There's a bit of an annoyance with measuring font sizes and drawing boxes around text. When fonts are measured using ImageTTFbbox, the correct vertical height is returned. That is, the measurement of the phrase "Hanging" will be from the top of the "H" to the bottom of the "g".
The problem is that functions like imageTTFtext align with the "line" of the text - that is, in the phrase "Hanging", the alignment is below the "H", not the bottom of the "g". That means that if you draw a rectangle behind your text, it'll be incorrectly aligned because the hanging "g" will be outside the box.
For example, this doesn't work as you might expect (because the "g" hangs below the box):
<?php
$textbox = imageTTFBbox($size, 0, $font, 'Hanging');
$textwidth = abs($textbox[4] - $textbox[0]);
$textheight = abs($textbox[5] - $textbox[1]);
$colour = ImageColorAllocate($im, 100, 100, 100);
imagefilledrectangle($im, $x, $y - $textheight, $x + $textwidth, $y, $colour );
$black = ImageColorAllocate($im, 0, 0, 0);
ImageTTFText($image['resource'], $size, 0, $x, $y, $black, $font, 'Hanging');
?>
It also seems that the rectangle in the above example is located 1 pixel to the left of the text.
I haven't found a way to resolve this problem correctly. Instead, I have enlarged the rectangle and then put the text into it. I don't think this will work absolutely correctly for all fonts, so it's not exactly a perfect solution. However, it's better than nothing! Here is a snippet of it:
<?php
$enlargex = $textwidth * 0.08;
$enlargey = $textheight * 0.1;
$enlargey2 = $textheight * 0.5;
$colour = ImageColorAllocate($im, 100, 100, 100);
imagefilledrectangle($im, $x - $enlargex, $y - $textheight - $enlargey, $x + $textwidth + $enlargex, $y + $enlarge2, $colour );
?>
