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How to Generate a PDF File in PHP

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Difficulty:BeginnerLength:LongLanguages:

In this article, we’re going to discuss how you can generate PDF files in PHP. We'll use the TCPDF library to create PDF documents programmatically.

If you’re working on a website which allows users to download or print documents like order receipts, bills, or invoices, you have a couple of options. You can either display the document inline in the browser or provide a download. When it comes to downloading documents, PDF is one of the best formats and is excellent at preserving text formatting.

So if you want to learn how to generate PDF files on your PHP website, you’re in the right place!

How to Install the TCPDF Library

In this section, we’ll see how to install the TCPDF library.

There are different ways to install the TCPDF library on your server. The TCPDF library is available at Packagist and GitHub, so you could either use Composer or clone it from GitHub. In our case, we’re going to install it with Composer.

Go ahead and run the following command to install the TCPDF library with Composer.

Once it’s installed successfully, you need to include the autoload.php file in your PHP script, as shown in the following snippet.

And with that, you’re ready to use all the utility methods provided by the TCPDF library.

How to Use the TCPDF Library

In this section, we’ll build a real-world example, which demonstrates how to generate a PDF invoice. The TCPDF library provides a lot of ready-made templates that you could use as a reference to generate PDF documents. However, we’re going to generate an invoice from scratch.

As I’ve already mentioned in the previous section, the TCPDF library provides a lot of ready-made templates that allow you to generate generic PDF files with headers and footers. And that’s really useful if you’re happy with the default formatting and settings. But if you want to customize the header and footer along with the content, you would have to extend the TCPDF class and override the corresponding methods.

In our example, we’ll create two files: customPdfGenerator.php and example.php. In the customPdfGenerator.php file, we’ll create the CustomPdfGenerator class, which will extend the core TCPDF class and override a couple of methods. In the example.php file, we’ll see how to use the CustomPdfGenerator class.

The CustomPdfGenerator Class

Go ahead and create the customPdfGenerator.php file with the following contents.

The important thing to note is that the CustomPdfGenerator class extends the TCPDF class, so we can use all the utility methods provided by the TCPDF class to format and generate PDF documents.

The sole purpose of creating our own class instead of directly using the TCPDF class is that we don’t want to use built-in header and footer components. And thus, we’ve overridden the header and footer methods in our class.

The Header Method

In the header, we want to display a company logo along with the owner's name. Let's go through the header method to understand how it works.

Firstly, we've used the Image method to draw a company logo on the left side. It’s important that you need to pass an absolute path of the logo image to the Image method. Next, we’ve used the SetFont method to set the font-family and font-size of the text, which will be added in the header. Finally, we’ve used the Cell method to print the owner name on the right-hand side.

You'll notice that there are a lot of arguments that you could pass in these methods, and I would encourage you to explore them in detail since it’s not possible to discuss each and every argument in this article.

With the above setup, the header would look like this:

Header

The Footer Method

In the footer, we want to display some static text, so the Footer method is pretty straightforward, as shown in the following snippet.

The footer section would look like this:

Footer

Finally, there’s the printTable method, and we’ll get back to this later. The printTable method is not related to the TCPDF class. Instead, it’s our custom utility method, which we’ll use to draw the table to display the item information.

So that’s the CustomPdfGenerator class. In the next section, we’ll see how to use it along with a handful of other methods to generate a complete PDF invoice!

The example.php File

In the previous section, we’ve created the CustomPdfGenerator wrapper class, which we can use to generate PDF files with custom headers and footers. In this section, we’ll demonstrate how you can use it.

Go ahead and create the example.php file with the following contents.

Let’s go through the important snippets in the above file.

Firstly, we’ve included the autoload.php file to make sure that the TCPDF class is autoloaded. Next, we’ve included the customPdfGenerator.php file to load our custom class.

Next, we’ve instantiated the CustomPdfGenerator class along with the default settings. We’ve also called a couple of methods to do the default setup before we actually start writing into the PDF file.

The constants that we’ve used in the above snippet are already defined in the tcpdf_autoconfig.php file. To override one of these constants, you just need to define it in your script, and the TCPDF library will use your values. For example, the default value of the PDF_PAGE_ORIENTATION constant is P (portrait), and if you want to change it to L (landscape), you just need to include define ('PDF_PAGE_ORIENTATION', 'L'); in your script.

Next, there’s an important snippet which calls the AddPage method, which actually adds a new page in the PDF document.

So we’ve added a page now, and we could start writing on this page.

Next, we’ve used the Write and writeHTML methods to print the date and invoice number on the left side.

The Write method prints text from the current position, and you can use it to print plain text. On the other hand, the writeHTML method allows you to preserve HTML formatting in the text. Although the writeHTML method provides limited HTML formatting support, it covers all the HTML tags that are used frequently in day-to-day development.

Similarly, we’ve printed the address and bill-to address with the help of the writeHTML method.

By default, the writeHTML method prints text on the left side. If you want to print right-aligned text, you can pass R as the last argument of the writeHTML method, as shown in the above snippet. In our case, we want to display the bill-to address aligned right.

Let’s quickly look at what we’ve built so far.

Address

Next, we have a snippet which does the heavy lifting of printing the item information table.

Remember the printTable method which we defined in the customPdfGenerator.php class? Now it’s time to explore it in detail. Let’s pull in the code of the printTable method.

First, we called a couple of methods to set the font size, fill color, line width, and text color before we actually start printing the header row of the invoice table. Next, we loop through the $header array and print table header titles with the help of the Cell method.

The Cell method allows you to print a cell (rectangular area) with optional borders, background color, and character string. You could also specify the alignment of the text which is printed in the cell. And thus, the Cell method is a perfect candidate to build a table.

After we print the table header titles, we loop through the $data array and print it to complete the whole table. Finally, we’ve called the Cell method a couple of times to print the total amount.

A quick preview of the table should look like this:

Item Information Table

Now, let’s get back to the example.php file to go through the last few lines of code.

At the end of the invoice, we’ll print a few comments and contact information as shown in the following snippet.

Finally, we’ve used the Output method to save the PDF file to the disk. If you don’t want to save the PDF file on the disk, and instead want to just send it to the browser, you would need to use I in the second argument of the Output method.

Go ahead and run the example.php file, and it should generate the PDF file as shown in the following screenshot.

Full Preview

Conclusion

So that’s how you can use the TCPDF library to create PDF documents in PHP.  We created a real-world example to demonstrate some of the different APIs provided by the TCPDF library.

The TCPDF official documentation provides a lot of ready-made templates that you could explore to understand the built-in APIs, and I would encourage you to explore it!

If you want to learn more about including PDFs in your site, check out the links below:

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