PHP实例代码：图片加水印

//水印代码：
/* 
* 功能：PHP图片水印 (水印支持图片或文字) 
* 参数： 
*      $product_img    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 $product_img 一样。 
*/
 
//$product_img="data/upload/566fbbad2e83f.png";
//$waterImage="data/upload/waterimg/san7.png";
//imageWaterMark($product_img,0,$waterImage,'',9,'');
function imageWaterMark($product_img,$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。"; 
    
    //echo $waterImage;  
    //print_r(file_exists("data/upload/waterimg/san.png"));die();  
    //读取水印文件    
    if(!empty($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(!empty($product_img) && file_exists($product_img)) 
    { 
      $ground_info = getimagesize($product_img); 
      $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:
            $ground_im = imagecreatefromgif($product_img);
            break; 
                        
            case 2:
            $ground_im = imagecreatefromjpeg($product_img);
            break; 
                        
            case 3:
            $ground_im = imagecreatefrompng($product_img);
            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,"arial.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; 
    } 
    
    $waterPos=9;    
    switch($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($product_img); 
        
    switch($ground_info[2])
    { //取得背景图片的格式       
        case 1:
        imagegif($ground_im,$product_img);
        break; 
                
        case 2:
        imagejpeg($ground_im,$product_img);
        break; 
                
        case 3:
        imagepng($ground_im,$product_img);
        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); 
}
//--------------------------------------------------------------------------------------- 
if(isset($_FILES) && !empty($_FILES['userfile']) && $_FILES['userfile']['size']>0) 
{   
    $uploadfile = "./".time()."_".$_FILES['userfile']['name'];  
    if(copy($_FILES['userfile']['tmp_name'],$uploadfile)) 
    {         
        echo"OK<br>"; 
                
        //文字水印 
        imageWaterMark($uploadfile,0,"","http://www.seoalphas.com",5,"#FF0000"); 
                
        //图片水印      
        //$waterImage="images/bz.gif";//水印图片路径        
        //imageWaterMark($uploadfile,0,$waterImage);        
        echo "<img src='".$uploadfile."' border='0'>"; 
    }else{        
        echo "Fail<br>"; 
    } 
}