PHP imagecopy()与imagecopymerge()图像添加水印

header("Content-type: image/jpeg");

//原始图像
$dst = "images/flower_1.jpg";

//得到原始图片信息
$dst_im = imagecreatefromjpeg($dst);
$dst_info = getimagesize($dst);

//水印图像
$src = "images/logo.gif";
$src_im = imagecreatefromgif($src);
$src_info = getimagesize($src);

//水印透明度
$alpha = 30;

//合并水印图片
imagecopymerge($dst_im,$src_im,$dst_info[0]-$src_info[0],$dst_info[1]-$src_info[1],0,0,$src_info[0],
$src_info[1],$alpha);

//输出合并后水印图片
imagejpeg($dst_im);
imagedestroy($dst_im);
imagedestroy($src_im);
?>

新版本之后imagecopymerge函数几乎不使用了，我们可直接使用imagecopy来生成水印两个函数的功能是完全一样的。

//增加水印
$watermark   =1;
$watertype   =2;
$waterstring =''; 
$waterimg="z.png";    //水印图片
$sFilePath ='aa.jpg';
if($watermark==1)
{
 $image_size = getimagesize($sFilePath); //上传的图片
 $water_size = getimagesize($waterimg);  //水印图片
 $iinfo=getimagesize($sFilePath,$iinfo);
 $nimage=imagecreatetruecolor($image_size[0],$image_size[1]);
 $white=imagecolorallocate($nimage,255,255,255);
 $black=imagecolorallocate($nimage,0,0,0);
 $red=imagecolorallocate($nimage,255,0,0);
 imagefill($nimage,0,0,$white);
 switch ($iinfo[2])
 {
  case 1:
   $simage =imagecreatefromgif($sFilePath);
   break;
  case 2:
   $simage =imagecreatefromjpeg($sFilePath);
   break;
  case 3:
   $simage =imagecreatefrompng($sFilePath);
   break;
//            case 6:
//            $simage =imagecreatefromwbmp($sFilePath);
//            break;
  default:
   die("不支持的文件类型");
   exit;
 }
 
 imagecopy($nimage,$simage,0,0,0,0,$image_size[0],$image_size[1]);
 
 switch($watertype)
 {
  case 1:   //加水印字符串
   imagestring($nimage,2,3,$image_size[1]-15,$waterstring,$black);
   break;
  case 2:   //加水印图片
   $simage1 =imagecreatefrompng($waterimg);     
   $x= $image_size[0]-$water_size[0];
   $y= $image_size[1]-$water_size[1];
   imagecopy($nimage,$simage1,$x,$y,0,0,240,65);
   imagedestroy($simage1);
   break;
 }
    
 switch ($iinfo[2])
 {
  case 1:
   imagegif($nimage, $sFilePath);
//            imagejpeg($nimage, $sFilePath);
   break;
  case 2:
   imagejpeg($nimage, $sFilePath);
   break;
  case 3:
   imagepng($nimage, $sFilePath);
   break;
//            case 6:
//            imagewbmp($nimage, $sFilePath);
//            //imagejpeg($nimage, $sFilePath);
//            break;
 }
 
 //覆盖原上传文件
 imagedestroy($nimage);
 imagedestroy($simage);
}

class ImageTool { 
    // imageInfo 分析图片的信息 
    // return array() 
    public static function imageInfo($image) { 
        // 判断图片是否存在 
        if (!file_exists($image)) { 
            return false; 
        } 
 
        $info = getimagesize($image); 
 
        if ($info == false) { 
            return false; 
        } 
 
        // 此时info分析出来,是一个数组 
        $img['width'] = $info[0]; 
        $img['height'] = $info[1]; 
        $img['ext'] = substr($info['mime'], strpos($info['mime'], '/') + 1); 
 
        return $img; 
    } 
 
    /*
     加水印功能
     parm String $dst 等操作图片
     parm String $water 水印小图
     parm String $save,不填则默认替换原始图
     */ 
    public static function water($dst, $water, $save = NULL, $pos = 2, $alpha = 50) { 
        // 先保证2个图片存在 
        if (!file_exists($dst) || !file_exists($water)) { 
            return false; 
        } 
 
