php实现多张图片上传加水印技巧

<?php 
function imageWaterMark($groundImage,$waterPos=0,$waterImage="",$waterText="",$textFont=5,$textColor="#FF0000") 
{ 
$isWaterImage = FALSE; 
$formatMsg = "暂不支持该文件格式，请用图片处理软件将图片转换为GIF、JPG、PNG格式。"; 
//读取水印文件 
if(!empty($waterImage) && file_exists($waterImage)) 
{ 
$isWaterImage = TRUE; 
$water_info = getimagesize($waterImage); //得到的是一个数组 
$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; //将图片转化为PHP可识别的编码过程 
case 2:$water_im = imagecreatefromjpeg($waterImage);break; //将图片转化为PHP可识别的编码过程 
case 3:$water_im = imagecreatefrompng($waterImage);break; //将图片转化为PHP可识别的编码过程 
default:die($formatMsg); 
} 
} 
//读取背景图片 
if(!empty($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*2.5),0,"c:/windows/fonts/stcaiyun.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( !empty($textColor) && (strlen($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,$groundImage);break; //创建gif格式的图片 
case 2:imagejpeg($ground_im,$groundImage);break; //创建jpeg格式的图片 
case 3:imagepng($ground_im,$groundImage);break; //创建png格式的图片 
default:die($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); 
} 
?> 
<?php 
for ($i=0;$i<count($_FILES['userfile']['tmp_name']);$i++) 
{ 
$upfile="./img/".($i+1).".png";//此处路径换成你的 
if(move_uploaded_file($_FILES['userfile']['tmp_name'][$i],$upfile)){ 
imageWaterMark($upfile,9,"./shuiyin.png","Made By Chenduan",5,"#FF0000"); 
/* 
* 功能：图片水印 (水印支持图片或文字) 
* imageWaterMark($groundImage,$waterPos=0,$waterImage="",$waterText="",$textFont=5,$textColor="#FF0000") 
* 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； 
* $textColor 文字颜色，值为十六进制颜色值，默认为#FF0000(红色)； 
*/ 
echo "<img src=\"".$upfile."\" border=\"0\">"; 
echo "第".($i+1)."张图片操作成功<br>"; 
} 
else{ 
echo "第".($i+1)."张图片上传不了<br>"; 
} 
} 
?>