Php high security verification code generation project_php tutorial

Php high security verification code generation program. This generator program needs to call some font libraries. you can call some fonts that come with your system. of course, you can also put the fonts in a directory like dedecms, in this way, the local generator program on the server needs to call some fonts. you can call some fonts that come with your system. of course, you can also put the fonts in a directory like dedecms, this can also be used on the server.

The code is as follows:

Public function captcha (){ $ Font_dir = $ _ SERVER ["DOCUMENT_ROOT"]. "your_ttf_file.ttf"; // Library $ Img_w = 58; // set the image width $ Img_h = 20; // set the image height. $ Font_size = 11; // font size $ Angle_l =-10; // left angle $ Angle_r = 10; // right angle $ Code_str = "ABCDEFGHJKLMNPQRSTUVWXYZ36 "; $ Word_len = 4; // Number of digits of the verification code $ Padding = 5; // interval between two texts $ Margin = 2; // left margin $ Base_line = 15; // text baseline position $ Base_line_offset = 2; // baseline offset $ Pixel_num = 3; // the base number of vertices. $ Pixel_color = 8; // only the total number of points in the $ pixel_color color is $ pixel_num * $ pixel_color $ Noise_font_size = 1; // Miscellaneous font size $ Session_key = "my. xoyo_captcha"; // custom session key name Header ("Cache-Control: no-cache, must-revalidate "); Header ("Expires: Mon, 26 Jul 1997 05:00:00 GMT "); Header ("Pragma: no-cache "); Header ("Cache-control: private "); Header ('content-Type: image/png '); Session_start (); $ Word = ""; $ Code_str_len = strlen ($ code_str)-1; For ($ I = 0; $ I <$ word_len; $ I ++ ){ $ Word. = $ code_str [rand (0, $ code_str_len)]; } $ _ SESSION [$ session_key] = strtolower ($ word ); $ Image = imagecreatetruecolor ($ img_w, $ img_h ); Imagefilledrectangle ($ image, 0, 0, $ img_w-1, $ img_h-1, imagecolorallocate ($ image, mt_rand (235,255), mt_rand (235,255 ), mt_rand (235,255 ))); // Draw the Miscellaneous For ($ I = 0; $ I <$ pixel_color; $ I ++ ){ $ Noise_color = imagecolorallocate ($ image, mt_rand (150,225), mt_rand (150,225), mt_rand (150,225 )); For ($ j = 0; $ j <$ pixel_num; $ j ++ ){ Imagestring ($ image, $ noise_font_size, mt_rand (-10, $ img_w), mt_rand (-10, $ img_h), $ code_str [mt_rand (0, $ code_str_len)], $ noise_color ); } } // Draw text For ($ I = 0; $ I <$ word_len; ++ $ I ){ $ Color = imagecolorallocate ($ image, mt_rand (0,100), mt_rand (20,120), mt_rand (50,150 )); Imagettftext ($ image, $ font_size, mt_rand ($ angle_l, $ angle_r), $ margin, mt_rand ($ base_line-$ base_line_offset, $ base_line + $ base_line_offset), $ color, $ font, mb_substr ($ word, $ I, 1, 'utf-8 ')); $ Margin + = (imagefontwidth ($ font_size) + $ padding ); } Imagepng ($ image ); Imagedestroy ($ image ); Exit; }

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