Remote image received by CURL and reduced in PHP

Question

The code below theoretically would be to reduce the width and height of the images [JPG FORMAT ONLY] received by CURL and store on the server, but the image created is only an image in the 800x600 measures with black background, what I intended to do was only resize the images so the server would not store the original size images taken from the remote server due to the size which are large images which for the purpose have no need and would also save disk space.

$urlImg = 'https://images.site.com/image.jpg';

$url  = $urlImg;

$imgName = str_replace(":","",$url);
$imgName = str_replace("//","",$imgName);
$imgName = str_replace("/","",$imgName);
$imgName = str_replace("_","",$imgName);

$path = './upload/' . $imgName;
$curl = curl_init();
$ch   = curl_init($url);

curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

curl_setopt_array($curl, [
    CURLOPT_URL            => $url,
//  CURLOPT_BINARYTRANSFER => 1, --- No effect from PHP 5.1.3
    CURLOPT_RETURNTRANSFER => 1,
    CURLOPT_FILE           => $file,
    CURLOPT_TIMEOUT        => 50,
    CURLOPT_USERAGENT      => 'Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)'
]);

$data  = curl_exec($ch);

curl_close($ch);

$im    = imagecreatefromstring($data);

$x     = 800;
$y     = 600;

$im2   = imagecreatetruecolor($x,$y);

imagecopyresized($im2,$im,0,0,0,0,$x,$y,imagesx($im),imagesy($im));

imagecopyresampled($im2,$im,0,0,0,0,$x,$y,imagesx($im),imagesy($im));

$returnCreateImage = imagejpeg($im2, $path);

if ( $returnCreateImage ) {

    imagedestroy($im);
    imagedestroy($im2);
    echo "[Get]\n";

}

The code worked the way you wanted before the modification to reduce the images, which is this below.

$urlImg = 'https://images.site.com/image.jpg';

$url  = $urlImg;

$imgName = str_replace(":","",$url);
$imgName = str_replace("//","",$imgName);
$imgName = str_replace("/","",$imgName);
$imgName = str_replace("_","",$imgName);

$path = './upload/' . $imgName;

$curl = curl_init();

$ch = curl_init($url);

curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

// Update as of PHP 5.4 array() can be written []
curl_setopt_array($curl, [
    CURLOPT_URL            => $url,
//  CURLOPT_BINARYTRANSFER => 1, --- No effect from PHP 5.1.3
    CURLOPT_RETURNTRANSFER => 1,
    CURLOPT_FILE           => $file,
    CURLOPT_TIMEOUT        => 50,
    CURLOPT_USERAGENT      => 'Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)'
]);

$data = curl_exec($ch);

curl_close($ch);

if(file_put_contents($path, $data)) {

    echo "[Get]\n";

}

Answer 1

I believe this is because you are saving JPEG and not PNG. In theory JPEG does not support transparency, I say "in thesis" because it seems to support, but it is not so common to use such a resource.

Also, you are using the imagecreatetruecolor which creates a black image by default.

---

I don’t have PHP to test, I’m just relying on the documentation.

$original = imagecreatefromstring($data);

// Os tamanhos das imagens:
[$cx, $cy] = [800, 600];
[$ox, $oy] = [imagesx($original), imagesy($original)];

// Cria a imagem:
$comprimido = imagecreatetruecolor($cx,$cy);

// Define a imagem para transparente:
imagefill($comprimido, 0, 0, imagecolorallocatealpha($comprimido, 0, 0, 0, 127));

// Habilita a transparência:
imagealphablending($comprimido, false);
imagesavealpha($comprimido, true);

imagecopyresized($comprimido, $original, 0, 0, 0, 0, $cx, $cy, $ox, $oy);
imagecopyresampled($comprimido, $original, 0, 0, 0, 0, $cx, $cy, $ox, $oy);

// Salva como PNG (não JPEG):
$returnCreateImage = imagepng($comprimido, $path);

This should be enough, but I can’t test it. I believe that even if it doesn’t work, the problem is related to PNG.