<?php
namespace Files;
/**
 * 生成缩略图(支持加载图片文件和字符串2种方式)
 * @param       $maxWidth       缩略图最大宽度
 * @param       $maxHeight      缩略图最大高度
 * @param       bool    $scale  是否按比例缩小，否则拉伸
 * @param       bool    $inflate        是否放大以来填充缩略图         
 */
class Thumbnail {
 
	private $maxWidth;
	private $maxHeight;
	private $scale;
	private $inflate;
	private $types;
	private $imgLoaders;
	private $imgCreators;
	private $source;
	private $sourceWidth;
	private $sourceHeight;
	private $sourceMime;
	private $thumb;
	private $thumbWidth;
	private $thumbHeight;

	public function __construct($maxWidth, $maxHeight, $scale = true, $inflate = false) {
			$this->maxWidth = $maxWidth;
			$this->maxHeight = $maxHeight;
			$this->scale = $scale;
			$this->inflate = $inflate;
			$this->types = array(
				'image/jpeg',
				'image/png',
				'image/gif'
			);
			//加载MIME类型图像的函数名称
			$this->imgLoaders = array(
				'image/jpeg'        =>      'imagecreatefromjpeg',
				'image/png'         =>      'imagecreatefrompng',
				'image/gif'         =>      'imagecreatefromgif'
			);
			//储存创建MIME类型图片的函数名称
			$this->imgCreators = array(
				'image/jpeg'        =>      'imagejpeg',
				'image/png'         =>      'imagepng',
				'image/gif'         =>      'imagegif'
			);          
	}
		
	/**
	 * 文件方式加载图片
	 * @param       string  $image 源图片
	 * @return      bool   
	 */
	public function loadFile($image){
			if(!$dims = @getimagesize($image)){
					trigger_error("源图片不存在");
			}
			if(in_array($dims['mime'], $this->types)){
					$loader = $this->imgLoaders[$dims['mime']];
					$this->source = $loader($image);
					if($dims['mime'] == 'image/png' || $dims['mime'] == 'image/gif'){
						imagesavealpha($this->source, true);
					}
					$this->sourceWidth = $dims[0];
					$this->sourceHeight = $dims[1];
					$this->sourceMime = $dims['mime'];
					$this->initThumb();
					return TRUE;
			}else{
					trigger_error('不支持'.$dims['mime']."图片类型");
			}
	}
	
	/**
	 * 字符串方式加载图片
	 * @param       string $image  字符串
	 * @param       string $mime    图片类型
	 * @return type
	 */
	public function loadData($image,$mime){
			if(in_array($mime, $this->types)){
					if($this->source = @imagecreatefromstring($image)){
							$this->sourceWidth = imagesx($this->source);
							$this->sourceHeight = imagesy($this->source);
							$this->sourceMime = $mime;
							$this->initThumb();
							return TRUE;
					}else{
							trigger_error("不能从字符串加载图片");
					}
			}else{
					trigger_error("不支持".$mime."图片格式");
			}
	}
		
	/**
	 * 生成缩略图
	 * @param       string  $file   文件名。如果不为空则储存为文件，否则直接输出到浏览器
	 */
	public function buildThumb($file = NULL){
			$creator = $this->imgCreators[$this->sourceMime];
			if(isset($file) && $this->thumb !== NULL){
					return $creator($this->thumb,$file);
			}else{
					return false;
			}
	}
	
