Do it like this. Remember to place the font file "arial.ttf" in current directory:
<?php
// Create a 650x150 image and create two colors
$im = imagecreatetruecolor(650, 150);
$white = imagecolorallocate($im, 255, 255, 255);
$black = imagecolorallocate($im, 0, 0, 0);
// Set the background to be white
imagefilledrectangle($im, 0, 0, 649, 149, $white);
// Path to our font file
$font = './arial.ttf';
//test it out
for($i=2;$i<10;$i++)
WriteTextForMe($im, $font, str_repeat($i, $i), -140 + ($i*80), 70 + rand(-30, 30), -160 + (($i+1)*80), 150, $black);
//this function does the magic
function WriteTextForMe($im, $font, $text, $x1, $y1, $x2, $y2, $allocatedcolor)
{
//draw bars
imagesetthickness($im, 2);
imagerectangle($im, $x1, $y1, $x2, $y2, imagecolorallocate($im, 100,100,100));
//draw text with dynamic stretching
$maxwidth = $x2 - $x1;
for($size = 1; true; $size+=1)
{
$bbox = imagettfbbox($size, 0, $font, $text);
$width = $bbox[2] - $bbox[0];
if($width - $maxwidth > 0)
{
$drawsize = $size - 1;
$drawX = $x1 + $lastdifference / 2;
break;
}
$lastdifference = $maxwidth - $width;
}
$size--;
imagettftext($im, $drawsize, 0, $drawX, $y1 - 2, $allocatedcolor, $font, $text);
}
// Output to browser
header('Content-type: image/png');
imagepng($im);
imagedestroy($im);
?>
It uses imagettfbbox
function to get width of the text, then loops over the font size to get correct size, centers it and displays it.
So, it outputs the following:
![alt text](http://i.imgur.com/6kLA1.png)