How To Add Text To Images In PHP (Simple Examples)

Welcome to a tutorial on how to add text to images in PHP. Need to add a watermark or copyright message on uploaded images on a PHP server?

It’s that simple. But let us walk through more examples, along with a simple tip to center the text on the image – Read on!

ⓘ I have included a zip file with all the example source code at the start of this tutorial, so you don’t have to copy-paste everything. Or if you just want to dive straight in.

 

 

QUICK SLIDES

 

TABLE OF CONTENTS

Download & Notes	Text on Image	Useful Bits & Links
Tutorial Video	The End

 

 

QUICK NOTES

• Please enable the GD extension extension=gd (or gd2 prior to PHP8) in the php.ini file.
• In all the scripts, please change the font file $fontFile to your own.
• Also, make sure that PHP can access the font file.

If you spot a bug, feel free to comment below. I try to answer short questions too, but it is one person versus the entire world… If you need answers urgently, please check out my list of websites to get help with programming.

 

EXAMPLE CODE DOWNLOAD

Click here to download all the example source code in a zip file – I have released it under the MIT License, so feel free to build on top of it if you want to.

 

 

 

EXAMPLE 1) SIMPLE WRITE TEXT ON IMAGE

<?php
// (A) OPEN IMAGE
$img = imagecreatefromjpeg("balloon.jpg");

// (B) WRITE TEXT
$txt = "Hello World";
$fontFile = "C:\Windows\Fonts\arial.ttf"; // CHANGE TO YOUR OWN!
$fontSize = 24;
$fontColor = imagecolorallocate($img, 255, 255, 255);
$posX = 5;
$posY = 24;
$angle = 0;
imagettftext($img, $fontSize, $angle, $posX, $posY, $fontColor, $fontFile, $txt);

// (C) OUTPUT IMAGE
// (C1) DIRECTLY SHOW IMAGE
header("Content-type: image/jpeg");
imagejpeg($img);
imagedestroy($img);

// (C2) OR SAVE TO A FILE
// $quality = 100; // 0 to 100
// imagejpeg($img, "demo.jpg", $quality);

This is pretty much the “expanded version” of the introduction snippet, as straightforward as can be.

1. Load the image into an object with imagecreatefromjpeg().
2. Write text using imagettftext().
3. Output the image – Directly show it in the browser, save it into a file, save into the database, email it as an attachment, do whatever is required.

 

 

EXAMPLE 2) CENTER TEXT IN IMAGE

<?php
// (A) OPEN IMAGE
$img = imagecreatefromjpeg("balloon.jpg");

// (B) TEXT & FONT SETTINGS
$txt = "Hello World";
$fontFile = "C:\Windows\Fonts\arial.ttf"; // CHANGE TO YOUR OWN!
$fontSize = 24;
$fontColor = imagecolorallocate($img, 255, 255, 255);
$angle = 0;

// (C) CALCULATE TEXT BOX POSITION
// (C1) GET IMAGE DIMENSIONS
$iWidth = imagesx($img);
$iHeight = imagesy($img);

// (C2) GET TEXT BOX DIMENSIONS
$tSize = imagettfbbox($fontSize, $angle, $fontFile, $txt);
$tWidth = max([$tSize[2], $tSize[4]]) - min([$tSize[0], $tSize[6]]);
$tHeight = max([$tSize[5], $tSize[7]]) - min([$tSize[1], $tSize[3]]);

// (C3) CENTER THE TEXT BLOCK
$centerX = CEIL(($iWidth - $tWidth) / 2);
$centerX = $centerX<0 ? 0 : $centerX;
$centerY = CEIL(($iHeight - $tHeight) / 2);
$centerY = $centerY<0 ? 0 : $centerY;

// (D) DRAW TEXT ON IMAGE
imagettftext($img, $fontSize, $angle, $centerX, $centerY, $fontColor, $fontFile, $txt);
 
// (E) OUTPUT IMAGE
header("Content-type: image/jpeg");
imagejpeg($img);
imagedestroy($img);

Yikes! This looks crazy, but the main bulk of this script is calculating the position of the text box. If you want to be a happy person, just skip and use this as-it-is… If not, here’s how the calculations work:

(C1) Self-explanatory. Get the image width with imagesx() and height with imagesy().

(C2) To calculate the dimensions of the text box, we have to use imagettfbbox(). This returns an array with 8 numbers, which are the coordinates of the text box.

Key	Position
0	lower-left corner, X position
1	lower-left corner, Y position
2	lower right corner, X position
3	lower right corner, Y position
4	upper right corner, X position
5	upper right corner, Y position
6	upper left corner, X position
7	upper left corner, Y position

• For the width of the text box, we take the right-most point (2 or 4) minus the left-most point (0 or 6).
• For the height of the text box, we take the top-most point (5 or 7) minus the bottom-most point (1 or 3).

(C3) Lastly, we can calculate the center X and Y positions.

• Center X = (width of image – width of text box) / 2.
• Center Y = (height of image – height of text box) / 2.

 

 

EXAMPLE 3) NON-ENGLISH UTF-8 ENCODING

<?php
// (B) UTF-8 TEXT
// https://stackoverflow.com/questions/9458317/working-with-gd-imagettftext-and-utf-8-characters
$txt = "世界你好";
$txt = mb_convert_encoding($txt, "HTML-ENTITIES", "UTF-8");
$txt = preg_replace('~^(&([a-zA-Z0-9]);)~', htmlentities('${1}'), $txt);

If you are working with non-English languages, GD is not exactly the friendliest. But all credits go to this post on StackOverflow – Just use a font for your required language and do a bit of manual UTF-8 encoding.

 

 

 

ADDING TEXT TO PICTURES IN FOLDER

<?php
$files = glob("FOLDER/*.{jpg,jpeg}", GLOB_BRACE);
foreach ($files as $f) {
  $img = imagecreatefromjpeg($f);
  // SAME AS ABOVE
}

Just get all the images in the folder and loop through all of them.

 

FONT COPYRIGHT

You can specify which font to use, but please do not go on a download frenzy and start using every font you find on the Internet. There is a hidden nightmare behind fonts, and it is called copyright. Yes, some fonts are subjected to copyright, and you can get bitten by the law monster if you make money off edited images… Always check the usage license of the “free fonts”.

 

REFERENCES & LINKS

• Here is the official PHP GD reference for you guys who want to learn more.
• This tutorial only covered how to add text, but did not go into uploading the image files – Check out my other guide on how to upload images with AJAX if you want.
• If you are looking for some fonts to use – Check out Font Squirrel.

 

TUTORIAL VIDEO

 

INFOGRAPHIC CHEAT SHEET