PHP创建缩略图造成图片质量低下的完美解决办法_PHP

PHP创建缩略图造成图片质量低下的完美解决方法

1. /**?
2. [email protected]?
3. [email protected]$img_name???图片路径?
4. [email protected]$max_width??略图最大宽度?
5. [email protected]$max_height?略图最大高度?
6. [email protected]$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. [email protected]?
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. [email protected]_thum_size?获得缩略图的尺寸?
77. [email protected]$width??图片宽?
78. [email protected]$height?图片高?
79. [email protected]$max_width?最大宽度?
80. [email protected]$maxHeight?最大高度?
81. [email protected]$size;?
82. */??
83. function?get_thum_size($width,$height,$max_width,$max_height){??
84. ????$now_width=$width;//现在的宽度??
85. ????$now_height=$height;//现在的高度??
86. ????$size=array();??
87. ????if($now_width>$max_width){//如果现在宽度大于最大宽度?
88. ????????$now_height*=number_format($max_width/$width,4);??
89. ????????$now_width=?$max_width;??
90. ????????}??
91. ????if($now_height>$max_height){//如果现在高度大于最大高度??
92. ????????$now_width*=number_format($max_height/$now_height,4);??
93. ????????$now_height=$max_height;??
94. ????????}??
95. ????$size['width']=floor($now_width);??
96. ????$size['height']=floor($now_height);??
97. ????return?$size;??
98. ? ?} ??
99. /**?
100. [email protected]_thum_name?获得略图的名称(在大图基础加_x)?
101. */??
102. function?get_thum_name($img_name,$suffix){??
103. ????????$str=explode('#',$img_name);??
104. ????????$str1=explode('.',$str[1]);??
105. ????????return?$str[0].'_'.$suffix.'.'.$str1[1];??
106. ????} ?