PHP Manual: Give the bounding box of a text using TrueType fonts

Description

arrayfalse imagettfbbox(
    float $size,
    float $angle,
    string $font_filename,
    string $string,
    array $options = []
)

This function calculates and returns the bounding box in pixels for a TrueType text.

Note:
Prior to PHP 8.0.0, imageftbbox was an extended variant of imagettfbbox which additionally supported the extrainfo. As of PHP 8.0.0, imagettfbbox is an alias of imageftbbox.

Parameters

size

The font size in points.

angle

Angle in degrees in which string will be measured.

fontfile

The path to the TrueType font you wish to use.

Depending on which version of the GD library PHP is using, when fontfile does not begin with a leading / then .ttf will be appended to the filename and the library will attempt to search for that filename along a library-defined font path.

When using versions of the GD library lower than 2.0.18, a space character, rather than a semicolon, was used as the 'path separator' for different font files. Unintentional use of this feature will result in the warning message: Warning: Could not find/open font. For these affected versions, the only solution is moving the font to a path which does not contain spaces.

In many cases where a font resides in the same directory as the script using it the following trick will alleviate any include problems.

<?php
// Set the environment variable for GD
putenv('GDFONTPATH=' . realpath('.'));

// Name the font to be used (note the lack of the .ttf extension)
$font = 'SomeFont';
?>

Note:
Note that open_basedir does not apply to fontfile.

string

The string to be measured.

options

Same as in imagettftext.

Return Values

imagettfbbox returns an array with 8 elements representing four points making the bounding box of the text on success and false on error.

key	contents
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

The points are relative to the text regardless of the angle, so "upper left" means in the top left-hand corner seeing the text horizontally.

Changelog

Version	Description
8.0.0	The `options` has been added.

Examples

Example #1 imagettfbbox example

<?php
// Create a 300x150 image
$im = imagecreatetruecolor(300, 150);
$black = imagecolorallocate($im, 0, 0, 0);
$white = imagecolorallocate($im, 255, 255, 255);

// Set the background to be white
imagefilledrectangle($im, 0, 0, 299, 299, $white);

// Path to our font file
$font = './arial.ttf';

// First we create our bounding box for the first text
$bbox = imagettfbbox(10, 45, $font, 'Powered by PHP ' . phpversion());

// This is our cordinates for X and Y
$x = $bbox[0] + (imagesx($im) / 2) - ($bbox[4] / 2) - 25;
$y = $bbox[1] + (imagesy($im) / 2) - ($bbox[5] / 2) - 5;

// Write it
imagettftext($im, 10, 45, $x, $y, $black, $font, 'Powered by PHP ' . phpversion());

// Create the next bounding box for the second text
$bbox = imagettfbbox(10, 45, $font, 'and Zend Engine ' . zend_version());

// Set the cordinates so its next to the first text
$x = $bbox[0] + (imagesx($im) / 2) - ($bbox[4] / 2) + 10;
$y = $bbox[1] + (imagesy($im) / 2) - ($bbox[5] / 2) - 5;

// Write it
imagettftext($im, 10, 45, $x, $y, $black, $font, 'and Zend Engine ' . zend_version());

// Output to browser
header('Content-Type: image/png');

imagepng($im);
?>

Notes

Note: This function is only available if PHP is compiled with freetype support (--with-freetype-dir=DIR)

imagettfbbox