使用GD库做图片水印

    1. png图片作为水印加到其他类型图片后,背景变黑色 
      原因: imagecopy函数拷贝时可以保留png图像的原透明信息,而imagecopymerge却不支持图片的本身的透明拷贝。 
      然后直接上代码:
      /*
          * 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.
       
          */
          public static function FoximageWaterMark($groundImage,$waterPos=0,$waterImage="",$waterText="",$textFont=5,$textColor="#595959")
          {
              $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])//取得背景图片的格式
                  {
                      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*5.5),0,"0",$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($isWaterImage)//图片水印
              {
                  // imagecopy函数拷贝时可以保留png图像的原透明信息,而imagecopymerge却不支持图片的本身的透明拷贝
                  imagecopy($ground_im, $water_im, $posX, $posY, 0, 0, $water_w, $water_h);
      //            imagecopymerge($ground_im, $water_im, $posX, $posY, 0, 0, $water_w,$water_h,20);//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!");
                  }
       
               // imagettftext ($ground_im, 20,0, 20, 30, imagecolorallocate($ground_im, $R, $G, $B),base_url()."/water.ttf","麦言社区");
                  imagestring ( $ground_im, $textFont, $posX, $posY, $waterText, imagecolorallocatealpha($ground_im, $R, $G, $B,100));
              }
              //生成水印后的图片
              @unlink($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);
          }
      

        

        

posted @ 2017-05-25 15:47  佚小名  阅读(494)  评论(0编辑  收藏  举报