php生成验证码图片学习笔记

header("Content-type:image/png");
set_time_limit(0);//设置PHP超时时间
$url = $_GET['url'];
$url = "http://vcer.***baidu.com/verify";
$imginfo = GetImageSize ( $url );
$imgw = $imginfo [0];
$imgh = $imginfo [1];
$bg = imagecreatetruecolor($imgw,$imgh);
$image = imagecreatefromjpeg($url);
imagecolorallocate($image,255,255,255);
imagecopy($bg,$image,0,0, 0,0,$imgw,$imgh);
imagedestroy($image);
ImagePng($bg);

header("Content-type:image/png");
set_time_limit(0);//设置PHP超时时间
$url = $_GET['url'];
$url = "http://vcer.***baidu.com/verify";
if(empty($url)){
echo "没有图片";
die;
}
$imginfo = GetImageSize ( $url );
$type = exif_imagetype($url);
$imgw = $imginfo [0];
$imgh = $imginfo [1];
$bg = imagecreatetruecolor($imgw,$imgh);
if($type==IMAGETYPE_GIF){
$image = imagecreatefromgif($url);
}elseif($type==IMAGETYPE_JPEG){
$image = imagecreatefromjpeg($url);
}elseif($type==IMAGETYPE_PNG){
$image = imagecreatefrompng($url);
}

imagecolorallocate($image,255,255,255);
imagecopy($bg,$image,0,0, 0,0,$imgw,$imgh);
imagedestroy($image);
ImagePng($bg);