<?php
	function imagesResize($src,$dest,$destW,$destH) { 
		if (file_exists($src)  && isset($dest)) { 
			//取得檔案資訊
			$srcSize   = getimagesize($src); 
			$srcExtension = $srcSize[2];
			$srcRatio  = $srcSize[0] / $srcSize[1]; 
			//依長寬比判斷長寬像素
			if($srcRatio > 1){
				$destH = $destW / $srcRatio;
			}
			else{
				$destH = $destW; 
				$destW = $destW * $srcRatio;  
			}		
		}
		//建立影像 
		$destImage = imagecreatetruecolor($destW,$destH); 	

		//根據檔案格式讀取圖檔 
		switch ($srcExtension) { 
			case 1: $srcImage = imagecreatefromgif($src); break; 
			case 2: $srcImage = imagecreatefromjpeg($src); break; 
			case 3: $srcImage = imagecreatefrompng($src); break; 
		}
		//取樣縮圖 
		imagecopyresampled($destImage, $srcImage, 0, 0, 0, 0,$destW,$destH,
						   imagesx($srcImage), imagesy($srcImage)); 

		//輸出圖檔 
		switch ($srcExtension) { 
			case 1: imagegif($destImage,$dest); break; 
			case 2: imagejpeg($destImage,$dest,90); break;
			case 3: imagepng($destImage,$dest); break;
		}		
		//釋放資源
		imagedestroy($destImage);				
	}
?>