放大和截取图片

1、
$image = "oldimg.PNG"; // 原图
$imgstream = file_get_contents($image);
$im = imagecreatefromstring($imgstream);
$x = imagesx($im);
$y = imagesy($im);

//放大200%,缩小雷同
$thumbw = $x*2; // 期望的目标图宽
$thumbh = $y*2; // 期望的目标图高

if(function_exists("imagecreatetruecolor"))
  $dim = imagecreatetruecolor($thumbw, $thumbh); // 创建目标图gd2
else
  $dim = imagecreate($thumbw, $thumbh); // 创建目标图gd1
imagecopyresized ($dim,$im,0,0,0,0,$thumbw,$thumbh,$x,$y);

header ("Content-type: image/jpeg");
imagejpeg ($dim);
?>
2、
$image = "oldimg.PNG"; // 原图
$imgstream = file_get_contents($image);
$im = imagecreatefromstring($imgstream);
$x = imagesx($im);
$y = imagesy($im);

$thumbw = 50; // 期望的目标图宽
$thumbh = 30; // 期望的目标图高

if(function_exists("imagecreatetruecolor"))
  $dim = imagecreatetruecolor($thumbw, $thumbh); // 创建目标图gd2
else
  $dim = imagecreate($thumbw, $thumbh); // 创建目标图gd1
imagecopyresized ($dim,$im,0,0,10,10,$thumbw,$thumbh,$thumbw,$thumbh);

header ("Content-type: image/jpeg");
imagejpeg ($dim);
?>