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!

TABLE OF CONTENTS

Download & Notes

Text on Image

Extras

The End

EXAMPLE CODE DOWNLOAD

Source code on GitHub Gist

Just click on “download zip” or do a git clone. I have released it under the MIT license, so feel free to build on top of it or use it in your own project.

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TUTORIAL VIDEO

EXAMPLE 1) SIMPLE WRITE TEXT ON IMAGE

<?php
// (A) OPEN IMAGE
$img = imagecreatefrompng("demo.png");

// (B) WRITE TEXT
$txt = "BUBBLE TEA";
$fontFile = "C:\Windows\Fonts\arial.ttf"; // CHANGE TO YOUR OWN!
$fontSize = 24;
$fontColor = imagecolorallocate($img, 255, 0, 0);
$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/png");
imagepng($img);
imagedestroy($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 = imagecreatefrompng("demo.png");

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

• 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 = "珍珠奶茶";
$txt = mb_convert_encoding($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 - WRITE TEXT TO IMAGE
}

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

• GD & Image Functions – PHP
• AJAX Image Upload In PHP – Code Boxx
• Write Multi-Line Text On Image In PHP – Code Boxx
• If you are looking for some fonts to use – Check out Font Squirrel.