PHP Generate snowflake Background captcha Code _php Tutorial

This article to introduce the PHP generated snowflake background Verification Code program codes, the need for friends to enter the reference.

Verification Code Generation Program

The code is as follows

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Session_Start (); Session_register ("Login_check_number"); Last night saw the Chianren on the Verification code effect, considered a bit, with the PHP GD library to complete similar functions First genetic the background, and then the generated verification on the stacking up $img _height=120; Define the length and width of the image first. $img _width=40; if ($HTTP _get_vars["act"]== "init") { Srand (Microtime () * 100000);//php420, Srand is not required for ($Tmpa =0; $Tmpa <4; $Tmpa + +) { $nmsg. =dechex (rand (0,15)); }//by Sports98 $HTTP _session_vars[login_check_number] = $nmsg; $HTTP _session_vars[login_check_number] = Strval (Mt_rand ("1111", "9999")); Generate 4-bit random numbers and put them in session Who can make the next addition, you can generate letters and numbers at the same time?? ----finished by Sports98. $aimg = Imagecreate ($img _height, $img _width); Create a picture Imagecolorallocate ($aimg, 255,255,255); Image background, imagecolorallocate the 1th time definition of color PHP is considered an undertone. $black = Imagecolorallocate ($aimg, 0,0,0); Define the required Black Imagerectangle ($aimg, 0,0, $img _height-1, $img _width-1, $black);//First a black rectangle surrounds the picture It's time to create a snowflake background, which is actually creating some symbols on the image. for ($i =1; $i <=100; $i + +) {//test with 100 first Imagestring ($aimg, 1,mt_rand (1, $img _height), Mt_rand (1, $img _width), "*", Imagecolorallocate ($aimg, Mt_rand (200,255) , Mt_rand (200,255), Mt_rand (200,255)); Ha, see, in fact, is not a snowflake, is to generate * number just. To make them look "disorganized, 5 6", you have to generate them in 1 1, with random numbers for their position, color, and even size, which rand () or Mt_rand can do. } The background is generated and it is time to put the random numbers that have been generated. The reason is similar to above, random number 1 1 place, at the same time let their position, size, color are used in random number ~ ~ To distinguish it from the background, the color here is not more than 200, the above is not less than 200 for ($i =0; $i Imagestring ($aimg, Mt_rand (3,5), $i * $img _height/4+mt_rand (1,10), Mt_rand (1, $img _width/2), $HTTP _session_vars[login _check_number][$i],imagecolorallocate ($aimg, Mt_rand (0,100), Mt_rand (0,150), Mt_rand (0,200)); } Header ("Content-type:image/png"); Tell the browser that the following data is a picture, not a text display Imagepng ($AIMG); Generate PNG format. Imagedestroy ($AIMG); } ?>

Validation test page

The code is as follows

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Verification Check Code if (Isset ($HTTP _post_vars["sub")): if ($HTTP _post_vars["number"]! = $HTTP _session_vars[login_check_number] | | empty ($HTTP _post_vars["number"]) { echo "Check code is incorrect!"; }else{ echo "Verification code passed! "; } endif Show_source (' test.php '); The source code of the above page Here is the source code to generate the verification code Show_source (' yanzhengma.php '); ?>

http://www.bkjia.com/PHPjc/632956.html www.bkjia.com true http://www.bkjia.com/PHPjc/632956.html techarticle This article to introduce the PHP generated snowflake background Verification Code program codes, the need for friends to enter the reference. Verification code Generator Code as follows copy code? PHP Session_star ...

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