请教：php图像识别，怎么讲拍的证件照片缩放到实际大小然后打印？

[平步江湖]

需要把照片中的证件照片缩放到实际大小，打印出来，A4纸打印出来的照片跟实际大小一致，这个要怎么做？

[Joshua Burgin]

<?php // 重置图片文件大小 function resize_image($filename, $tmpname, $xmax, $ymax) {     $ext = explode(".", $filename);     $ext = $ext[count($ext)-1];     if($ext == "jpg" || $ext == "jpeg")         $im = imagecreatefromjpeg($tmpname);     elseif($ext == "png")         $im = imagecreatefrompng($tmpname);     elseif($ext == "gif")         $im = imagecreatefromgif($tmpname);     $x = imagesx($im);     $y = imagesy($im);     if($x <= $xmax && $y <= $ymax)         return $im;     if($x >= $y) {         $newx = $xmax;         $newy = $newx * $y / $x;     }     else {         $newy = $ymax;         $newx = $x / $y * $newy;     }     $im2 = imagecreatetruecolor($newx, $newy);     imagecopyresized($im2, $im, 0, 0, 0, 0, floor($newx), floor($newy), $x, $y);     return $im2; } ?>