PHP 이미지 워터마크 기능

<?php
/**
 * 功能：给一张图片加上水印效果
 *      $i 要加水印效果的图片
 *      $t 水印文字
 *      $size 文字大小
 *      $pos 水印的位置
 *      $color 文字的颜色
 *      $flag 是布尔值，主要用来区分是不是原图上加水印
 *      $type 如果$flag等于false 则新图上加上水印 新文件名为 原名_txt.jpg
 */
function txt($i,$t=&#39;版权所有&#39;,$size=25,$pos=5,$color=&#39;rand&#39;,$flag=true,$type=&#39;_txt&#39;){
  $img = imagecreatefromjpeg($i);
  $w = imagesx($img);
  $h = imagesy($img);
  $font = dirname(__FILE__).&#39;/font/ls.ttf&#39;;
  $ps = imagettfbbox($size,0,$font,$t);
  $tw = $ps[4];
  $th = abs($ps[5]);
  switch($pos){
    case 1:break;  
    case 2:break;  
    case 3:break;  
    case 4:break;  
    case 5:$x=($w-$tw)/2;$y=($h-$th)/2+$th;break;  
    case 6:break;  
    case 7:break;  
    case 8:break;  
    case 9:break;  
    default:break;
  }
  $c = getcolor($img,$color);
  imagettftext($img,$size,0,$x,$y,$c,$font,$t);
  if($flag){
    imagejpeg($img,$i); 
  }else{
    $ext = ext($i);
    $ppp = rtrim($i,&#39;.&#39;.$ext);
    $ppp = $ppp.$type.&#39;.&#39;.$ext;
    imagejpeg($img,$ppp);
  }
}
 
function getcolor($i,$c=&#39;rand&#39;,$a=50){
  $cc = &#39;&#39;;
  switch($c){
    case &#39;white&#39;:$cc=imagecolorallocatealpha($i,255,255,255,$a);break;
    case &#39;black&#39;:$cc=imagecolorallocatealpha($i,0,0,0,$a);break;
    case &#39;red&#39;:$cc=imagecolorallocatealpha($i,255,0,0,$a);break;
    case &#39;green&#39;:$cc=imagecolorallocatealpha($i,0,255,0,$a);break;
    case &#39;blue&#39;:$cc=imagecolorallocatealpha($i,0,0,255,$a);break;
    case &#39;orange&#39;:$cc=imagecolorallocatealpha($i,0xff,0x66,0x33,$a);break;
    case &#39;yellow&#39;:$cc=imagecolorallocatealpha($i,255,255,0,$a);break;
    case &#39;rand&#39;:$cc=imagecolorallocatealpha($i,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255),$a);break;
    default:
      $cs = substr($c,1);
      $ok = str_split($cs,2);
      $cc = imagecolorallocatealpha($i,hexdec($ok[0]),hexdec($ok[1]),hexdec($ok[2]),$a);
    break;   
  }
  return $cc;
}
 
 
/**
 * 功能是：返回扩展名
 */
 
function ext($f){
  $exts = explode(&#39;.&#39;,$f);
  return end($exts);
}
 
/**
 * 功能是：返回文件名，不含扩展名
 */
function name($f){
  $s = explode(&#39;/&#39;,$f);
  $fn = end($s);
  return rtrim($fn,&#39;.&#39;.ext($f));
}