Solution to low image quality caused by creating thumbnails in PHP

* ** @ Namethum thumbnail function * @ paramsting $ img_name Image path * @ paramint $ max_width the maximum width of a thumbnail * @ paramint $ max_height the maximum height of a thumbnail * Small & quot; indicates a thumbnail ,&

/*** @ Namethum thumbnail function * @ paramsting $ img_name Image path * @ paramint $ max_width the maximum width of a thumbnail * @ paramint $ max_height the maximum height of a thumbnail * @ paramsting $ suffix the suffix of a thumbnail (for example "img_x.jpg" indicates a thumbnail, "img_m.jpg" indicates the graph, "img_l.jpg" indicates the big image. * @ returnvoid */function thum ($ img_name, $ max_width, $ max_height, $ suffix) {$ img_infos = getimagesize ($ img_name); $ img_height = $ img_infos [0]; // picture height $ img_width = $ img_infos [1]; // Picture width $ img_extension = ''; // Picture extension name switch ($ img_infos [2]) {case 1: $ img_extension = 'GIF'; break; case 2: $ img_extension = 'jpeg '; break; case 3: $ img_extension = 'PNG'; break; default: $ img_extension = 'jpeg '; break ;} $ new_img_size = get_thum_size ($ img_width, $ img_height, $ max_width, $ max_height); // New Image size // print_r ($ new_img_size ); // die ('test'); $ img_func = ''; // Function name $ img_handle =''; // Image handle $ thum_handle = ''; // skip graph image handle switch ($ img_extension) {case 'jpg ': $ img_handle = imagecreatefromjpeg ($ img_name); $ img_func = 'imagejpeg'; break; case 'jpeg ': $ img_handle = imagecreatefromjpeg ($ img_name); $ img_func = 'imagejpeg '; break; case 'PNG': $ img_handle = hour ($ img_name); $ img_func = 'imagepng '; break; case 'GIF': $ img_handle = imagecreatefromgif ($ img_name); $ img_func = 'imagegif'; break; default: $ img_handle = imagecreatefromjpeg ($ img_name ); $ img_func = 'imagejpeg '; break;}/*****/$ quality = 100; // image quality if ($ img_func === 'imagepng '& (str_replace ('. ', '', PHP_VERSION)> = 512) {// processing status after the php version is greater than 5.12 parameter change $ quality = 9 ;} /***/$ thum_handle = imagecreatetruecolor ($ new_img_size ['height'], $ new_img_size ['width']); if (function_exists ('imagecopyresampled ')) {imagecopyresampled ($ thum_handle, $ img_handle, 0, 0, 0, $ new_img_size ['height'], $ new_img_size ['width'], $ img_height, $ img_width);} else {imagecopyresized ($ thum_handle, $ img_handle, 0, 0, 0, $ new_img_size ['height'], $ new_img_size ['width'], $ img_height, $ img_width);} call_user_func_array ($ img_func, array ($ thum_handle, get_thum_name ($ img_name, $ suffix), $ quality); imagedestroy ($ thum_handle ); // clear the handle imagedestroy ($ img_handle ); // clear handle}/*** @ name get_thum_size obtain the thumbnail size * @ param $ width image width * @ param $ height image height * @ param $ max_width maximum width * @ param $ maxHeight maximum height * @ paramarray $ size; */function get_thum_size ($ width, $ height, $ max_width, $ max_height) {$ now_width = $ width; // The current width $ now_height = $ height; // the current height $ size = array (); if ($ now_width> $ max_width) {// if the current width is greater than the maximum width $ now_height * = number_format ($ max_width/$ width, 4); $ now_width = $ max_width;} if ($ now_height> $ max_height) {// if the current height is greater than the maximum height $ now_width * = number_format ($ max_height/$ now_height, 4); $ now_height = $ max_height ;} $ size ['width'] = floor ($ now_width); $ size ['height'] = floor ($ now_height); return $ size ;} /*** @ name get_thum_name get the name of the thumbnail (add _ x to the base of the larger graph) */function get_thum_name ($ img_name, $ suffix) {$ str = explode ('#', $ img_name); $ str1 = explode ('. ', $ str [1]); return $ str [0]. '_'. $ suffix. '. '. $ str1 [1];}