PHP校验码生成--备忘
<?php session_start();//保存生成值,以与用户输入比较//-------------------------------------$img_w = 80;// 设置图片宽$img_h = 20;// 设置图片高$pixel_num = 200;//点越多干扰越大$is_set_line = true;// 启用干扰线$pixel_mode = 2;// 干扰点模式,1,同色;2，杂色//-------------------------------------// 随机数产生器function make_seed(){ list($usec, $sec) = explode(' ', microtime()); return (float) $sec + ((float) $usec * 100000);}mt_srand(make_seed());//4.2.0以下版本适用$authnum = mt_rand(100, 99999);// 加入session$_SESSION['verifycode']=$authnum;//echo $authnum;//生成验证码图片Header("Content-type: image/PNG");$im = imagecreatetruecolor($img_w, $img_h);$bg_color = ImageColorAllocate($im, mt_rand(250,255),mt_rand(250,255),mt_rand(250,255));// 绘制背景imagefill($im,0,0,$bg_color);$total_width = 0;$word_info = array();// 循环，获取文字信息$word_length = strlen($authnum);for($ii=0; $ii<$word_length; $ii++){ $word_space = mt_rand(1,5); $font = rand(3,5); mt_rand(1,9)%2 == 0?$top = 1:$top = 3; $word_info[$ii]['char'] = substr($authnum,$ii,1); $word_info[$ii]['font'] = $font; $word_info[$ii]['offset'] = $top; if($ii == 0) { $word_info[$ii]['width'] = 0; } $word_info[$ii]['width'] = imageFontWidth($font)+$word_space; $word_info[$ii]['height'] = imageFontHeight($font); $word_info[$ii]['color'] = imageColorAllocate($im, mt_rand(0,50),mt_rand(0,150),mt_rand(0,200)); // 文字总宽度 $total_width += $word_info[$ii]['width']; // 取第一个字体的高度 if($ii == 0) { $total_height = imagefontHeight($font); }}// 计算偏移$offset_x = floor(($img_w - $total_width)/2);$offset_y = floor(($img_h - $total_height)/2);// 填充验证码$wid = 0;$i = 0;foreach($word_info as $key=>$val){ if($i>0) { $wid += $val['width']; } imagestring($im, $val['font'], $offset_x + $wid, $val['offset'] + $offset_y, $val['char'], $val['color']); $i++;}switch($pixel_mode){ case 1: $pixel_color = ImageColorAllocate($im, mt_rand(50,255), mt_rand(50,255), mt_rand(50,255)); // 干扰象素 for($i=0;$i<$pixel_num;$i++) { imagesetpixel($im, mt_rand()%$img_w , mt_rand()%$img_h , $pixel_color); } break; case '2': // 干扰象素for ($i=0;$i<=128;$i++) { $pixel_color = imagecolorallocate ($im, rand(0,255), rand(0,255), rand(0,255)); imagesetpixel($im,mt_rand(2,128),mt_rand(2,38),$pixel_color); } break; default: $pixel_color = ImageColorAllocate($im, mt_rand(50,255), mt_rand(50,255), mt_rand(50,255)); // 干扰象素 for($i=0;$i<$pixel_num;$i++) { imagesetpixel($im, mt_rand()%$img_w , mt_rand()%$img_h , $pixel_color); } break;}ImagePNG($im);?>