php图片添加文字水印实现代码

php类库给现有的图片加文字水印，代码不是很完善，欢迎大家多多指教！代码如下：

    <?php
    /*PHP图片加文字水印类库
    QQ:3697578482 伤心的歌
    该类库暂时只支持文字水印，位置为右下角，颜色随机
    调用方法：
    1、在需要加水印的文件顶部引入类库：
    include_once 'imageClass.php';
    2、声明新类：
    $tpl=new image_fu;
    3、给图片水印提供参数：
    $tpl->img(图片路径,水印文字,字体路径,字体大小,字体角度);
    比如：$tpl->img('abc.jpg','这是水印文字','ziti.ttf',30,0)
    */
    class image_fu{
    private $image;
    private $img_info;
    private $img_width;
    private $img_height;
    private $img_im;
    private $img_text;
    private $img_ttf='';
    private $img_new;
    private $img_text_size;
    private $img_jd;
    function img($img='',$txt='',$ttf='',$size=12,$jiaodu=0){
    if(isset($img)&&file;_exists($img)){//检测图片是否存在
    $this->image =$img;
    $this->img_text=$txt;
    $this->img_text_size=$size;
    $this->img_jd=$jiaodu;
    if(file_exists($ttf)){
    $this->img_ttf=$ttf;
    }else{
    exit('字体文件：'.$ttf.'不存在！');
    }
    $this->imgyesno();
    }else{
    exit('图片文件:'.$img.'不存在');
    }
    }
    private function imgyesno(){
    $this->img_info =getimagesize($this->image);
    $this->img_width =$this->img_info[0];//图片宽
    $this->img_height=$this->img_info[1];//图片高
    //检测图片类型
    switch($this->img_info[2]){
    case 1:$this->img_im = imagecreatefromgif($this->image);break;
    case 2:$this->img_im = imagecreatefromjpeg($this->image);break;
    case 3:$this->img_im = imagecreatefrompng($this->image);break;
    default:exit('图片格式不支持水印');
    }
    $this->img_text();
    }
    private function img_text(){
    imagealphablending($this->img_im,true);
    //设定颜色
    $color=imagecolorallocate($this->img_im,rand(0,255),rand(0,255),rand(0,255));
    $txt_height=$this->img_text_size;
    $txt_jiaodu=$this->img_jd;
    $ttf_im=imagettfbbox($txt_height,$txt_jiaodu,$this->img_ttf,$this->img_text);
    $w = $ttf_im[2] - $ttf_im[6];
    $h = $ttf_im[3] - $ttf_im[7];
    //$w = $ttf_im[7];
    //$h = $ttf_im[8];
    unset($ttf_im);
    $txt_y =$this->img_height-$h;
    $txt_x =$this->img_width-$w;
    //$txt_y =0;
    //$txt_x =0;
    $this->img_new=@imagettftext($this->img_im,$txt_height,$txt_jiaodu,$txt_x,$txt_y,$color,$this->img_ttf,$this->img_text);
    @unlink($this->image);//删除图片
    switch($this->img_info[2]) {//取得背景图片的格式
    case 1:imagegif($this->img_im,$this->image);break;
    case 2:imagejpeg($this->img_im,$this->image);break;
    case 3:imagepng($this->img_im,$this->image);break;
    default: exit('水印图片失败');
    }
    }
    //显示图片
    function img_show(){echo '<img src="'.$this->image.'" border="0" alt="'.$this->img_text.'" />';}
    //释放内存
    private function img_nothing(){
    unset($this->img_info);
    imagedestroy($this->img_im);
    }
    }
    ?>

以上就是本文的全部内容，希望对大家的学习有所帮助。