php实现图片按比例截取的方法

filename = 'img/test.jpg';$all_type = array("jpg"  => array("create"=>"ImageCreateFromjpeg", "output"=>"imagejpeg"  , "exn"=>".jpg"),"gif"  => array("create"=>"ImageCreateFromGIF" , "output"=>"imagegif"  , "exn"=>".gif"),"jpeg"  => array("create"=>"ImageCreateFromjpeg", "output"=>"imagejpeg"  , "exn"=>".jpg"),"png"  => array("create"=>"imagecreatefrompng" , "output"=>"imagepng"  , "exn"=>".png"),"wbmp"  => array("create"=>"imagecreatefromwbmp", "output"=>"image2wbmp" , "exn"=>".wbmp"));$imgtype = getimagesize($filename);$width = $imgtype[0];$height = $imgtype[1];$type = str_replace('image/','',$imgtype['mime']);$func_create = $all_type[$type]['create'];$func_output = $all_type[$type]['output'];$x = $y =0;if(($width * 100)>($height * 120)){$newwidth = ceil($height * 120/100);$newheight = $height;$x = ($width-$newwidth)/2;}elseif(($width * 100)<($height * 120)){$newheight = ceil($width * 100/120);$newwidth = $width;$y = ($height-$newheight)/2;}else{$newheight = $height;$newwidth = $width; }// Load$thumb = imagecreatetruecolor($newwidth, $newheight);$source = $func_create($filename);// Resizeimagecopyresized($thumb, $source, 0, 0, 0, 0, $newwidth, $newheight, $newwidth, $newheight);// Output$func_output($thumb,'a.jpeg');