        // 首先保证水印不能比待操作图片还大 
        $dinfo = self::imageInfo($dst); 
        $winfo = self::imageInfo($water); 
 
        if ($winfo['height'] > $dinfo['height'] || $winfo['width'] > $dinfo['width']) { 
            return false; 
        } 
 
        // 两张图,读到画布上! 但是图片可能是png,可能是jpeg,用什么函数读? 
        $dfunc = 'imagecreatefrom' . $dinfo['ext']; 
        $wfunc = 'imagecreatefrom' . $winfo['ext']; 
 
        if (!function_exists($dfunc) || !function_exists($wfunc)) { 
            return false; 
        } 
 
        // 动态加载函数来创建画布 
        $dim = $dfunc($dst); 
        // 创建待操作的画布 
        $wim = $wfunc($water); 
        // 创建水印画布 
 
        // 根据水印的位置 计算粘贴的坐标 
        switch($pos) { 
            case 0 : 
                // 左上角 
                $posx = 0; 
                $posy = 0; 
                break; 
 
            case 1 : 
                // 右上角 
                $posx = $dinfo['width'] - $winfo['width']; 
                $posy = 0; 
                break; 
 
            case 3 : 
                // 左下角 
                $posx = 0; 
                $posy = $dinfo['height'] - $winfo['height']; 
                break; 
 
            default : 
                $posx = $dinfo['width'] - $winfo['width']; 
                $posy = $dinfo['height'] - $winfo['height']; 
        } 
 
        // 加水印 
        imagecopymerge($dim, $wim, $posx, $posy, 0, 0, $winfo['width'], $winfo['height'], $alpha); 
 
        // 保存 
        if (!$save) { 
            $save = $dst; 
            unlink($dst); 
            // 删除原图 
        } 
 
        $createfunc = 'image' . $dinfo['ext']; 
        $createfunc($dim, $save); 
 
        imagedestroy($dim); 
        imagedestroy($wim); 
 
        return true; 
    } 
 
    /**
     thumb 生成缩略图
     等比例缩放,两边留白
     **/ 
    public static function thumb($dst, $save = NULL, $width = 200, $height = 200) { 
        // 首先判断待处理的图片存不存在 
        $dinfo = self::imageInfo($dst); 
        if ($dinfo == false) { 
            return false; 
        } 
 
        // 计算缩放比例 
        $calc = min($width / $dinfo['width'], $height / $dinfo['height']); 
 
        // 创建原始图的画布 
        $dfunc = 'imagecreatefrom' . $dinfo['ext']; 
        $dim = $dfunc($dst); 
 
        // 创建缩略画布 
        $tim = imagecreatetruecolor($width, $height); 
 
        // 创建白色填充缩略画布 
        $white = imagecolorallocate($tim, 255, 255, 255); 
 
        // 填充缩略画布 
        imagefill($tim, 0, 0, $white); 
 
        // 复制并缩略 
        $dwidth = (int)$dinfo['width'] * $calc; 
        $dheight = (int)$dinfo['height'] * $calc; 
 
        $paddingx = (int)($width - $dwidth) / 2; 
        $paddingy = (int)($height - $dheight) / 2; 
 
        imagecopyresampled($tim, $dim, $paddingx, $paddingy, 0, 0, $dwidth, $dheight, $dinfo['width'],

$dinfo['height']); 
 
        // 保存图片 
        if (!$save) { 
            $save = $dst; 
            unlink($dst); 
        } 
 
        $createfunc = 'image' . $dinfo['ext']; 
        $createfunc($tim, $save); 
 
        imagedestroy($dim); 
        imagedestroy($tim); 
 
        return true; 
 
    } 
 
}