Imagick::getImageAlphaChannel

(PECL imagick 2 >= 2.3.0, PECL imagick 3)

Imagick::getImageAlphaChannel — Checks if the image has an alpha channel

Descrizione

public Imagick::getImageAlphaChannel(): bool

Returns whether the image has an alpha channel.

Elenco dei parametri

Questa funzione non contiene parametri.

Valori restituiti

Returns true if the image has an alpha channel value and false if not, i.e. the image is RGB rather than RGBA or CMYK rather than CMYKA.

Errori/Eccezioni

Lancia una ImagickException in caso di errore.

Log delle modifiche

Versione	Descrizione
PECL imagick 3.6.0	Returns a bool now; previously, an int was returned.

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User Contributed Notes 1 note

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phroggar ¶

2 years ago

You want to check wether an image has an alpha channel? But you have no control which Imagick Version is used?

Background: 

Method available since ImageMagick 6.4.0
Method returns boolean instead of int since 6.9.x

Example:

$image= new Imagick();
$image->readImage($source_file);

$imageHasAlphaChannel = (method_exists($image, 'getImageAlphaChannel') && ($document->getImageAlphaChannel() === \Imagick::ALPHACHANNEL_ACTIVATE || $document->getImageAlphaChannel()  === true));

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