(PECL imagick 2.0.0)
ImagickPixel::getColor — Returns the color
$normalized = false
] )本函数还未编写文档，仅有参数列表。
Returns the color described by the ImagickPixel object, as an array. If the color has an opacity channel set, this is provided as a fourth value in the list.
normalized
Normalize the color values
An array of channel values, each normalized if TRUE is given as param. Throws
ImagickPixelException on error.
roman (2013-05-10 21:27:40)
In case you use default un-normalized getColor value the alpha value will always be either 0 or 1.
If you want to use real full-range 0-1 alpha channel on your 24bit transparent images use the alpha value from the normalized one, even if you use the rest of unnormalized data.
To copy a 24bit png with real alpha transparency, you would have to do this:
<?php
$im=new Imagick( 'image.png' );
$iterator=$im->getPixelIterator();
foreach ($iterator as $row=>$pixels) {
foreach ( $pixels as $column => $pixel ){
$un_color=$pixel->getColor(); //unnormalized color
$nor_color=$pixel->getColor(true); //normalized color
$pixel->setColor('rgba('.$un_color['r'].','.$un_color['g'].','.$un_color['b'].','.$nor_color['a'].')');
}
}
?>
If you use 'a' (alpha) value from the unnormalized color there will only be binary transparency.