php——水印

很多开发语言都会实现水印功能，之前我用OC和swift都实现过，最近学下php，顺便练下手，记录下以便查阅。

<?php //水印function water($source,$water = '1_jaccty.png',$position = 0,$alpha = 100,$type = "jpeg",$path = 'waterTest',$isRandName = true){   //打开图片   $sourceRes = open($source);   $waterRes = open($water);   //获取原图宽高   $source_info = getimagesize($source);   $source_w = $source_info[0];   $source_h = $source_info[1];   //获取水印的宽高   $water_info = getimagesize($water);   $water_w = $water_info[0];   $water_h = $water_info[1];   //计算位置   $image_slipw = $source_w / 3;   $image_sliph = $source_h / 3;   $position_x = ($position % 3-1)*$image_slipw;   $position_y = floor($position / 3)*$image_sliph;   if ($position!=0) {   $x = mt_rand($position_x,$position_x+$image_slipw-$water_w);   $y = mt_rand($position_y,$position_y+$image_sliph-$water_h);   }else{   $x = mt_rand(0,$source_w-$water_w);   $y = mt_rand(0,$source_h-$water_h);   }   //合并   imagecopymerge($sourceRes, $waterRes, $x, $y, 0, 0, $water_w, $water_h, $alpha);   $imageType = 'image'.$type;//根据$type来调用哪个函数   /*   imagepng();   imagejpeg();   imagewbmp();    */      //处理path问题   if ($isRandName) {     $name = uniqid().'.'.$type;   }else{      $pathInfo = pathinfo($source);      $name = $pathInfo['filename'].'.'.$type;   }   $path = rtrim($path,'/').'/'.$name;//防止已有/斜线   $imageType($sourceRes,$path);//画图   imagedestroy($sourceRes);   imagedestroy($waterRes);}//打开图片的函数function open($path){   if (!file_exists($path)) {   exit('文件不存在');   }   $info = getimagesize($path);   switch ($info['mime']) {   case 'image/jpeg':   case 'image/jpg':   case 'image/pjpeg':       $res = imagecreatefromjpeg($path);   break;   case 'image/png':       $res = imagecreatefrompng($path);       break;   case 'image/gif':       $res = imagecreatefromgif($path);       break;   case 'image/wbmp':   case 'image/bmp':       $res = imagecreatefromwbmp($path);       break;   }   return $res;}$source = "1.jpg";water($source); ?>