January 2021
Intermediate to advanced
505 pages
9h 45m
Chinese
Content preview from PHP编程：第4版
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
文本
｜
275
页眉、页脚和类扩展
至此，我们仅看到了在
PDF
页面上输出的少量东西。这只是有目的地向你展示，在一个
受控环境下可以做什么，现在我们需要扩展这个库。记住，这个库实际上仅是一个让你
使用和扩展的类定义。我们现在看该段声明的第二部分——类的扩展。
FPDF
的确只是
一个类定义，要扩展它，可以用
PHP
内建的对象指令，像下面这样
：
class MyPDF extends FPDF
我们在这里借助
FPDF
类并且将它扩展为
MyPDF
。然后，可以在这个对象上扩展任何方法。
甚至可以给我们的扩展类添加更多你想要的方法，但过一会儿再做。我们要看的前两个
方法是在
FPDF
父类定义的空方法 ：
header()
和
footer()
，如名字所示，它们是用来为
PDF
文件中的每个页面生成页眉和页脚的。示例
11-5
有点长，其实只使用了很少的新方
法 ；最重要的是调用了
aliasNbPages()
方法，它是在将
PDF
文件发送到浏览器前跟踪
的总页数。
示例 11-5：定义页眉和页脚的方法
<?php
require("../fpdf/fpdf.php");
class MyPDF extends FPDF
{
function header()
{
global $title;
$this->setFont("Times", '', 12);
$this->setDrawColor(0, 0, 180);
$this->setFillColor(230, 0, 230);
$this->setTextColor(0, ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.