PHP thumbnail with white background and not centralized - php

Question

I have the following php script to create thumbnail after uploading an image. It is working properly, but it creates a black background and does not center the image if it is not the size you want, does anyone know how to leave the white background and center it?
How to fix it
https://imgur.com/a/uTrPadZ
if($_SERVER['REQUEST_METHOD']=='POST')
{
$filetmp = $_FILES["image"]["tmp_name"];
$filename = $_FILES["image"]["name"];
$filetype = $_FILES["image"]["type"];
$filesize = $_FILES["image"]["size"];
$fileinfo = getimagesize($_FILES["image"]["tmp_name"]);
$filewidth = $fileinfo[0];
$fileheight = $fileinfo[1];
$filepath = "../uploads/";
$filepath_thumb = "../thumbnail/";
if($filetmp == "")
{
echo "please select a photo";
}
else
{
if($filesize > 2097152)
{
echo "photo > 2mb";
}
else
{
if($filetype != "image/jpeg" && $filetype != "image/png" && $filetype != "image/gif")
{
echo "Please upload jpg / png / gif";
}
else
{
$final_image = rand(1000,1000000).$filename;
$filepath = $filepath.strtolower($final_image);
move_uploaded_file($filetmp,$filepath);
if($filetype == "image/jpeg")
{
$imagecreate = "imagecreatefromjpeg";
$imageformat = "imagejpeg";
}
if($filetype == "image/png")
{
$imagecreate = "imagecreatefrompng";
$imageformat = "imagepng";
}
if($filetype == "image/gif")
{
$imagecreate= "imagecreatefromgif";
$imageformat = "imagegif";
}
$new_width = "200";
$new_height = "200";
$filepath_thumb = $filepath_thumb.strtolower($final_image);
$image_p = imagecreatetruecolor($new_width, $new_height);
$image = $imagecreate($filepath); //photo folder
if($filewidth > $fileheight)
{
$thumb_w = $new_width;
$thumb_h = $fileheight*($new_height/$filewidth);
}
if($filewidth < $fileheight)
{
$thumb_w = $filewidth*($new_width/$fileheight);
$thumb_h = $new_height;
}
if($filewidth == $fileheight)
{
$thumb_w = $new_width;
$thumb_h = $new_height;
}
$dst_img = ImageCreateTrueColor($thumb_w,$thumb_h);
imagecopyresampled($image_p,$image,0,0,0,0,$thumb_w,$thumb_h,$filewidth,$fileheight);
$imageformat($image_p, $filepath_thumb);//thumb folder
}
}
}
}

Answer 1

Black is the default background, you just have to set the background colour of the new image to white first.
//set background colour white before copying
$white = imagecolorallocate($image_p, 255, 255, 255);
imagefill($image_p, 0, 0, $white);
imagecopyresampled($image_p,$image,0,0,0,0,$thumb_w,$thumb_h,$filewidth,$fileheight);
$imageformat($image_p, $filepath_thumb);//thumb folder
Also, $dst_img doesn't appear to be used.
Centering (untested, but simple enough math):
$xOffset = (imagesx($p_image)-$thumb_w) / 2;
$yOffset = (imagesy($p_image)-$thumb_h) / 2;
imagecopyresampled($image_p,$image,$offsetX,$offsetY,0,0,$thumb_w,$thumb_h,$filewidth,$fileheight);
If you know which dimension does not match the new thumbnail dimension this could be simplified.