Adding some more information along with a code-snippet

t1lib version: 1.3.1
Apache version: 1.3.27

The font can be fetched from the location in the main-comment.

When running the code, notice that G and Q does render differently from the rest of the characters.

----------[Code starts]-------------

$font_1 = imagepsloadfont('./AkzGBS20.pfb');

define('ANTIALIAS_MEDIUM',16);

$text = 'abcdefghijklmnopqrstuvxyz';

$x = 15;
$size = 12;
$y = 0;
$space = 0;
$tight = 0;
$angle = 0;
$antialias = ANTIALIAS_MEDIUM;

$text = strtoupper($text.'');

list($lx,$ly,$rx,$ry) = imagepsbbox($text,$font_1,$size,$space,$tight,$angle);
$w = $rx + 30;
$h = 18;
$y = 12;

$img = imagecreate($w,$h);
$fg_color = imagecolorallocate($img,133,118,98);
$bg_color = imagecolorallocate($img,255,255,255);

imagefill($img,2,2,$bg_color);
imagepstext($img,$text,$font_1,$size,$fg_color,$bg_color,$x,$y,$space,$tight,$angle,$antialias);
imagepng('test.png');
imagedestroy($img);
echo '<img src=test.png><br>';

--------------[Code ends]------------

Also, I should say, PHP 4.2.3 had to be patched with this patch in order to install correctly:
http://www.boutell.com/gd/php-4.2.3-gd-2.0.8.patch

I have looked in this patch, and it does not seem to include any fixes about my problem.

Here is an image that was produced with your sample script using latest stable PHP & bundled GD (with your font).
As far as I can tell the text is perfect.
http://bb.prohost.org/test2.png

Try generating an image with font size 12, and you might get the same results as me. The font renders well in some sizes (i've been testing 11 and 13 and higher).

I found a solution for this problem, when tampering with ext/gd/gd.c

I don't have the original line numbers available, because of some tampering. But it is not hard to find it.

In the php-function imagepstext, there is a codesnippet that looks like this:

--------[code starts]-----

for (i = 1; i < str_len; i++) {
                amount_kern = (int) T1_GetKerning(*f_ind, str[i-1], str[i]);
                amount_kern += str[i-1] == ' ' ? space : 0;
                add_width = (int) (amount_kern+width)/extend;

                char_path = T1_GetMoveOutline(*f_ind, add_width, 0, 0, size, transform);
                str_path = T1_ConcatOutlines(str_path, char_path);

                char_path = T1_GetCharOutline(*f_ind, str[i], size, transform);
                str_path = T1_ConcatOutlines(str_path, char_path);
        }
        str_img = T1_AAFillOutline(str_path, 0);

-----[code ends]-------

if you instead make this like it WAS in <=php4.2, it should look like this:

----[code starts]----
if (width) // this is the change
{
for (i = 1; i < str_len; i++) {
                amount_kern = (int) T1_GetKerning(*f_ind, str[i-1], str[i]);
                amount_kern += str[i-1] == ' ' ? space : 0;
                add_width = (int) (amount_kern+width)/extend;

                char_path = T1_GetMoveOutline(*f_ind, add_width, 0, 0, size, transform);
                str_path = T1_ConcatOutlines(str_path, char_path);

                char_path = T1_GetCharOutline(*f_ind, str[i], size, transform);
                str_path = T1_ConcatOutlines(str_path, char_path);
        }
        str_img = T1_AAFillOutline(str_path, 0);

}
else // change continues here
{
      str_img = T1_AASetString(*f_ind, str,  str_len, space, T1_KERNING, size, transform);
}

----[code ends]----

Then the problem went away (until you set the space-property to a non-zero value). So, evidentually, there is some kind of bug, or PHP handles spaced texts differently than t1lib does as standard.

For further releases, can you _please_ put the "if (width)"-statement as it was before?

The syntax seems to be uncorrect about the "space"-variable. This might be called "width".

This bug has been fixed in CVS.

In case this was a PHP problem, snapshots of the sources are packaged
every three hours; this change will be in the next snapshot. You can
grab the snapshot at http://snaps.php.net/.
 
In case this was a documentation problem, the fix will show up soon at
http://www.php.net/manual/.

In case this was a PHP.net website problem, the change will show
up on the PHP.net site and on the mirror sites in short time.
 
Thank you for the report, and for helping us make PHP better.