php图片水印和缩略图的功能实现

check($img) || !$this->thumb_on) return FALSE;
        
        //定义缩略图的初始值
        $t_type = $t_type ? $t_type : $this->thumb_type;
        $t_w = $t_w ? $t_w : $this->thumb_width;
        $t_h = $t_h ? $t_h : $this->thumb_height;
        
        //获取到原图的信息
        $img_info = getimagesize($img);
        $img_w = $img_info[0];
        $img_h = $img_info[1];
        //取得图像类型的文件后缀
        $img_type = image_type_to_extension($img_info[2]);
        //获取到相关尺寸
        $thumb_size = $this->thumb_size($img_w,$img_h,$t_w,$t_h,$t_type);
        //确定原始图像类型
        //利用自定义函数来实现图片类型的确定
        $func = "imagecreatefrom".substr($img_type, 1);
        $res_img = $func($img);
        
        //缩略图资源            编辑图片资源moon
        if( $img_type == '.gif' || $img_type == '.png' ){
            $res_thumb = imagecreate($thumb_size[0], $thumb_size[1]);
            $color = imagecolorallocate($res_thumb, 255, 0, 0);
        }else{
            $res_thumb = imagecreatetruecolor($thumb_size[0], $thumb_size[1]);
        }
        
        //制作缩略图
        if(function_exists( "imagecopyresampled" ) ){
            imagecopyresampled($res_thumb, $res_img, 0, 0, 0, 0, $thumb_size[0],$thumb_size[1],$thumb_size[2],$thumb_size[3]);
        }else{
            imagecopyresized($res_thumb, $res_img, 0, 0, 0, 0, $thumb_size[0],$thumb_size[1],$thumb_size[2],$thumb_size[3]);
        }
        //处理透明色
        if( $img_type =='.gif' || $img_type == '.png' ){
            imagecolortransparent($res_thumb,$color);
        }
        
        //配置输出文件名
        $outfile = $outfile ? $outfile : $outfile.substr($img,0,strripos($img,'.')).$this->thumb_fix.$img_type;
        
        //文件的保存输出
        $func = "image".substr($img_type, 1);
        $func($res_thumb,$outfile);
        if(isset($res_thumb)) imagedestroy ($res_thumb);
        if(isset($res_img)) imagedestroy ($res_img);
        return $outfile;
    } 

    public function watermark( $img,$pos='',$out_img='',$water_img='',$text='' ){
        if(!$this->check($img) || !$this->watermark_on) return false;
        
        $water_img = $water_img ? $water_img : $this->water_img;
        //水印的开启状态
        $waterimg_on = $this->check($water_img) ? 1 : 0;
        //判断是否在原图上操作
        $out_img = $out_img ? $out_img : $img;
        //判断水印的位置
        $pos = $pos ? $pos : $this->pos;
        //水印文字
        $text = $text ? $text : $this->text;
        
        
        $img_info = getimagesize($img);
        $img_w = $img_info[0];
        $img_h = $img_info[1];
        //判断水印图片的类型
        
        
        if( $waterimg_on ){
            $w_info = getimagesize($water_img);
            $w_w = $w_info[0];
            $w_h = $w_info[1];
            if ( $img_w < $w_w || $img_h < $w_h ) return false;
            switch ( $w_info[2] ){
                case 1:
                    $w_img = imagecreatefromgif($water_img);
                    break;
                case 2:
                    $w_img = imagecreatefromjpeg($water_img);
                    break;
                case 3:
                    $w_img = imagecreatefrompng($water_img);
                    break;
            }
        }else{
            if( empty($text) || strlen($this->color)!=7 ) return FALSE;
            $text_info = imagettfbbox($this->size, 0, $this->font, $text);
            $w_w = $text_info[2] - $text_info[6];
            $w_h = $text_info[3] - $text_info[7];
        }
        
