PHP添加文字水印或图片水印的水印类完整源代码与使用示例

江南才子

PHP实现的给图片添加水印功能，可添加文字水印或图片水印，使用文字水印时需要提供字体文件，使用图片水印时需要提供水印图片，水印图片不能比要添加水印的图片大，请使用背景透明的水印图片。
该水印类支持自定义水印位置、自定义水印大小和水印的透明度，字体水印可自定义颜色等，功能已相应完善。
完整源代码如下(注解中已给出使用示例)：

<?php
/**
 * 图片加水印类，支持文字水印、透明度设置、自定义水印位置等。
 * 使用示例：
 *   $obj = new WaterMask($imgFileName);  //实例化对象
 *   $obj->$waterType = 1;   //类型：0为文字水印、1为图片水印
 *   $obj->$transparent = 45;   //水印透明度
 *   $obj->$waterStr = 'www.zzvips.com';  //水印文字
 *   $obj->$fontSize = 18;   //文字字体大小
 *   $obj->$fontColor = array(255,255,255);  //水印文字颜色（RGB）
 *   $obj->$fontFile = 'AHGBold.ttf';  //字体文件
 * ……
 *   $obj->output();  //输出水印图片文件覆盖到输入的图片文件
 */
class WaterMask{
  public $waterType   = 0;   //水印类型：0为文字水印、1为图片水印
  public $pos    = 0;   //水印位置
  public $transparent  = 45;   //水印透明度
  public $waterStr    = 'www.zzvips.com';  //水印文字
  public $fontSize    = 18;   //文字字体大小
  public $fontColor   = array(255,255,255);  //水印文字颜色（RGB）
  public $fontFile    = 'AHGBold.ttf';  //字体文件
  public $waterImg    = 'logo.png';  //水印图片
  private $srcImg     = '';   //需要添加水印的图片
  private $im     = '';   //图片句柄
  private $water_im    = '';   //水印图片句柄
  private $srcImg_info  = '';   //图片信息
  private $waterImg_info   = '';   //水印图片信息
  private $str_w     = '';   //水印文字宽度
  private $str_h     = '';   //水印文字高度
  private $x     = '';   //水印X坐标
  private $y     = '';   //水印y坐标
  function __construct($img) {  //析构函数
  $this->srcImg = file_exists($img) ? $img : die('"'.$img.'" 源文件不存在！');
  }
  private function imginfo() { //获取需要添加水印的图片的信息，并载入图片。
  $this->srcImg_info = getimagesize($this->srcImg);
  switch ($this->srcImg_info[2]) {
    case 3:
    $this->im = imagecreatefrompng($this->srcImg);
    break 1;
    case 2:
    $this->im = imagecreatefromjpeg($this->srcImg);
    break 1;
    case 1:
    $this->im = imagecreatefromgif($this->srcImg);
    break 1;
    default:
    die('原图片（'.$this->srcImg.'）格式不对，只支持PNG、JPEG、GIF。');
  }
  }
  private function waterimginfo() { //获取水印图片的信息，并载入图片。
  $this->waterImg_info = getimagesize($this->waterImg);
  switch ($this->waterImg_info[2]) {
    case 3:
    $this->water_im = imagecreatefrompng($this->waterImg);
    break 1;
    case 2:
    $this->water_im = imagecreatefromjpeg($this->waterImg);
    break 1;
    case 1:
    $this->water_im = imagecreatefromgif($this->waterImg);
    break 1;
    default:
    die('水印图片（'.$this->srcImg.'）格式不对，只支持PNG、JPEG、GIF。');
  }
  }
  private function waterpos() { //水印位置算法
  switch ($this->pos) {
    case 0:   //随机位置
    $this->x = rand(0,$this->srcImg_info[0]-$this->waterImg_info[0]);
    $this->y = rand(0,$this->srcImg_info[1]-$this->waterImg_info[1]);
    break 1;
    case 1:   //上左
    $this->x = 0;
    $this->y = 0;
    break 1;
    case 2:   //上中
    $this->x = ($this->srcImg_info[0]-$this->waterImg_info[0])/2;
    $this->y = 0;
    break 1;
    case 3:   //上右