	/**
	 * 处理缩放
	 */
	public function initThumb(){
		if($this->scale){
				if($this->sourceWidth > $this->sourceHeight){
						$this->thumbWidth = $this->maxWidth;
						$this->thumbHeight = floor($this->sourceHeight*($this->maxWidth/$this->sourceWidth));
				}elseif($this->sourceWidth < $this->sourceHeight){
						$this->thumbHeight = $this->maxHeight;
						$this->thumbWidth = floor($this->sourceWidth*($this->maxHeight/$this->sourceHeight));
				}else{
						$this->thumbWidth = $this->maxWidth;
						$this->thumbHeight = $this->maxHeight;
				}
		}
			
		if($this->sourceWidth <= $this->maxWidth && $this->sourceHeight <= $this->maxHeight && $this->inflate == FALSE){
			$this->thumb = NULL;
		}else{
			$this->thumb = imagecreatetruecolor($this->thumbWidth, $this->thumbHeight);
			if($this->sourceMime == 'image/png' || $this->sourceMime == 'image/gif')
			{
				
				imagealphablending($this->thumb, true);
				imagesavealpha($this->thumb, true);
				if($this->sourceMime == 'image/gif')
				{
					$bgcolor=imagecolorallocate($this->thumb,0,0,0); 
					$transparent = imagecolortransparent($this->thumb,$bgcolor) ;
				}
				if($this->sourceMime == 'image/png')
				{
					$transparent = imagecolorallocatealpha($this->thumb, 0, 0, 0, 127);
				}
				imagefill($this->thumb, 0, 0, $transparent);
			}
			imagecopyresampled($this->thumb, $this->source, 0, 0, 0, 0, $this->thumbWidth, $this->thumbHeight, $this->sourceWidth, $this->sourceHeight);
		}
	}
	 
	public function getMine(){
			return $this->sourceMime;
	}
	 
	public function getThumbWidth(){
			return $this->thumbWidth;
	}
	 
	public function getThumbHeight(){
			return $this->thumbHeight;
	}
		
	static function cut($source_path, $target_width, $target_height){
		$source_info   = getimagesize($source_path);
		$source_width  = $source_info[0];
		$source_height = $source_info[1];
		$source_mime   = $source_info['mime'];
		$source_ratio  = $source_height / $source_width;
		$target_ratio  = $target_height / $target_width;
	
		// 源图过高
		if ($source_ratio > $target_ratio)
		{
			$cropped_width  = $source_width;
			$cropped_height = $source_width * $target_ratio;
			$source_x = 0;
			$source_y = ($source_height - $cropped_height) / 2;
		}
		// 源图过宽
		elseif ($source_ratio < $target_ratio)
		{
			$cropped_width  = $source_height / $target_ratio;
			$cropped_height = $source_height;
			$source_x = ($source_width - $cropped_width) / 2;
			$source_y = 0;
		}
		// 源图适中
		else
		{
			$cropped_width  = $source_width;
			$cropped_height = $source_height;
			$source_x = 0;
			$source_y = 0;
		}
	
		switch ($source_mime)
		{
			case 'image/gif':
				$source_image = imagecreatefromgif($source_path);
				break;
	
			case 'image/jpeg':
				$source_image = imagecreatefromjpeg($source_path);
				break;
	
			case 'image/png':
				$source_image = imagecreatefrompng($source_path);
				break;
	
			default:
				return false;
				break;
		}
	
		$target_image  = imagecreatetruecolor($target_width, $target_height);
		$cropped_image = imagecreatetruecolor($cropped_width, $cropped_height);
	
		// 裁剪
		imagecopy($cropped_image, $source_image, 0, 0, $source_x, $source_y, $cropped_width, $cropped_height); 
		// 缩放
		imagecopyresampled($target_image, $cropped_image, 0, 0, 0, 0, $target_width, $target_height, $cropped_width, $cropped_height);
	
		header('Content-Type: image/jpeg');
		imagejpeg($target_image);
		imagedestroy($source_image);
		imagedestroy($target_image);
		imagedestroy($cropped_image);
	}//cute
 
}
 
/**
 * 缩略图类调用示例(文件)

$thumb = new Thumbnail(200, 200);
$thumb->loadFile('wap.gif');
header('Content-Type:'.$thumb->getMine());
$thumb->buildThumb();
/**
 * 缩略图类调用示例(字符串)
 
$thumb = new Thumbnail(200, 200);
$image = file_get_contents('wap.gif');
$thumb->loadData($image, 'image/jpeg');
$thumb->buildThumb('wap_thumb.gif');
 */