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How to use PHP GD library to generate verification code _php tutorial

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Author: User
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When we want to useAdd a line to the php.ini first: Extension=php_gd2.dll

Restart Apache. Make a test page var_dump (Gd_info ()); The output data indicates that the PHP GD Library Reference was successful.

Form auth.html

 
 
    
  
  
  1. 
  
  2.  <html>   
    3. 
  
  
  3. 
  
  4.  <head>   
    5. 
  
  
  5. 
  
  6. < Meta    http-equiv='content-type '   Content=' text/ html Charset=utf-8 '>  
    7. 
  
  
  7. 
  
  8. < title >  Verification Code   title>   
    9. 
  
  
  9. 
  
  10.   head>   
    11. 
  
  
  11. 
  
  12.  <body>   
    13. 
  
  
  13. 
  
  14. < H1 >  Please enter a verification code   H1>   
    15. 
  
  
  15. 
  
  16. < form    action="check_auth.php"   method= "POST" >  
    17. 
  
  
  17. 
  
  18.  < input    name="auth"   type="text">  
    19. 
  
  
  19. 
  
  20.  < img    src="auth.php"   border="0"    />  
    21. 
  
  
  21. 
  
  22.  < input    type= " submit" value="commit">  
    23. 
  
  
  23. 
  
  24.   form>   
    25. 
  
  
  25. 
  
  26.   body>   
    27. 
  
  
  27. 
  
  28.   html>   
    29.

PHP GD Library generated verification code auth.php

 
 
    
  
  
  1. 
  
  2.   php   
    3. 
  
  
  3. 
  
  4. Session_Start ();
    5. 
  
  
  5. 
  
  6. Header ("Content-type:image/png");
    7. 
  
  
  7. 
  
  8. 
  
  
  9. 
  
  10.  $ Img_width =  - ; 
    11. 
  
  
  11. 
  
  12.  $ Img_height =  - ; 
    13. 
  
  
  13. 
  
  14. 
  
  
  15. 
  
  16. Srand (Microtime () *100000);
    17. 
  
  
  17. 
  
  18. For ($i=0; $i<4; $i + +)
    19. 
  
  
  19. 
  
  20. {
    21. 
  
  
  21. 
  
  22.  $ New_number. = Dechex (rand (0,15)); 
    23. 
  
  
  23. 
  
  24. }
    25. 
  
  
  25. 
  
  26. 
  
  
  27. 
  
  28. $_session[check_auth]= $new _number;
    29. 
  
  
  29. 
  
  30.  $ New_number = imagecreate ($img _width, $img _height);//Create an image
    31. 
  
  
  31. 
  
  32. Imagecolorallocate ($new _number,255,255,255); Set the background color to white
    33. 
  
  
  33. 
  
  34. 
  
  
  35. 
  
  36. For ($i=0; $i<strlen($_session[ Check_auth]); $i + +)
    37. 
  
  
  37. 
  
  38. {
    39. 
  
  
  39. 
  
  40.  $ Font = Mt_rand (3,5); 
    41. 
  
  
  41. 
  
  42.  $ x = Mt_rand (1,8) + $img _width* $i/4; 
    43. 
  
  
  43. 
  
  44.  $ y = Mt_rand (1, $img _HEIGHT/4); 
    45. 
  
  
  45. 
  
  46.  $ Color = imagecolorallocate ($new _number,mt_rand (0,100), Mt_rand (0,150), Mt_rand (0,200));//Set character color
    47. 
  
  
  47. 
  
  48. Imagestring ($new _number, $font, $x, $y, $_session[check_auth][$i], $color);//Output character
    49. 
  
  
  49. 
  
  50. }
    51. 
  
  
  51. 
  
  52. 
  
  
  53. 
  
  54. Imagepng ($new _number);
    55. 
  
  
  55. 
  
  56. Imagedestroy ($new _number);
    57. 
  
  
  57. 
  
  58. ?>  
    59.

PHP GD Library Submission page check_auth.php

 
 
    
  
  
  1. 
  
  2.   php   
    3. 
  
  
  3. 
  
  4. Session_Start ();
    5. 
  
  
  5. 
  
  6.  $ Auth =$_post[' auth ']; 
    7. 
  
  
  7. 
  
  8. 
  
  
  9. 
  
  10. if (empty ($auth))
    11. 
  
  
  11. 
  
  12. {
    13. 
  
  
  13. 
  
  14. Echo ' ERROR: The verification code cannot be empty ';
    15. 
  
  
  15. 
  
  16. Die
    17. 
  
  
  17. 
  
  18. }
    19. 
  
  
  19. 
  
  20. 
  
  
  21. 
  
  22. if ($auth==$_session[' Check_auth '))
    23. 
  
  
  23. 
  
  24. {
    25. 
  
  
  25. 
  
  26. Echo ' right ';
    27. 
  
  
  27. 
  
  28. }
    29. 
  
  
  29. 
  
  30. Else
    31. 
  
  
  31. 
  
  32. {
    33. 
  
  
  33. 
  
  34. Echo ' ERROR: Verification code input error ';
    35. 
  
  
  35. 
  
  36. }
    37. 
  
  
  37. 
  
  38. ?>  
    39.

The above is the introduction of the PHP GD library generated verification code related knowledge, we hope to help.


http://www.bkjia.com/PHPjc/446427.html www.bkjia.com true http://www.bkjia.com/PHPjc/446427.html techarticle when we want to use first add a line in php.ini: Extension=php_gd2.dll restart Apache. Make a test page var_dump (Gd_info ()); The output data indicates that the PHP GD Library Reference was successful. Form ...

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