PHP生成智能缩略图

<?php
class resizeimage {
	//图片类型
	var $type;

	//实际宽度
	var $width;

	//实际高度
	var $height;

	//改变后的宽度
	var $resize_width;

	//改变后的高度
	var $resize_height;

	//是否裁图
	var $cut;

	//源图象
	var $srcimg;

	//目标图象地址
	var $dstimg;

	//临时创建的图象
	var $im;

	function resizeimage($img, $wid, $hei, $c, $dstpath) {
		$this->srcimg = $img;
		$this->resize_width = $wid;
		$this->resize_height = $hei;
		$this->cut = $c;

		//图片的类型
		$this->type = strtolower ( substr ( strrchr ( $this->srcimg, "." ), 1 ) );

		//初始化图象
		$this->initi_img ();

		//目标图象地址
		$this->dst_img ( $dstpath );

		$this->width = imagesx ( $this->im );
		$this->height = imagesy ( $this->im );

		//生成图象
		$this->newimg ();
		ImageDestroy ( $this->im );
	}

	function newimg() {
		//改变后的图象的比例
		$resize_ratio = ($this->resize_width) / ($this->resize_height);
		//实际图象的比例
		$ratio = ($this->width) / ($this->height);
		if (($this->cut) == "1") //裁图
		{
			if ($ratio >= $resize_ratio) //高度优先
			{
				$newimg = imagecreatetruecolor ( $this->resize_width, $this->resize_height );
				imagecopyresampled ( $newimg, $this->im, 0, 0, 0, 0, $this->resize_width, $this->resize_height, (($this->height) * $resize_ratio), $this->height );
				ImageJpeg ( $newimg, $this->dstimg );
			}
			if ($ratio < $resize_ratio) //宽度优先
			{
				$newimg = imagecreatetruecolor ( $this->resize_width, $this->resize_height );
				imagecopyresampled ( $newimg, $this->im, 0, 0, 0, 0, $this->resize_width, $this->resize_height, $this->width, (($this->width) / $resize_ratio) );
				ImageJpeg ( $newimg, $this->dstimg );
			}
		} else //不裁图
		{
			if ($ratio >= $resize_ratio) {
				$newimg = imagecreatetruecolor ( $this->resize_width, ($this->resize_width) / $ratio );
				imagecopyresampled ( $newimg, $this->im, 0, 0, 0, 0, $this->resize_width, ($this->resize_width) / $ratio, $this->width, $this->height );
				ImageJpeg ( $newimg, $this->dstimg );
			}
			if ($ratio < $resize_ratio) {
				$newimg = imagecreatetruecolor ( ($this->resize_height) * $ratio, $this->resize_height );
				imagecopyresampled ( $newimg, $this->im, 0, 0, 0, 0, ($this->resize_height) * $ratio, $this->resize_height, $this->width, $this->height );
				ImageJpeg ( $newimg, $this->dstimg );
			}
		}
	}

	//初始化图象
	function initi_img() {
		if ($this->type == "jpg") {
			$this->im = imagecreatefromjpeg ( $this->srcimg );
		}
		if ($this->type == "gif") {
			$this->im = imagecreatefromgif ( $this->srcimg );
		}
		if ($this->type == "png") {
			$this->im = imagecreatefrompng ( $this->srcimg );
		}
	}

	//图象目标地址
	function dst_img($dstpath) {
		$full_length = strlen ( $this->srcimg );
		$type_length = strlen ( $this->type );
		$name_length = $full_length - $type_length;
		$name = substr ( $this->srcimg, 0, $name_length - 1 );
		$this->dstimg = $dstpath;

		//echo $this->dstimg;
	}
}
$resizeimage = new resizeimage ( "11.jpg", "200", "150", "1", "17.jpg" );
?>