How to change the size of PHP captcha font

How to change the size of PHP captcha font



[color= #0000FF] This verification code picture shows the number is too small, how to change the size of the font in the following code, the number becomes larger [/color]
Generate a Captcha picture
Header ("Content-type:image/png");
$rand = "";
for ($i =0; $i <4; $i + +) {
$rand. =dechex (rand (0,15));
}

$im = Imagecreate (100,50); Make picture background size

$black = Imagecolorallocate ($im, 0,0,0); Set of three Colors
$white = Imagecolorallocate ($im, 255,255,255);
$gray = Imagecolorallocate ($im, 200,200,200);
for ($i =0; $i <3; $i + +) {
$te =imagecolorallocate ($im, Rand (0,255), Rand (0,255), Rand (0,255));
}
Imagefill ($im, 0,0, $gray); Using area Fill method, set (0,0)

while (($rand =rand ()%100000) <10000);
Drawing a four-bit integer verification code into a picture
$_session[' rand ']= $rand;
Imagestring ($im, 5, $rand, $te);
Use the col color to draw the string s to the x, y coordinates of the image represented by the image (0, 0 in the upper-left corner).
If the font is 1,2,3,4 or 5, use the built-in font

for ($i =0; $i <200; $i + +)//Add interfering pixels
{
$randcolor = Imagecolorallocate ($im, Rand (0,255), Rand (0,255), Rand (0,255));
Imagesetpixel ($im, Rand ()%100, Rand ()%50, $randcolor);
}
Imageline ($im, 0,rand (0,100), 100,rand (0,15), $randcolor);
Imageline ($im, 0,rand (0,100), 100,rand (0,15), $randcolor);
Imageline ($im, 0,rand (0,100), 100,rand (0,15), $randcolor);
Imagepng ($im);
Imagedestroy ($im);

?>

------to solve the idea----------------------
Imagestring ($im, 5, 1-5, $rand, $te); This function uses the built-in font, which is a range of. can only be replaced by the Imagettftext () function.

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