php实现按指定大小等比缩放生成上传图片缩略图的方法

/**
?* *
?*等比缩放
?* @param unknown_type $srcImage?? 源图片路径
?* @param unknown_type $toFile???? 目标图片路径
?* @param unknown_type $maxWidth?? 最大宽
?* @param unknown_type $maxHeight? 最大高
?* @param unknown_type $imgQuality 图片质量
?* @return unknown
?*/
function resize($srcImage,$toFile,$maxWidth = 100,$maxHeight = 100,$imgQuality=100)
{
??
??? list($width,$height,$type,$attr) = getimagesize($srcImage);
??? if($width < $maxWidth? || $height < $maxHeight) return ;
??? switch ($type) {
??? case 1: $img = imagecreatefromgif($srcImage); break;
??? case 2: $img = imagecreatefromjpeg($srcImage); break;
??? case 3: $img = imagecreatefrompng($srcImage); break;
??? }
??? $scale = min($maxWidth/$width,$maxHeight/$height); //求出绽放比例
????
??? if($scale < 1) {
??? $newWidth = floor($scale*$width);
??? $newHeight = floor($scale*$height);
??? $newImg = imagecreatetruecolor($newWidth,$newHeight);
??? imagecopyresampled($newImg,$img,$newWidth,$newHeight,$width,$height);
??? $newName = "";
??? $toFile = preg_replace("/(.gif|.jpg|.jpeg|.png)/i","",$toFile);
?
??? switch($type) {
??????? case 1: if(imagegif($newImg,"$toFile$newName.gif",$imgQuality))
??????? return "$newName.gif"; break;
??????? case 2: if(imagejpeg($newImg,"$toFile$newName.jpg",$imgQuality))
??????? return "$newName.jpg"; break;
??????? case 3: if(imagepng($newImg,"$toFile$newName.png",$imgQuality))
??????? return "$newName.png"; break;
??????? default: if(imagejpeg($newImg,$imgQuality))
??????? return "$newName.jpg"; break;
??? }
??? imagedestroy($newImg);
??? }
??? imagedestroy($img);
??? return false;
}