Imagick::getImageAlphaChannel

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

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

Опис

public Imagick::getImageAlphaChannel(): bool

Returns whether the image has an alpha channel.

Параметри

У цієї функції немає параметрів.

Значення, що повертаються

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.

Помилки/виключення

Кидає ImagickException в разі помилки.

Журнал змін

Версія	Опис
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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