"how do i resize pngs with transparency in php?" Answer’s

0

From what I can tell, you need to set the blending mode to false, and the save alpha channel flag to true before you do the imagecolorallocatealpha()

<?php
/**
 * https://stackoverflow.com/a/279310/470749
 * 
 * @param resource $image
 * @param int $newWidth
 * @param int $newHeight
 * @return resource
 */
public function getImageResized($image, int $newWidth, int $newHeight) {
    $newImg = imagecreatetruecolor($newWidth, $newHeight);
    imagealphablending($newImg, false);
    imagesavealpha($newImg, true);
    $transparent = imagecolorallocatealpha($newImg, 255, 255, 255, 127);
    imagefilledrectangle($newImg, 0, 0, $newWidth, $newHeight, $transparent);
    $src_w = imagesx($image);
    $src_h = imagesy($image);
    imagecopyresampled($newImg, $image, 0, 0, 0, 0, $newWidth, $newHeight, $src_w, $src_h);
    return $newImg;
}
?>

UPDATE : This code is working only on background transparent with opacity = 0. If your image have 0 < opacity < 100 it'll be black background.

Wednesday, March 31, 2021
 
oroshnivskyy
answered 10 Months ago
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