复制代码 代码如下:

/**********************

*@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, $im, 0, 0, 0, 0, floor($newx), floor($newy), $x, $y);

return $im2;

}

这里是摘自查字典教程网之前发布的文章。更多的技巧可以参考。

收集的二十一个实用便利的PHP函数代码