我有以下这个函数,可以让我调整上传的图片大小。
function resize_image($image,$width,$height,$scale)
{
list($imagewidth, $imageheight, $imageType) = getimagesize($image);
$imageType = image_type_to_mime_type($imageType);
$newImageWidth = ceil($width * $scale);
$newImageHeight = ceil($height * $scale);
$newImage = imagecreatetruecolor($newImageWidth,$newImageHeight);
switch($imageType)
{
case "image/gif":
$source = imagecreatefromgif($image);
break;
case "image/pjpeg":
case "image/jpeg":
case "image/jpg":
$source = imagecreatefromjpeg($image);
break;
case "image/png":
case "image/x-png":
$source = imagecreatefrompng($image);
break;
}
imagecopyresampled($newImage,$source,0,0,0,0,$newImageWidth,$newImageHeight,$width,$height);
switch($imageType)
{
case "image/gif":
imagegif($newImage,$image);
break;
case "image/pjpeg":
case "image/jpeg":
case "image/jpg":
imagejpeg($newImage,$image,90);
break;
case "image/png":
case "image/x-png":
imagepng($newImage,$image);
break;
}
chmod($image, 0777);
return $image;
}
但是这个函数存在一个问题,就是当我有一个带透明背景的png或gif时,它不能创建透明度。
我该如何修复这个函数以允许php使用透明度?