php-gdHow to scale up an image

To scale images up, we use the same approach as in resizing images.

<?php

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

$imf = imagecreatetruecolor($size[0]*10,$size[1]*10);
imagealphablending($imf, false);
imagesavealpha($imf, true);
imagecopyresampled($imf, $im, 0,0,0,0, $size[0]*10,$size[1]*10,$size[0],$size[1]);

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

`/var/www/examples/small.png` path to image to scale up	`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

Usage example

<?php

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

$imf = imagecreatetruecolor($size[0]*10,$size[1]*10);
imagealphablending($imf, false);
imagesavealpha($imf, true);
imagecopyresampled($imf, $im, 0,0,0,0, $size[0]*10,$size[1]*10,$size[0],$size[1]);

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

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php-gdHow to scale up an image

Usage example

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