages"></div>
</div>
</div>
我們將使用CSS Region控制文字流入書頁。但是我們需要先定義這本書的內容。
<span id="book-content"> blah blah blah ... </span>
現在書已經寫完了,讓我們開始定義CSS流。我使用“+”字符作為占位符替換-webkit或-moz這樣的瀏覽器前綴:
#book-content {
+flow-into: book-text-flow;
}
.book-pages {
+flow-from: book-text-flow;
}
現在來自span#book-content的內容會轉而顯示到div.book-pages元素里。這本書現在看起來相當差勁。為了讓它看起來更美,我們需要更多努力。
我們可能需要把HTML的結構轉換為更類似于書籍的形式:
html {
width: 100%;
height: 100%;
}
body {
/* The entire body is clickable area. Let the visitor know that. */
cursor: pointer;
width: 100%;
height: 100%;
/* Set the perspective transform for the page so that our book looks 3D. */
+perspective: 800px;
/* Use 3D for body, the book itself and the page containers. */
+transform-style: preserve-3d;
}
.book {
+transform-style: preserve-3d;
position: absolute;
}
/* Page containers, contain the two sides of the page as children. */
.book > div {
+transform-style: preserve-3d;
position: absolute;
}
/* Both sides of a page. These are flat inside the page container, so no preserve-3d. */
.book > div > div {
/* Fake some lighting with a gradient. */
background: +linear-gradient(-45deg, #ffffff 0%, #e5e5e5 100%);
width: 600px;
height: 400px;
overflow: hidden;
/* Pad the page text a bit. */
padding: 30px;
padding-bottom: 80px;
}
/* Front of a page */
.book > div > div:first-child {
/* The front side of a page should be slightly above the back of the page. */
+transform: translate3d(0px, 0px, 0.02px);
/* Add some extra padding for the gutter. */
padding-left: 40px;
/* Stylish border in the gutter for visual effect. */
border-left: 2px solid #000;
}
/* Back of a page */
.book > div > div:last-child {
/* The back side of a page is flipped. */
+transform: rotateY(180deg);
padding-right: 40px;
border-right: 2px solid #000;
}
/* Front cover of the book */
.book > div:first-child > div:first-child {
/* The covers have a different color. */
background: +linear-gradient(-45deg, #8c9ccc 0%, #080f40 100%);
/* Put a border around the cover to make it cover the pages. */
border: 2px solid #000;
/* And center the cover. */
margin-left: -1px;
margin-top: -1px;
}
/* Back cover of the book */
.book > div:last-child > div:last-child {
background: +linear-gradient(-45deg, #8c9ccc 0%, #080f40 100%);
border: 2px solid #000;
margin-left: -1px;
margin-top: -1px;
}
我們完成了書籍風格的HTML頁面,下面要開始添加JS。 我們必須要給這本平平的書一些合適的體積。為了增加體積,我們在Z軸上定位每一頁。
(function() {
var books = document.querySelectorAll('.book');
for (var i = 0; i < books.length; i++) {
var book = books[i];
var pages = book.childNodes;
for (var j = 0; j < pages.length; j++) {
if (pages[j].tagName == "DIV") {
setTransform(pages[j], 'translate3d(0px, 0px, ' + (-j) + 'px)');
}
}
}
})();
下面的代碼使我們的書頁平滑的顯示。
.book > div {
+transition: 1s ease-in-out;
}
最后,為了自動翻頁,我們需要綁定事件。
(function(){
// Get all the pages.
var pages = document.querySelectorAll('.book > div');
var currentPage = 0;
// Go to previous page when clicking on left side of window.
// Go to the next page when clicking on the right side.
window.onclick = function(ev) {
if (ev.clientX < window.innerWidth/2) {
previousPage();
} else {
nextPage();
}
ev.preventDefault();
};
var previousPage = function() {
if (currentPage > 0) {
currentPage--;
// Rotate the page to closed position and move it to its place in the closed page stack.
setTransform(pages[currentPage], 'translate3d(0px,0px,' + (-currentPage) + 'px) rotateY(0deg)');
}
};
var nextPage = function() {
if (currentPage < pages.length) {
// Rotate the page to open position and move it to its place in the opened stack.
setTransform(pages[currentPage], 'translate3d(0px,0px,' + currentPage + 'px) rotateY(-150deg)');
currentPage++;
}
};
})();
最終,我們完成了這本“書”。
你可以在這里看到示例以及源代碼。如果你的瀏覽器不支持CSS Region,這本書會慘不忍睹,此時你可以試試這個例子 。

譯自:http://updates.html5rocks.com/2012/07/Writing-a-flippable-book-using-CSS-Regions-and-3D-transforms
轉載請注明:來自蔣宇捷的博客(http://blog.csdn.net/hfahe)