(PHP 4 >= 4.3.2, PHP 5)
imagesavealpha — Set the flag to save full alpha channel information (as opposed to single-color transparency) when saving PNG images
imagesavealpha() sets the flag to attempt to save full alpha channel information (as opposed to single-color transparency) when saving PNG images.
You have to unset alphablending (imagealphablending($im, false)), to use it.
Alpha channel is not supported by all browsers, if you have problem with your browser, try to load your script with an alpha channel compliant browser, e.g. latest Mozilla.
imagecreatetruecolor() 등의 이미지 생성 함수에서 반환한 이미지 자원.
Whether to save the alpha channel or not. Default to FALSE.
성공할 경우 TRUE를, 실패할 경우 FALSE를 반환합니다.
Example #1 imagesavealpha() example
<?php
// Load a png image with alpha channels
$png = imagecreatefrompng('./alphachannel_example.png');
// Do required operations
// Turn off alpha blending and set alpha flag
imagealphablending($png, false);
imagesavealpha($png, true);
// Output image to browser
header('Content-Type: image/png');
imagepng($png);
imagedestroy($png);
?>
Note: 이 함수는 GD 2.0.1 이상이 필요합니다. (2.0.28 이상을 권장합니다)