php实现图片上传时添加文字和图片水印技巧

本文实现的功能特别适用于一些商城和图片站中，分享了图片在上传时添加文字和图片水印的技巧，供大家参考，具体内容如下

1. water.class.php

<?phpheader('Content-Type:text/html;charset=utf-8');/*  * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. *///给图片添加水印Class Water{  //开启水印  private $watermark_on = '1';     public $water_img;     //水印位置  public $pos = 1;       //压缩比  public $pct = 80;     //透明度  public $quality = 80;     public $text = '乐趣网zlblog.sinaapp.com';     public $size = 12;     public $color = '#000000';     public $font = 'font.ttf';     public function watermark( $img,$pos='',$out_img='',$water_img='',$text='' ){    if(!$this->check($img) || !$this->watermark_on) return false;         $water_img = $water_img ? $water_img : $this->water_img;    //水印的开启状态    $waterimg_on = $this->check($water_img) ? 1 : 0;    //判断是否在原图上操作    $out_img = $out_img ? $out_img : $img;    //判断水印的位置    $pos = $pos ? $pos : $this->pos;    //水印文字    $text = $text ? $text : $this->text;              $img_info = getimagesize($img);    $img_w = $img_info[0];    $img_h = $img_info[1];    //判断水印图片的类型              if( $waterimg_on ){      $w_info = getimagesize($water_img);      $w_w = $w_info[0];      $w_h = $w_info[1];      if ( $img_w < $w_w || $img_h < $w_h ) return false;      switch ( $w_info[2] ){        case 1:          $w_img = imagecreatefromgif($water_img);          break;        case 2:          $w_img = imagecreatefromjpeg($water_img);          break;        case 3:          $w_img = imagecreatefrompng($water_img);          break;      }    }else{      if( empty($text) || strlen($this->color)!=7 ) return FALSE;      $text_info = imagettfbbox($this->size, 0, $this->font, $text);      $w_w = $text_info[2] - $text_info[6];      $w_h = $text_info[3] - $text_info[7];    }         //建立原图资源         switch ( $img_info[2] ){      case 1:        $res_img = imagecreatefromgif($img);        break;      case 2:        $res_img = imagecreatefromjpeg($img);        break;      case 3:        $res_img = imagecreatefrompng($img);        break;    }    //确定水印的位置    switch ( $pos ){      case 1:        $x = $y =25;        break;      case 2:        $x = ($img_w - $w_w)/2;         $y = 25;        break;      case 3:        $x = $img_w - $w_w;        $y = 25;        break;      case 4:        $x = 25;        $y = ($img_h - $w_h)/2;        break;      case 5:        $x = ($img_w - $w_w)/2;         $y = ($img_h - $w_h)/2;        break;      case 6:        $x = $img_w - $w_w;        $y = ($img_h - $w_h)/2;        break;      case 7:        $x = 25;        $y = $img_h - $w_h;        break;      case 8:        $x = ($img_w - $w_w)/2;        $y = $img_h - $w_h;        break;      case 9:        $x = $img_w - $w_w;        $y = $img_h - $w_h;        break;      default :        $x = mt_rand(25, $img_w - $w_w);        $y = mt_rand(25, $img_h - $w_h);    }         //写入图片资源    if( $waterimg_on ){      imagecopymerge($res_img, $w_img, $x, $y, 0, 0, $w_w, $w_h, $this->pct);   }else{    $r = hexdec(substr($this->color, 1,2));    $g = hexdec(substr($this->color, 3,2));    $b = hexdec(substr($this->color, 5,2));    $color = imagecolorallocate($res_img, $r, $g, $b);    imagettftext($res_img, $this->size, 0, $x, $y, $color, $this->font, $text);    }     //生成图片类型  switch ( $img_info[2] ){    case 1:      imagecreatefromgif($res_img,$out_img);      break;    case 2:      //imagecreatefromjpeg($res_img,$out_img);      imagejpeg($res_img,$out_img);      break;    case 3:      imagejpeg($res_img,$out_img);      break;  }  if(isset($res_img)) imagedestroy ($res_img);  if(isset($w_img))  imagedestroy($w_img);  return TRUE;}    //验证图片是否存在    private function check($img){      $type = array('.jpg','.jpeg','.png','.gif');      $img_type = strtolower(strrchr($img, '.'));      return extension_loaded('gd') && file_exists($img) && in_array($img_type, $type);    } }