本文实例讲述了php使用GD创建保持宽高比缩略图的方法。分享给大家供大家参考。具体如下：
/**
* Create a thumbnail image from $inputFileName no taller or wider than
* $maxSize. Returns the new image resource or false on error.
* Author: mthorn.net
*/
function thumbnail($inputFileName, $maxSize = 100)
{
$info = getimagesize($inputFileName);
$type = isset($info['type']) ? $info['type'] : $info[2];
// Check support of file type
if ( !(imagetypes() & $type) )
{
// Server does not support file type
return false;
}
$width = isset($info['width']) ? $info['width'] : $info[0];
$height = isset($info['height']) ? $info['height'] : $info[1];
// Calculate aspect ratio
$wRatio = $maxSize / $width;
$hRatio = $maxSize / $height;
// Using imagecreatefromstring will automatically detect the file type
$sourceImage = imagecreatefromstring(file_get_contents($inputFileName));
// Calculate a proportional width and height no larger than the max size.
if ( ($width
希望本文所述对大家的php程序设计有所帮助。