        //建立原图资源
        
        switch ( $img_info[2] ){
            case 1:
                $res_img = imagecreatefromgif($img);
                break;
            case 2:
                $res_img = imagecreatefromjpeg($img);
                break;
            case 3:
                $res_img = imagecreatefrompng($img);
                break;
        }
        //确定水印的位置
        switch ( $pos ){
            case 1:
                $x = $y =25;
                break;
            case 2:
                $x = ($img_w - $w_w)/2; 
                $y = 25;
                break;
            case 3:
                $x = $img_w - $w_w;
                $y = 25;
                break;
            case 4:
                $x = 25;
                $y = ($img_h - $w_h)/2;
                break;
            case 5:
                $x = ($img_w - $w_w)/2; 
                $y = ($img_h - $w_h)/2;
                break;
            case 6:
                $x = $img_w - $w_w;
                $y = ($img_h - $w_h)/2;
                break;
            case 7:
                $x = 25;
                $y = $img_h - $w_h;
                break;
            case 8:
                $x = ($img_w - $w_w)/2;
                $y = $img_h - $w_h;
                break;
            case 9:
                $x = $img_w - $w_w;
                $y = $img_h - $w_h;
                break;
            default :
                $x = mt_rand(25, $img_w - $w_w);
                $y = mt_rand(25, $img_h - $w_h);
        }
        
        //写入图片资源
        if( $waterimg_on ){
            imagecopymerge($res_img, $w_img, $x, $y, 0, 0, $w_w, $w_h, $this->pct);  
    }else{
        $r = hexdec(substr($this->color, 1,2));
        $g = hexdec(substr($this->color, 3,2));
        $b = hexdec(substr($this->color, 5,2));
        $color = imagecolorallocate($res_img, $r, $g, $b);
        imagettftext($res_img, $this->size, 0, $x, $y, $color, $this->font, $text);    
    }
    
    //生成图片类型
    switch ( $img_info[2] ){
        case 1:
            imagecreatefromgif($res_img,$out_img);
            break;
        case 2:
            //imagecreatefromjpeg($res_img,$out_img);
            imagejpeg($res_img,$out_img);
            break;
        case 3:
            imagepng($res_img,$out_img);
            break;
    }
    if(isset($res_img)) imagedestroy ($res_img);
    if(isset($w_img))   imagedestroy($w_img);
    return TRUE;
}   
    //验证图片是否存在
        private function check($img){
            $type = array('.jpg','.jpeg','.png','.gif');
            $img_type = strtolower(strrchr($img, '.'));
            return extension_loaded('gd') && file_exists($img) && in_array($img_type, $type);
        } 
        
        //获取缩略图的相关比例
        //获取到图片的处理类型
        private function thumb_size( $img_w,$img_h,$t_w,$t_h,$t_type){
            //定义缩略图尺寸
            $w = $t_w;
            $h = $t_h;
            
            //定义图片的原始尺寸
            $cut_w = $img_w;
            $cut_h = $img_h;
            
            //当要目标图像小于缩略图的尺寸时；
            if( $img_w <= $t_w && $img_h < $t_h ){
                $w = $img_w;
                $h = $img_h;
            }else{
                if( !empty($t_type) && $t_type>0 ){
                    switch ( $t_type ){
                        //当宽度固定时
                        case 1:
                            $h = $t_w/$img_w*$img_h;
                            break;
                        //高度固定时
                        case 2:
                            $w = $t_h/$img_h*$img_w;
                            break;
                        //宽度固定，高度裁切
                        case 3:
                            $cut_h = $img_w/$t_w*$t_h;
                            break;
                        //高度固定，宽度裁切
                        case 4:
                            $cut_w = $img_h/$t_h*$t_w;
                            break;
                        //等比例缩放
                        default :
                            if( ($img_w/$t_w) > ($img_h/$t_h) ){
                              $h = $t_w/$img_w*$t_h;
                            }elseif( ($img_w/$t_w) < ($img_h/$t_h) ){
                                $w = $t_h/$img_h*$t_w;
                            }else{
                                $w = $t_w;
                                $h = $t_h;
                            }
                    }
                }
                
                
            }
            $arr[0] = $t_w;
            $arr[1] = $t_h;
            $arr[2] = $cut_w;
            $arr[3] = $cut_h;
            return $arr;
    }
}