php生成验证码
$im = imagecreatetruecolor(100, 40);
$white = imagecolorallocate($im,255, 255, 0);
imagefill($im, 0, 0, $white);
$color = imagecolorallocate($im, 0, 255, 255);
imagerectangle($im, 1, 1,99,39, $color);
$arr = "123456789asdfghjkertyuzxcvbnm";
//echo strlen($arr);
for($i = 0;$i<4;$i++){
$char = $arr[rand(0,29)];
$col = imagecolorallocate($im,rand(0,120),rand(0,120), rand(0,120));
$x = ($i*100/4)+rand(5,10);
$y = rand(10,20);
imagestring ($im, 5, $x, $y ,$char, $col );
}
for($i = 0;$i<200;$i++){
$x = rand(1,99);
$y = rand(1,39);
$c = imagecolorallocate($im,rand(0,120),rand(0,120), rand(0,120));
imagesetpixel($im,$x,$y,$c);
}
for ($i=0; $i < 3; $i++) {
$x1 = rand(1,99);
$y1 = rand(1,39);
$x2 = rand(1,99);
$y2 = rand(1,39);
$c = imagecolorallocate($im,rand(0,120),rand(0,120), rand(0,120));
imageline ($im, $x1 , $y1 , $x2 , $y2 , $c );
}
header("content-type:image/jpg");
imagejpeg($im);
imagedestroy($im);