PHP generated captcha picture does not show problems _php tutorial

Today in doing a PHP verification code program found that the generated pictures do not appear, and began to think that PHP GD library is not open, check with Phpinfo is open ah, the following small series to introduce this problem solution.

Clear the BOM, the code is also the top line to start writing, GD Library is also open, from here to look at the estimate is not the problem of GD library, may be in the code of the program.

Code to generate the verification code:

The code is as follows

Copy Code

/* * Verification Code Generation Program */ $letter = "; Get random numbers for ($i =0; $i <2; $i + +) { $letter. = Chr (Mt_rand (48,57)); } Get random letters for ($i =0; $i <2; $i + +) { $letter. = Chr (Mt_rand (65,90)); } Refactoring character Order $strs = Str_split ($letter); Shuffle ($STRS); $rndstring = ""; while (list (, $str) = each ($strs)) { $rndstring. = $str; } If GD is supported, the drawing if (function_exists ("Imagecreate")) { Write cookies to the browser Setcookie ("Zjs_ckstr", MD5 (Strtolower ($rndstring)), Time () +300, '/');//Verification code valid for 5 minutes $rndcodelen = strlen ($rndstring); Picture size $im = Imagecreate (100,30); $im = Imagecreatefromgif ("Code.gif"); Font $font _type = dirname (dirname (__file__)). " /data/font/avantgardebookbt.ttf "; Background color $backcolor = Imagecolorallocate ($im, 255,255,255); Font Color Imagettftext not supported $fontColor = Imagecolorallocate ($im, 0,0,0); Support Imagettftext $fontColor 2 = imagecolorallocate ($im, 0,0,0); Shadow $fontColor 1 = imagecolorallocate ($im, 255,255,25); Add background clutter $pixColor = Imagecolorallocate ($im, 199, 199, 199);//Miscellaneous color for ($j =0; $j <1000; $j + +) { Imagesetpixel ($im, Rand (0,100), Rand (0,30), $pixColor); } Add a background line for ($j =0; $j <=3; $j + +) { Background Line Color $lineColor 1 = imagecolorallocate ($im, rand (0, 255), rand (0, 255), rand (0, 255)); Background line direction size Imageline ($im, Rand (0,40), Rand (3,25), Rand (40,88), Rand (3,25), $lineColor 1); } $strposs = Array (); Text for ($i =0; $i < $rndcodelen; $i + +) { if (function_exists ("Imagettftext")) { $strposs [$i][0] = $i *16+17;//x axis $strposs [$i][1] = Mt_rand (20,23);//y axis Imagettftext ($im, 5, 5, $strposs [$i][0]+1, $strposs [$i][1]+1, $fontColor 1, $font _type, $rndstring [$i]); } else{ Imagestring ($im, 5, $i *16+7, Mt_rand (2, 4), $rndstring [$i], $fontColor); } } Text for ($i =0; $i < $rndcodelen; $i + +) { if (function_exists ("Imagettftext")) { Imagettftext ($im, 16,5, $strposs [$i][0]-1, $strposs [$i][1]-1, $fontColor 2, $font _type, $rndstring [$i]); } } Header ("Pragma:no-cachern"); Header ("Cache-control:no-cachern"); Header ("Expires:0rn"); Output a specific type of picture format, with a priority of GIF-, JPG if (function_exists ("Imagegif")) { Header ("CONTENT-TYPE:IMAGE/GIFRN"); Imagegif ($im); }else{ Header ("Content-type:image/jpegrn"); Imagejpeg ($im); } Imagedestroy ($im); } ?>

Feeling is not no problem, and then Baidu found a man said the key is to join the Ob_clean, this let me think of the reason.

Solutions

Ob_clean (); Key code to prevent the ' image cannot be displayed because of its own error '.

Before the header output is added

The code is as follows	Copy Code
Header (' content-type:image/png ');

http://www.bkjia.com/PHPjc/633063.html www.bkjia.com true http://www.bkjia.com/PHPjc/633063.html techarticle today in doing a PHP verification code program found that the generated pictures do not appear, began to think that PHP GD library is not open, check with phpinfo is open, ah, the following small series to everyone ...

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