Centering text in php image

Question

I'm not sure how I can center text in a php-created image using imagettftext. Here's my code:

header('Content-Type: image/png');
$im = imagecreatetruecolor(260, 180);
$background = imagecolorallocate($im, 0, 0, 255);
$white = imagecolorallocate($im, 255, 255, 255);
$grey = imagecolorallocate($im, 60, 153, 181);
$black = imagecolorallocate($im, 0, 0, 0);
imagefilledrectangle($im, 0, 0, 399, 200, $white);
$text = $_GET['tname'];
$font = 'OpenSans-Semibold.ttf';
imagettftext($im, 20, 0, $x+1, $y+1, $grey, $font, $text);
imagettftext($im, 20, 0, $x, $y, $black, $font, $text);
imagepng($im);
imagedestroy($im);

Answer 1

Here is a working example, based on imagetttfbbox:

$im = imagecreatetruecolor(200, 75);
$white = imagecolorallocate($im, 255, 255, 255);
$black = imagecolorallocate($im, 0, 0, 0);

// text, font and size to draw
$text = 'hello world';
$font = 'OpenSans-Semibold.ttf';
$size = 30;

// determine the size of the text so we can center it
$box = imagettfbbox($size, 0, $font, $text);
$text_width = abs($box[2]) - abs($box[0]);
$text_height = abs($box[5]) - abs($box[3]);
$image_width = imagesx($im);
$image_height = imagesy($im);
$x = ($image_width - $text_width) / 2;
$y = ($image_height + $text_height) / 2;

// add text
imagettftext($im, $size, 0, $x, $y, $white, $font, $text);

// set content type
header('Content-Type: image/png');

// output and destroy image
imagepng($im);
imagedestroy($im);