    $this->x = $this->srcImg_info[0]-$this->waterImg_info[0];
    $this->y = 0;
    break 1;
    case 4:   //中左
    $this->x = 0;
    $this->y = ($this->srcImg_info[1]-$this->waterImg_info[1])/2;
    break 1;
    case 5:   //中中
    $this->x = ($this->srcImg_info[0]-$this->waterImg_info[0])/2;
    $this->y = ($this->srcImg_info[1]-$this->waterImg_info[1])/2;
    break 1;
    case 6:   //中右
    $this->x = $this->srcImg_info[0]-$this->waterImg_info[0];
    $this->y = ($this->srcImg_info[1]-$this->waterImg_info[1])/2;
    break 1;
    case 7:   //下左
    $this->x = 0;
    $this->y = $this->srcImg_info[1]-$this->waterImg_info[1];
    break 1;
    case 8:   //下中
    $this->x = ($this->srcImg_info[0]-$this->waterImg_info[0])/2;
    $this->y = $this->srcImg_info[1]-$this->waterImg_info[1];
    break 1;
    default:  //下右
    $this->x = $this->srcImg_info[0]-$this->waterImg_info[0];
    $this->y = $this->srcImg_info[1]-$this->waterImg_info[1];
    break 1;
  }
  }
  private function waterimg() {
  if ($this->srcImg_info[0] <= $this->waterImg_info[0] || $this->srcImg_info[1] <= $this->waterImg_info[1]){
    die('水印比原图大！');
  }
  $this->waterpos();
  $cut = imagecreatetruecolor($this->waterImg_info[0],$this->waterImg_info[1]);
  imagecopy($cut,$this->im,0,0,$this->x,$this->y,$this->waterImg_info[0],$this->waterImg_info[1]);
  $pct = $this->transparent;
  imagecopy($cut,$this->water_im,0,0,0,0,$this->waterImg_info[0],$this->waterImg_info[1]);
  imagecopymerge($this->im,$cut,$this->x,$this->y,0,0,$this->waterImg_info[0],$this->waterImg_info[1],$pct);
  }
  private function waterstr() {
  $rect = imagettfbbox($this->fontSize,0,$this->fontFile,$this->waterStr);
  $w = abs($rect[2]-$rect[6]);
  $h = abs($rect[3]-$rect[7]);
  $fontHeight = $this->fontSize;
  $this->water_im = imagecreatetruecolor($w, $h);
  imagealphablending($this->water_im,false);
  imagesavealpha($this->water_im,true);
  $white_alpha = imagecolorallocatealpha($this->water_im,255,255,255,127);
  imagefill($this->water_im,0,0,$white_alpha);
  $color = imagecolorallocate($this->water_im,$this->fontColor[0],$this->fontColor[1],$this->fontColor[2]);
  imagettftext($this->water_im,$this->fontSize,0,0,$this->fontSize,$color,$this->fontFile,$this->waterStr);
  $this->waterImg_info = array(0=>$w,1=>$h);
  $this->waterimg();
  }
  function output() {
  $this->imginfo();
  if ($this->waterType == 0) {
    $this->waterstr();
  }else {
    $this->waterimginfo();
    $this->waterimg();
  }
  switch ($this->srcImg_info[2]) {
    case 3:
    imagepng($this->im,$this->srcImg);
    break 1;
    case 2:
    imagejpeg($this->im,$this->srcImg);
    break 1;
    case 1:
    imagegif($this->im,$this->srcImg);
    break 1;
    default:
    die('添加水印失败！');
    break;
  }
  imagedestroy($this->im);
  imagedestroy($this->water_im);
  }
}
?>

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