php-gdHow to resize transparent PNG image

<?php

$file = '/var/www/examples/clouds.png';
$size = getimagesize($file);
$im = imagecreatefrompng($file);

$w = 300;
$h = $w * $size[1] / $size[0];

$imf = imagecreatetruecolor($w, $h);
imagealphablending($imf, false);
imagesavealpha($imf, true);
imagecopyresampled($imf, $im, 0,0,0,0, $w,$h,$size[0],$size[1]);

imagePng($imf, '/tmp/image.png');ctrl + cgithub

`/var/www/examples/clouds.png` path to image to resize (has transparent background)	`getimagesize` returns image size from given path
`imagecreatefrompng` creates GD image object from given PNG image	`imagecreatetruecolor` creates true color GD image object with specified width & height
`imagealphablending` we're disabling alpha blending to prevent transparent background being converted to black color	`imagesavealpha` we're enabling alpha channel (controls transparency) for resulting image
`imagecopyresampled` resizes source image and writes result to destination image	`imagePng` saves image in PNG format to the given path

How to resize transparent PNG image, php gd

Usage example

<?php

$file = '/var/www/examples/clouds.png';
$size = getimagesize($file);
$im = imagecreatefrompng($file);

$w = 300;
$h = $w * $size[1] / $size[0];

$imf = imagecreatetruecolor($w, $h);
imagealphablending($imf, false);
imagesavealpha($imf, true);
imagecopyresampled($imf, $im, 0,0,0,0, $w,$h,$size[0],$size[1]);

imagePng($imf, '/tmp/image.png');

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php-gdHow to resize transparent PNG image

Usage example

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