PHP GD给出了错误

Update: TTF file seems to be there after testing. Update: changed to a relative path for the font file. Still doesn't work.

I get the following error when I try to make an image using GD through PHP.

[Tue Sep 01 19:44:15 2009] [error] [client IP ADDRESS] PHP Warning: imagettftext() [function.imagettftext]: Could not find/open font in /www/vhosts/website.com/htdocs/trial/TextToImage.class.php on line 38

I changed the path for the font as it was giving me the same error. I added the font to the server by dropping the file into the folder. What am I missing?

/**
 * @name                    : makeImageF
 *
 * Function for create image from text with selected font.
 *
 * @param String $text     : String to convert into the Image.
 * @param String $font     : Font name of the text.
 * @param int    $W        : Width of the Image.
 * @param int    $H        : Hight of the Image.
 * @param int     $X        : x-coordinate of the text into the image.
 * @param int    $Y        : y-coordinate of the text into the image.
 * @param int    $fsize    : Font size of text.
 * @param array  $color       : RGB color array for text color.
 * @param array  $bgcolor  : RGB color array for background.
 *
 */
public function makeImageF($text, $font="/www/vhosts/website.com/htdocs/trial/CENTURY.TTF", $W=200, $H=20, $X=0, $Y=0, $fsize=18, $color=array(0x0,0x0,0x0), $bgcolor=array(0xFF,0xFF,0xFF)){

    $this->im = @imagecreate($W, $H)
        or die("Cannot Initialize new GD image stream");

    $background_color = imagecolorallocate($this->im, $bgcolor[0], $bgcolor[1], $bgcolor[2]);        //RGB color background.
    $text_color = imagecolorallocate($this->im, $color[0], $color[1], $color[2]);            //RGB color text.

    imagettftext($this->im, $fsize, $X, $Y, $fsize, $text_color, $font, $text);
}

It's probably a font file in a format unknown to your version of libgd.
The gd section of the output of phpinfo() should include version of the FreeType/T1Lib library. Which one is it?
And what does

echo '<pre>Debug: '; passthru('file '.$font); echo "</pre>
";
// imagettftext($this->im, $fsize, $X, $Y, $fsize, $text_color, $font, $text);

print?

Edit: oops, forget about the the type of the font file. The error for that would be Could not read font. Could not find/open font really means what it says: either there is no such file or it cannot be accessed.
The output of passthru('file '.$font); is "only" CENTURY.TTF: TrueType font data? Then you've used a relative path. Try passing an absolute path to imagettftext()

$font_realpath = realpath($font);
if ( !$font_realpath || !is_file($font_realpath) ) {
  die 'no such font file';
}
else if ( !is_readable($font_realpath) ) {
  die 'cannot read font file';
}
imagettftext($this->im, $fsize, $X, $Y, $fsize, $text_color, $font_realpath, $text);

It may be the way you are calling the function - add this to the function to help you further

if (!file_exists($font))
    die("Font not found ($font)");
if (!is_readable($font))
    die("Font exists but not readable ($font)");

Also check the font path is absolute and doesn't start with a slash, the manual page for imagettftext states

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.

Does the web server (the user that runs the web server) have read access to that folder/file?