例子,php图片水印代码:
 
<?php 
/*
* 功能:php图片水印 (水印支持图片或文字)
* 参数:
* $groundimage   背景图片,即需要加水印的图片,暂只支持gif,jpg,png格式;
* $waterPos 水印位置,有10种状态,0为随机位置;
* 1为顶端居左,2为顶端居中,3为顶端居右;
* 4为中部居左,5为中部居中,6为中部居右;
* 7为底端居左,8为底端居中,9为底端居右;
* $waterImage 图片水印,即作为水印的图片,暂只支持GIF,JPG,PNG格式;
* $waterText 文字水印,即把文字作为为水印,支持ASCII码,不支持中文;
* $textFont 文字大小,值为1、2、3、4或5,默认为5;
* $textColor 文字颜色,值为十六进制颜色值,默认为#FF0000(红色);
*
* 注意:Support GD 2.0,Support FreeType、GIF Read、GIF Create、JPG 、PNG
* $waterImage 和 $waterText 最好不要同时使用,选其中之一即可,优先使用 $waterImage。
* 当$waterImage有效时,参数$waterString、$stringFont、$stringColor均不生效。
* 加水印后的图片的文件名和 $groundImage 一样。
* 作者:longware @ 2004-11-3 14:15:13
*/
function imageWaterMark($groundImage,$waterPos=0,$waterImage=”",$waterText=”",$textFont=5,$textColor=”#FF0000″) 
{ 
  $isWaterImage = FALSE; 
  $formatMsg = “暂不支持该文件格式,请用图片处理软件将图片转换为GIF、JPG、PNG格式。”; 
//读取水印文件 
  if(!emptyempty($waterImage) && file_exists($waterImage)) 
  { 
$isWaterImage = TRUE; 
$water_info = getimagesize($waterImage); 
$water_w   = $water_info[0];//取得水印图片的宽 
$water_h   = $water_info[1];//取得水印图片的高 
switch($water_info[2])//取得水印图片的格式 
{ 
case 1:$water_im = imagecreatefromgif($waterImage);break; 
case 2:$water_im = imagecreatefromjpeg($waterImage);break; 
case 3:$water_im = imagecreatefrompng($waterImage);break; 
default:die($formatMsg); 
} 
  } 
//读取背景图片 
  if(!emptyempty($groundImage) && file_exists($groundImage)) 
  { 
$ground_info = getimagesize($groundImage); 
$ground_w   = $ground_info[0];//取得背景图片的宽 
$ground_h   = $ground_info[1];//取得背景图片的高 
switch($ground_info[2])//取得背景图片的格式 
{ 
case 1:$ground_im = imagecreatefromgif($groundImage);break; 
case 2:$ground_im = imagecreatefromjpeg($groundImage);break; 
case 3:$ground_im = imagecreatefrompng($groundImage);break; 
default:die($formatMsg); 
} 
  } 
  else
  { 
die(”需要加水印的图片不存在!”); 
  } 
//水印位置 
  if($isWaterImage)//图片水印 
  { 
$w = $water_w; 
$h = $water_h; 
$label = “图片的”; 
  } 
  else//文字水印 
  { 
$temp = imagettfbbox(ceil($textFont*5),0,”./cour.ttf”,$waterText);//取得使用 TrueType 字体的文本的范围 
$w = $temp[2] - $temp[6]; 
$h = $temp[3] - $temp[7]; 
unset($temp); 
$label = “文字区域”; 
  } 
  if( ($ground_w<$w) || ($ground_h<$h) ) 
  { 
echo “需要加水印的图片的长度或宽度比水印”.$label.”还小,无法生成水印!”; 
return; 
  } 
  switch($waterPos) 
  { 
case 0://随机 
$posX = rand(0,($ground_w - $w)); 
$posY = rand(0,($ground_h - $h)); 
break; 
case 1://1为顶端居左 
$posX = 0; 
$posY = 0; 
break; 
case 2://2为顶端居中 
$posX = ($ground_w - $w) / 2; 
$posY = 0; 
break; 
case 3://3为顶端居右 
