PHP numbers and number operation verification code

This article mainly introduces PHP numbers and number operation verification codes. Interested friends can refer to it. I hope it will be helpful to everyone.

The details are as follows:

1. Numeric verification code:

<?php //第一个实例是数字验证码，最常见的验证码。多少个数字可以由自己决定。
//$num是生成的验证码包含几个数字
getValidate(4,60,20);
function getValidate($num,$w,$h){
  $code = "";
  for($i=0;$i<$num;$i++){
    $code .= rand(0,9);
  }
  //code变量最后是$num个数字，并且是字符串。因袭如果是生成四位的数字验证码，可以用rand(1000,9999)生成
  Header("Content-type:image/PNG");
  $img = imagecreate($w,$h);//创建图片，长宽参数是一开始定义好的。
  $black = imagecolorallocate($img,0,0,0);//定义黑色
  $gray = imagecolorallocate($img,200,200,200);//定义灰色
  $bgcolor = imagecolorallocate($img,255,255,255);//背景色白色
  imagefill($img,0,0,$gray);
  //imagefill($image,ing $x,int $y,int $color),在image图像的坐标x,y处用color颜色执行区域填充
  //给验证码画上边框，感觉验证码美美的,其实呢画边框就是给他画上一个矩形
  imagerectangle($img,0,0,$w-1,$h-1,$black);//用黑色的框框
  /*imagestring($image,$font,$x,$y,$s,$col)
  用col颜色将字符串s画到image所代表的图像的x,y处（xy是字符串的左上角坐标），
  整幅图像的左上角为(0,0)如果font是1，2，3，4，5则使用内置字体*/
  //一下是画四个数字的方法，让四个字符位置都随机等
  $strx = rand(5,10);
  for($i = 0;$i < $num;$i++){
    $strops = rand(1,6);
    imagestring($img,5,$strx,$strops,substr($code,$i,1),$black);
    $strx += rand(8,12);
    //strx是横坐标，需要每一次加上之前的坐标，保证不会重叠。纵坐标不管
  }
  //substr() 函数返回字符串的一部分,substr(string,start,length),要截取的字符串，start开始位置，length截取的长度
  //生成好了数字，下面要给验证码区域一些干扰，防止一些工具可以自动识别
  //1.方法一：给背景加上很多噪点
  //imagesetpixel($image,$x,$y,$color),在image图像中用color颜色在x,y坐标(图像左上角为0,0)上画一个点
  for($i = 0;$i<80;$i++){
    imagesetpixel($img, rand(0,$w), rand(0,$h), $black);//这些点分布在这个背景里面
  }
  //2.方法二：绘制几条虚线
  $style = array($black,$gray);
  imagesetstyle($img, $style);
  //imagesetstyle($image,$style),设定画线的风格，像素组成的数组
  $y1 = rand(0,$h);
  $y2 = rand(0,$h);
  $y3 = rand(0,$h);
  $y4 = rand(0,$h);
  imageline($img,0,$y1,$w,$y2,IMG_COLOR_STYLED);
  imageline($img,0,$y3,$w,$y4,IMG_COLOR_STYLED);
  imagepng($img);
  imagedestroy($img);
}
?>

2. Numerical operation verification code:

<?php getValidate(100,30);
function getValidate($w,$h){
  $img = imagecreate($w,$h);
  $gray = imagecolorallocate($img,255,255,255);
  $black = imagecolorallocate($img,rand(0,200),rand(0,200),rand(0,200));
  $red = imagecolorallocate($img, 255, 0, 0);
  $white = imagecolorallocate($img, 255, 255, 255);
  $green = imagecolorallocate($img, 0, 255, 0);
  $blue = imagecolorallocate($img, 0, 0, 255);
  imagefilledrectangle($img, 0, 0, 100, 30, $black);
  for($i = 0;$i < 80;$i++){
    imagesetpixel($img, rand(0,$w), rand(0,$h), $gray);
  }
  $num1 = rand(1,99);
  $num2 = rand(1,99);
  imagestring($img, 5, 5, rand(1,10), $num1, $red);
  imagestring($img,5,30,rand(1,10),getRand(), $white);
  imagestring($img,5,45,rand(1,10),$num2, $green);
  imagestring($img,5,65,rand(1,10),"=", $blue);
  imagestring($img,5,80,rand(1,10),"?", $red);
  header("content-type:image/png");
  imagepng($img);
  imagedestroy($img);
}
function getRand(){
  $code = rand(0,1);
  switch ($code) {
    case 0:
      return "+";
      break;
    case 1:
      return "-";
      break;
    default:
      # code...
      break;
  }
}
?>

Summary: The above is the entire content of this article, I hope it will be helpful to everyone's study.

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