今天在用PHP写一个小插件的时候，遇到了一个小小的问题，就是需要将图片转换为TXT文本的内容，简单的说就是将图片转换为ASCII码，下面把代码分享给大家。

PHP 实现的将图片转换为TXT

1. <?php
2. /*
3. 2015年10月19日10:24:59
4. */
5. // 打开一幅图像
6. $file_name='d:\ascii_dora.png';
7. $chars = "$@B%8&WM#*oahkbdpqwmZO0QLCJUYXzcvunxrjft/\|()1{}[]?-_+~<>i!lI;:,\"^`'. ";
8. function getimgchars($color_tran,$chars){
9. $length = strlen($chars);
10. $alpha=$color_tran['alpha'];
11. $r=$color_tran['red'];
12. $g=$color_tran['green'];
13. $b=$color_tran['blue'];
14. $gray = intval(0.2126 * $r + 0.7152 * $g + 0.0722 * $b);
15. if($gray==0){
16. return '.';
17. }
18. if($gray<196){
19. $unit = (256.0 + 1)/$length;
20. return $chars[intval($gray/$unit)];
21. }
22. return " ";
23. }
24. function color_img($color_tran,$chars){
25. $length = strlen($chars);
26. $alpha=$color_tran['alpha'];
27. $r=$color_tran['red'];
28. $g=$color_tran['green'];
29. $b=$color_tran['blue'];
30. $gray = intval(0.2126 * $r + 0.7152 * $g + 0.0722 * $b);
31. $rand=rand (0, $length-1);
32. $color="rgb(".$r.",".$g.",".$b.")";
33. $char=$chars[$rand];
34. return '<span .$color.'" >'.$char."</span>";;
35. }
36. function resize_img($file_name,$chars,$flage=true){
37. //header('Content-Type: image/jpeg');
38. list($width, $height,$type) = getimagesize($file_name);
39. $fun='imagecreatefrom' . image_type_to_extension($type, false);
40. if($type==3){
41. $flage=false;
42. }
43. $fun($file_name);
44. $new_height =100;
45. $percent=$height/$new_height;
46. $new_width=$width/$percent;
47. $image_p = imagecreatetruecolor($new_width, $new_height);
48. $image = $fun($file_name);
49. imagecopyresampled($image_p, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);
50. if($flage){
51. return $image_p;
52. }else{
53. return $image;
54. }
55. }
56. $im=resize_img($file_name,$chars);
57. $width=imagesx($im);
58. $height=imagesy($im);
59. $back_text="";
60. for($i=1;$i<=$height;$i++){
61. for($j=1;$j<=$width;$j++){
62. $color_index = imagecolorat($im, $j-1, $i-1);
63. $color_tran = imagecolorsforindex($im, $color_index);
64. $back_text.=color_img($color_tran,$chars,false);
65. }
66. $back_text.="<br/>";
67. }
68. echo "<pre>";
69. echo $back_text;
70. echo "</pre>";
71. //file_put_contents('1.txt',$back_text);