超酷PHP图片水印

<?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(!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($groundImage) && file_exists($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,"./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( !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;
        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);
}


//---------------------------------------------------------------------------------------

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://BLOG.CSDN.NET/LONGWARE/",5,"#FF0000");

        //图片水印
        //$waterImage="./Hanweb_shuiyin.gif";//水印图片路径
        //imageWaterMark($uploadfile,0,$waterImage);

        echo "<img src=\"".$uploadfile."\" border=\"0\">";
    }
    else
    {
        echo "Fail<br>";
    }
}
?>
<form enctype="multipart/form-data" method="POST">
文件: <input name="userfile" type="file">
<input type="submit" value="上传">
</form>

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因工作需要，写了个图片水印函数。
因中文字体较大，中文处理暂未加入，cour.ttf在%windir%\fonts\下。
图片水印处理方法很多，在此抛砖引玉了。