PHP實現的給圖片添加水印功能，可添加文字水印或圖片水印，使用文字水印時需要提供字體文件，使用圖片水印時需要提供水印圖片，水印圖片不能比要添加水印的圖片大，請使用背景透明的水印圖片。
?php
/**
* 圖片加水印類，支持文字水印、透明度設置、自定義水印位置等。
* 使用示例：
* $obj = new WaterMask($imgFileName); //實例化對象
* $obj->$waterType = 1; //類型：0為文字水印、1為圖片水印
* $obj->$transparent = 45; //水印透明度
* $obj->$waterStr = 'www.jb51.net'; //水印文字
* $obj->$fontSize = 18; //文字字體大小
* $obj->$fontColor = array(255,255,255); //水印文字顏色（RGB）
* $obj->$fontFile = 'AHGBold.ttf'; //字體文件
* ……
* $obj->output(); //輸出水印圖片文件覆蓋到輸入的圖片文件
*/
class WaterMask{
public $waterType = 0; //水印類型：0為文字水印、1為圖片水印
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; //文字字體大小
public $fontColor = array(255,255,255); //水印文字顏色（RGB）
public $fontFile = 'AHGBold.ttf'; //字體文件
public $waterImg = 'logo.png'; //水印圖片
private $srcImg = ''; //需要添加水印的圖片
private $im = ''; //圖片句柄
private $water_im = ''; //水印圖片句柄
private $srcImg_info = ''; //圖片信息
private $waterImg_info = ''; //水印圖片信息
private $str_w = ''; //水印文字寬度
private $str_h = ''; //水印文字高度
private $x = ''; //水印X坐標
private $y = ''; //水印y坐標
function __construct($img) { //析構函數
$this->srcImg = file_exists($img) ? $img : die('"'.$img.'" 源文件不存在！');
}
private function imginfo() { //獲取需要添加水印的圖片的信息，并載入圖片。
$this->srcImg_info = getimagesize($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('原圖片（'.$this->srcImg.'）格式不對，只支持PNG、JPEG、GIF。');
}
}
private function waterimginfo() { //獲取水印圖片的信息，并載入圖片。
$this->waterImg_info = getimagesize($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('水印圖片（'.$this->srcImg.'）格式不對，只支持PNG、JPEG、GIF。');
}
}
private function waterpos() { //水印位置算法
switch ($this->pos) {
case 0: //隨機位置
$this->x = rand(0,$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('水印比原圖大！');
}
$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('添加水印失敗！');
break;
}
imagedestroy($this->im);
imagedestroy($this->water_im);
}
}
?>