$posX = $ground_w - $w; 
$posY = 0; 
break; 
case 4://4为中部居左 
$posX = 0; 
$posY = ($ground_h - $h) / 2; 
break; 
case 5://5为中部居中 
$posX = ($ground_w - $w) / 2; 
$posY = ($ground_h - $h) / 2; 
break; 
case 6://6为中部居右 
$posX = $ground_w - $w; 
$posY = ($ground_h - $h) / 2; 
break; 
case 7://7为底端居左 
$posX = 0; 
$posY = $ground_h - $h; 
break; 
case 8://8为底端居中 
$posX = ($ground_w - $w) / 2; 
$posY = $ground_h - $h; 
break; 
case 9://9为底端居右 
$posX = $ground_w - $w; 
$posY = $ground_h - $h; 
break; 
default://随机 
$posX = rand(0,($ground_w - $w)); 
$posY = rand(0,($ground_h - $h)); 
break;   
  } 
//设定图像的混色模式 
  imagealphablending($ground_im, true); 
if($isWaterImage)//图片水印 
  { 
imagecopy($ground_im, $water_im, $posX, $posY, 0, 0, $water_w,$water_h);//拷贝水印到目标文件   
  } 
  else//文字水印 
  { 
if( !emptyempty($textColor) && (strlen($textColor)==7) ) 
{ 
$R = hexdec(substr($textColor,1,2)); 
$G = hexdec(substr($textColor,3,2)); 
$B = hexdec(substr($textColor,5)); 
} 
else
{ 
die(”水印文字颜色格式不正确!”); 
} 
imagestring ( $ground_im, $textFont, $posX, $posY, $waterText, imagecolorallocate($ground_im, $R, $G, $B));   
  } 
//生成水印后的图片 
  @unlink($groundImage); 
  switch($ground_info[2])//取得背景图片的格式 
  { 
case 1:imagegif($ground_im,$groundImage);break; 
case 2:imagejpeg($ground_im,$groundImage);break; 
case 3:imagepng($ground_im,$groundImage);break; 
default:die($errorMsg); 
  } 
//释放内存 
  if(isset($water_info)) unset($water_info); 
  if(isset($water_im)) imagedestroy($water_im); 
  unset($ground_info); 
  imagedestroy($ground_im); 
} 
//- www.jb200.com
$id=$_REQUEST['id']; 
$num = count($_FILES['userfile']['name']); 
print_r($_FILES['userfile']); 
print_r($_FILES['userfile']['name']); 
echo $num; 
echo “<bR>”; 
if(isset($id)){ 
 for($i=0;$i<$id;$i++){ 
if(isset($_FILES) && !emptyempty($_FILES['userfile']) && $_FILES['userfile']['size']>0) 
{ 
  $uploadfile = “./”.time().”_”.$_FILES['userfile'][name][$i]; 
  echo “<br>”; 
  echo $uploadfile; 
  if (copy($_FILES['userfile']['tmp_name'][$i], $uploadfile)) 
  { 
echo “OK<br>”; 
//文字水印 
//imageWaterMark($uploadfile,5,”",”HTTP://www.lvye.info”,5,”#cccccc“); 
//图片水印 
$waterImage=”logo_ok1.gif”;//水印图片路径 
imageWaterMark($uploadfile,9,$waterImage); 
echo “<img src=”".$uploadfile.”” border=”0”>”; 
  } 
  else
  { 
echo “Fail<br>”; 
  } 
} 
 } 
} 
?> 
<form enctype=”multipart/form-data” method=”POST”> 
<?php 
for($a=0;$a<$id;$a++){ 
 echo “文件: <input name=”userfile[]” type=”file”><br>”;
} 
?> 
<input type=”submit” value=”上传”> 
</form>