php实现的支持imagemagick及gd库两种处理的缩略图生成类

private $_log = null; // log file
private $_handler = null; // 进行图片处理的程序,imagemagick/gd库
private $_type = 'fit'; // fit or crop
private $_source = null; // 原图路径
private $_dest = null; // 缩略图路径
private $_watermark = null; // 水印图片
private $_opacity = 75; // 水印圖片透明度,gd库不支持
private $_gravity = 'SouthEast'; // 水印摆放位置 NorthWest,North,NorthEast,West,Center,East,SouthWest,South,SouthEast
private $_geometry = '+10+10'; // 水印定位,gd库不支持
private $_croppos = 'TL'; // 截图的位置 TL TM TR ML MM MR BL BM BR
private $_bgcolor = null; // 填充的背景色
private $_quality = 90; // 生成的图片质量
private $_width = null; // 指定区域宽度
private $_height = null; // 指定区域高度

// 初始化
public function __construct($logfile=''){
if($logfile!=''){
$this->_log = $logfile;
}
}

// 设置参数
public function set_config($param=array()){
$this->_handler = $this->exists($param,'handler')? strtolower($param['handler']) : null;
$this->_type = $this->exists($param,'type')? strtolower($param['type']) : 'fit';
$this->_watermark = $this->exists($param,'watermark')? $param['watermark'] : null;
$this->_opacity = $this->exists($param,'opacity')? $param['opacity'] : 75;
$this->_gravity = $this->exists($param,'gravity')? $param['gravity'] : 'SouthEast';
$this->_geometry = $this->exists($param,'geometry')? $param['geometry'] : '+10+10';
$this->_croppos = $this->exists($param,'croppos')? $param['croppos'] : 'TL';
$this->_bgcolor = $this->exists($param,'bgcolor')? $param['bgcolor'] : null;
$this->_quality = $this->exists($param,'quality')? $param['quality'] : 90;
$this->_width = $this->exists($param,'width')? $param['width'] : null;
$this->_height = $this->exists($param,'height')? $param['height'] : null;
}

/** 创建缩略图

• @param String $source 原图

• @param String $dest 目标图

• @return boolean
  */
  public function create_thumb($source,$dest){
  // 检查使用的handler是否已安装
  if(!$this->check_handler()){
  $this->to_log('handler not installed');
  return false;
  }
  // 判断区域宽高是否正确
  if(!is_numeric($this->_width) || !is_numeric($this->_height) || $this->_width<=0 || $this->_height<=0){
  $this->to_log('width or height invalid');
  return false;
  }

  // 判断源文件是否存在
  if(!file_exists($source)){
  $this->to_log($source.' not exists');
  return false;
  }

  // 创建目标文件路径
  if(!$this->create_dirs($dest)){
  $this->to_log(dirname($dest).' create fail');
  return false;
  }

  $this->_source = $source; // 源文件
  $this->_dest = $dest; // 目标文件

  // 处理图片
  switch($this->_type){
  case 'fit':
  if($this->_handler=='imagemagick'){
  return $this->fit();
  }else{
  return $this->gd_fit();
  }
  break;

  case 'crop':
  if($this->_handler=='imagemagick'){
  return $this->crop();
  }else{
  return $this->gd_crop();
  }
  break;

  default:
  $this->to_log($this->_type.' not fit and crop');
  return false;
  }
  }

/** 按比例压缩或拉伸图片

• @return boolean
  */
  private function fit(){

  // 判断是否填充背景
  $bgcolor = ($this->_bgcolor!=null)?
  sprintf(" -background '%s' -gravity center -extent '%sx%s' ",$this->_bgcolor,$this->_width,$this->_height) : "";

  // 判断是否要转为RGB
  $source_info = getimagesize($this->_source);
  $colorspace = (!isset($source_info['channels']) || $source_info['channels']!=3)? ' -colorspace RGB ' : '';

  // 命令行
  $cmd = sprintf("convert -resize '%sx%s' '%s' %s -quality %s %s '%s'",$this->_height,$this->_source,$bgcolor,$this->_quality,$colorspace,$this->_dest);

  // 记录执行的命令
  $this->to_log($cmd);

  // 执行命令
  exec($cmd);

  // 添加水印
  $this->add_watermark($this->_dest);

  return is_file($this->_dest)? true : false;
  }

/** 裁剪图片

• @return boolean
  */
  private function crop(){
  // 获取生成的图片尺寸
  list($pic_w,$pic_h) = $this->get_size();

  // 获取截图的偏移量
  list($offset_w,$offset_h) = $this->get_crop_offset($pic_w,$pic_h);

  // 判断是否要转为RGB
  $source_info = getimagesize($this->_source);
  $colorspace = (!isset($source_info['channels']) || $source_info['channels']!=3)? ' -colorspace RGB ' : '';

  // 命令行
  $cmd = sprintf("convert -resize '%sx%s' '%s' -quality %s %s -crop %sx%s+%s+%s +repage '%s'",$pic_w,$pic_h,$offset_w,$offset_h,$this->_dest);

  // 记录执行的命令
  $this->to_log($cmd);

  // 执行命令
  exec($cmd);

  // 添加水印
  $this->add_watermark($this->_dest);

  return is_file($this->_dest)? true : false;
  }

/** GD库按比例压缩或拉伸图片

• @return boolean
  */
  private function gd_fit(){
  // 获取生成的图片尺寸
  list($pic_w,$pic_h) = $this->get_size();

  list($owidth,$oheight,$otype) = getimagesize($this->_source);

  switch($otype){
  case 1: $source_img = imagecreatefromgif($this->_source); break;
  case 2: $source_img = imagecreatefromjpeg($this->_source); break;
  case 3: $source_img = imagecreatefrompng($this->_source); break;
  default: return false;
  }

  // 按比例缩略/拉伸图片
  $new_img = imagecreatetruecolor($pic_w,$pic_h);
  imagecopyresampled($new_img,$source_img,$owidth,$oheight);

  // 判断是否填充背景
  if($this->_bgcolor!=null){
  $bg_img = imagecreatetruecolor($this->_width,$this->_height);
  $rgb = $this->hex2rgb($this->_bgcolor);
  $bgcolor =imagecolorallocate($bg_img,$rgb['r'],$rgb['g'],$rgb['b']);
  imagefill($bg_img,$bgcolor);
  imagecopy($bg_img,$new_img,(int)(($this->_width-$pic_w)/2),(int)(($this->_height-$pic_h)/2),$pic_h);
  $new_img = $bg_img;
  }

  // 获取目标图片的类型
  $dest_ext = $this->get_file_ext($this->_dest);

  // 生成图片
  switch($dest_ext){
  case 1: imagegif($new_img,$this->_dest,$this->_quality); break;
  case 2: imagejpeg($new_img,$this->_quality); break;
  case 3: imagepng($new_img,(int)(($this->_quality-1)/10)); break;
  }

  if(isset($source_img)){
  imagedestroy($source_img);
  }

  if(isset($new_img)){
  imagedestroy($new_img);
  }

  // 添加水印
  $this->add_watermark($this->_dest);

  return is_file($this->_dest)? true : false;
  }

/** GD库裁剪图片

• @return boolean
  */
  private function gd_crop(){

  // 获取生成的图片尺寸
  list($pic_w,$pic_h);

  list($owidth,$otype) = getimagesize($this->_source);

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