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

    <?php
    header('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);
        } 
    }

2. test1.php

    <?php

    /* 
     * 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.
     */
    //header('Content-Type:text/html;charset=utf-8');
    include 'water.class.php';
    $image = new Water();
    $image->watermark('12.jpg',5);
    //$image->watermark('12.jpg',1);

3.效果图

以上就是本文的全部内容，希望对大家学习PHP程序设计有所帮助。