PHP创建缩略图造成图片质量低下的完美解决办法

PHP创建缩略图造成图片质量低下的完美解决办法

PHP创建缩略图造成图片质量低下的完美解决方法

1. 1. /**?
   2. *?@name?thum????缩略图函数?
   3. *?@param????sting???$img_name???图片路径?
   4. *?@param????int?????$max_width??略图最大宽度?
   5. *?@param????int?????$max_height?略图最大高度?
   6. *?@param????sting???$suffix?略图后缀(如"img_x.jpg"代表小图,"img_m.jpg"代表中图,"img_l.jpg"代表大图)?
   7. *?@return???void?
   8. */??
   9. function?thum($img_name,$max_width,$max_height,$suffix){??
   10. ????????$img_infos=getimagesize($img_name);??
   11. ????????$img_height=$img_infos[0];//图片高??
   12. ????????$img_width=$img_infos[1];//图片宽??
   13. ????????$img_extension='';//图片后缀名??
   14. ????????switch($img_infos[2]){??
   15. ????????????case?1:??
   16. ????????????????$img_extension='gif';??
   17. ????????????????break;??
   18. ????????????case?2:??
   19. ????????????????$img_extension='jpeg';??
   20. ????????????????break;??
   21. ?????????case?3:??
   22. ????????????????$img_extension='png';??
   23. ????????????????break;??
   24. ????????????default:??
   25. ????????????????$img_extension='jpeg';??
   26. ????????????????break;??
   27. ????????????}??
   28. ????????$new_img_size=get_thum_size($img_width,$img_height,$max_width,$max_height);//新的图片尺寸??
   29. ??????????
   30. ??????????
   31. ????????//print_r($new_img_size);??
   32. ????????//die('test');??
   33. ????????$img_func='';//函数名称??
   34. ????????$img_handle='';//图片句柄??
   35. ????????$thum_handle='';//略图图片句柄??
   36. ????????switch($img_extension){??
   37. ????????????case?'jpg':??
   38. ????????????????$img_handle=imagecreatefromjpeg($img_name);??
   39. ????????????????$img_func='imagejpeg';??
   40. ????????????????break;??
   41. ????????????case?'jpeg':??
   42. ????????????????$img_handle=imagecreatefromjpeg($img_name);??
   43. ????????????????$img_func='imagejpeg';??
   44. ???????????????break;??
   45. ????????????case?'png':??
   46. ????????????????$img_handle=imagecreatefrompng($img_name);??
   47. ????????????????$img_func='imagepng';??
   48. ????????????????break;??
   49. ????????????case?'gif':??
   50. ????????????????$img_handle=imagecreatefromgif($img_name);??
   51. ????????????????$img_func='imagegif';??
   52. ????????????????break;??
   53. ????????????default:??
   54. ????????????????$img_handle=imagecreatefromjpeg($img_name);??
   55. ????????????????$img_func='imagejpeg';?
   56. ????????????????break;??
   57. ????????????}??
   58. ????????/****/????
   59. ????????$quality=100;//图片质量??
   60. ????????if($img_func==='imagepng'?&&?(str_replace('.',?'',?PHP_VERSION)>=?512)){//针对php版本大于5.12参数变化后的处理情况??
   61. ????????????$quality=9;??
   62. ????????????}???
   63. ????????/****/??
   64. ????????$thum_handle=imagecreatetruecolor($new_img_size['height'],$new_img_size['width']);??
   65. ????????if(function_exists('imagecopyresampled')){??
   66. ????????????imagecopyresampled($thum_handle,$img_handle,?0,?0,?0,?0,$new_img_size['height'],$new_img_size['width'],$img_height,$img_width);??
   67. ????????????}else{??
   68. ????????????????imagecopyresized($thum_handle,$img_handle,?0,?0,?0,?0,$new_img_size['height'],$new_img_size['width'],$img_height,$img_width);??
   69. ????????????}??
   70. ????????call_user_func_array($img_func,array($thum_handle,get_thum_name($img_name,$suffix),$quality));??
   71. ????????imagedestroy($thum_handle);//清除句柄??
   72. ????????imagedestroy($img_handle);//清除句柄??
   73. ????}??
   74. ??
   75. /**?
   76. *?@name?get_thum_size?获得缩略图的尺寸?
   77. *?@param????$width??图片宽?
   78. *?@param????$height?图片高?
   79. *?@param????$max_width?最大宽度?
   80. *?@param????$maxHeight?最大高度?
   81. *?@param????array?$size;?
   82. */??
   83. function?get_thum_size($width,$height,$max_width,$max_height){??
   84. ????$now_width=$width;//现在的宽度??
   85. ????$now_height=
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