基于PHP实现等比压缩图片大小

<?php$im = imagecreatefromjpeg('D:/phpplace/.jpeg');resizeImage($im,,,'xinde','.jpg');function resizeImage($im,$maxwidth,$maxheight,$name,$filetype){$pic_width = imagesx($im);$pic_height = imagesy($im);echo "start-----------------" ;if(($maxwidth && $pic_width > $maxwidth) && ($maxheight && $pic_height > $maxheight)){if($maxwidth && $pic_width>$maxwidth){$widthratio = $maxwidth/$pic_width;$resizewidth_tag = true;}if($maxheight && $pic_height>$maxheight){$heightratio = $maxheight/$pic_height;$resizeheight_tag = true;}if($resizewidth_tag && $resizeheight_tag){if($widthratio<$heightratio)$ratio = $widthratio;else$ratio = $heightratio;}if($resizewidth_tag && !$resizeheight_tag)$ratio = $widthratio;if($resizeheight_tag && !$resizewidth_tag)$ratio = $heightratio;$newwidth = $pic_width * $ratio;$newheight = $pic_height * $ratio;if(function_exists("imagecopyresampled")){$newim = imagecreatetruecolor($newwidth,$newheight);imagecopyresampled($newim,$im,,,,,$newwidth,$newheight,$pic_width,$pic_height);}else{$newim = imagecreate($newwidth,$newheight);imagecopyresized($newim,$im,,,,,$newwidth,$newheight,$pic_width,$pic_height);}$name = $name.$filetype;imagejpeg($newim,$name);imagedestroy($newim);}else{$name = $name.$filetype;imagejpeg($im,$name);} }