Rechercher une fonction PHP

imagesavealpha

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(PHP 4 >= 4.3.2, PHP 5, PHP 7)

imagesavealpha — Whether to retain full alpha channel information when saving PNG images

Description

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

imagesavealpha() sets the flag which determines whether to retain full alpha channel information (as opposed to single-color transparency) when saving PNG images.

Alphablending has to be disabled (imagealphablending($im, false)) to retain the alpha-channel in the first place.

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Parameters

image

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

saveflag

Whether to save the alpha channel or not. Defaults to FALSE.

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Return Values

Returns TRUE on success or FALSE on failure.

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Examples

Example #1 Basic imagesavealpha() Usage

<?php
// Load a png image with alpha channel
$png = imagecreatefrompng('./alphachannel_example.png');

// Turn off alpha blending
imagealphablending($png, false);

// Do desired operations

// Set alpha flag
imagesavealpha($png, true);

// Output image to browser
header('Content-Type: image/png');

imagepng($png);
imagedestroy($png);
?>

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Document created the 30/01/2003, last modified the 26/10/2018
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References

  1. View the html document Language of the document:fr Manuel PHP : http://php.net

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