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How to Use the php gd library to generate a verification code

Source: Internet
Author: User
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When we want to useAdd a line of reference 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 has been referenced successfully.

Table ticket auth.html

 
 
    
  
  
  1. <Html> 
    2. 
  
  
  2. <Head> 
    3. 
  
  
  3. <Meta Http-equiv='Content-type' Content='Text/html; charset = UTF-8'> 
    4. 
  
  
  4. <Title>Verification Code</Title> 
    5. 
  
  
  5. </Head> 
    6. 
  
  
  6. <Body> 
    7. 
  
  
  7. <H1>Enter Verification Code</H1> 
    8. 
  
  
  8. <Form Action="Check_auth.php" Method="Post"> 
    9. 
  
  
  9. <Input Name="Auth" Type="Text"> 
    10. 
  
  
  10. <Img Src="Auth. php" Border="0" /> 
    11. 
  
  
  11. <Input Type="Submit" Value="Submit"> 
    12. 
  
  
  12. </Form> 
    13. 
  
  
  13. </Body> 
    14. 
  
  
  14. </Html> 
    15.

Php gd library to generate Verification Code auth. php

 
 
    
  
  
  1. <?Php 
    2. 
  
  
  2. Session_start ();
    3. 
  
  
  3. Header ("Content-type: image/png ");
    4. 
  
  
  4.  
    5. 
  
  
  5. $Img_width=100;
    6. 
  
  
  6. $Img_height=20;
    7. 
  
  
  7.  
    8. 
  
  
  8. Srand (microtime () * 100000 );
    9. 
  
  
  9. For ($I=0; $ I<4; $ I ++)
    10. 
  
  
  10. {
    11. 
  
  
  11. $New_number.=Dechex(Rand (0, 15 ));
    12. 
  
  
  12. }
    13. 
  
  
  13.  
    14. 
  
  
  14. $ _ SESSION [check_auth] = $ new_number;
    15. 
  
  
  15. $New_number=ImageCreate($ Img_width, $ img_height); // create an image
    16. 
  
  
  16. ImageColorAllocate ($ new_number, 255,255,255); // set the background color to white.
    17. 
  
  
  17.  
    18. 
  
  
  18. For ($I=0; $ I<Strlen($ _ SESSION [check_auth]); $ I ++)
    19. 
  
  
  19. {
    20. 
  
  
  20. $Font=Mt_rand(3, 5 );
    21. 
  
  
  21. $X=Mt_rand(1, 8) + $ img_width * $ I/4;
    22. 
  
  
  22. $Y=Mt_rand(1, $ img_height/4 );
    23. 
  
  
  23. $Color=ImageColorAllocate($ New_number, mt_rand (0,100), mt_rand (0,150), mt_rand (0,200); // set the Character Color
    24. 
  
  
  24. ImageString ($ new_number, $ font, $ x, $ y, $ _ SESSION [check_auth] [$ I], $ color); // output character
    25. 
  
  
  25. }
    26. 
  
  
  26.  
    27. 
  
  
  27. ImagePng ($ new_number );
    28. 
  
  
  28. ImageDestroy ($ new_number );
    29. 
  
  
  29. ?> 
    30.

Php gd library submission page check_auth.php

 
 
    
  
  
  1. <?Php 
    2. 
  
  
  2. Session_start ();
    3. 
  
  
  3. $Auth= $ _ POST ['auth '];
    4. 
  
  
  4.  
    5. 
  
  
  5. If (empty ($ auth ))
    6. 
  
  
  6. {
    7. 
  
  
  7. Echo 'error: The Verification Code cannot be blank ';
    8. 
  
  
  8. Die;
    9. 
  
  
  9. }
    10. 
  
  
  10.  
    11. 
  
  
  11. If ($Auth==$ _ SESSION ['check _ auth'])
    12. 
  
  
  12. {
    13. 
  
  
  13. Echo 'true ';
    14. 
  
  
  14. }
    15. 
  
  
  15. Else
    16. 
  
  
  16. {
    17. 
  
  
  17. Echo 'error: Incorrect verification code input ';
    18. 
  
  
  18. }
    19. 
  
  
  19. ?> 
    20.

The above is the knowledge about generating verification codes in the php gd library described in this article. I hope it will be helpful to you.


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Related Keywords:
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