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GD and Image Functions
PHP Manual

# imagesavealpha

(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

### Descripción

bool imagesavealpha ( resource `$image` , bool `$saveflag` )

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.

### Lista de parámetros

`image`

  An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().

`saveflag`

  Whether to save the alpha channel or not. Default to `FALSE`.

### Valores retornados

Devuelve `TRUE` si todo se llevó a cabo correctamente, `FALSE` en caso de fallo.

### Ejemplos

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);
?>`

### Notes

> Note: Esta funcion requiere GD 2.0.1 o posterior.

### Ver también

- imagealphablending() - Set the blending mode for an image

imagerotate
imagesetbrush
GD and Image Functions
PHP Manual