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.jb51.net'; //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.jb51.net'; //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); } } ?>
总结