Calculate string width using some font.

Hey list! :) I've got a problem trying to calculate a string width using an X font with some Y font size to use in an svg-to-pdf conversion. This is what I try to do: 1. Create a dummy image. 2. Set the text there using font X and the font size Y (it seems that when I create the image it renders it at 72dpi so I need to reduce it at 300dpi) I'm not sure what the imagettftext() function returns, are those values measured in pixels ? I read in some page that the proportion to reduce the image at 300dpi is reduce the size to 24% of its original size. http://www.printingforless.com/resolution.html That's the code: *** // Create dummy image. $rsc_image = imagecreate( 1, 1 ); // Set image. $arr_ftx = imagettftext( $rsc_image, $int_font_size, 0, 0, 0, -1, "./fonts/{$str_font_file}", $str_variable_value ); // Destroy dummy image. imagedestroy( $rsc_image ); // Set structure of widths. // TODO: Magik numbers. $arr_variable_pixels[$str_variable_index] = ( ( $arr_ftx[2] * 24 ) / 100 ); *** Thx for any help.