php 调整图片尺寸的简单示例

对php调整图片尺寸的代码感兴趣的小伙伴，下面一起跟随编程之家 jb51.cc的小编两巴掌来看看吧！

/**
 * 调整图片尺寸的代码
 *
 * @param 
 * @author 网： www.jb51.cc
*@filename - path to the image
*@tmpname - temporary path to thumbnail
*@xmax - max width
*@ymax - max height
*/
function resize_image($filename,$tmpname,$xmax,$ymax)
{
	$ext = explode(.,$filename);
	$ext = $ext[count($ext)-1]; 
	if($ext == jpg || $ext == jpeg)
		$im = imagecreatefromjpeg($tmpname);
	elseif($ext == png)
		$im = imagecreatefrompng($tmpname);
	elseif($ext == gif)
		$im = imagecreatefromgif($tmpname); 
	$x = imagesx($im);
	$y = imagesy($im); 
	if($x <= $xmax && $y <= $ymax)
		return $im; 
	if($x >= $y) {
		$newx = $xmax;
		$newy = $newx * $y / $x;
	}
	else {
		$newy = $ymax;
		$newx = $x / $y * $newy;
	} 
	$im2 = imagecreatetruecolor($newx,$newy);
	imagecopyresized($im2,$im,floor($newx),floor($newy),$x,$y);
	return $im2;
}


/***   来自编程之家 jb51.cc（jb51.cc）   ***/