// Example 1 - Quantum
$color = new \ImagickPixel('rgb(128, 5, 255)');
$colorRed = $color->getColorValueQuantum(\Imagick::COLOR_RED);
$colorGreen = $color->getColorValueQuantum(\Imagick::COLOR_GREEN);
$colorBlue = $color->getColorValueQuantum(\Imagick::COLOR_BLUE);
$colorAlpha = $color->getColorValueQuantum(\Imagick::COLOR_ALPHA);
return sprintf(
    "Red: %s Green: %s  Blue %s Alpha: %s",
    $colorRed,
    $colorGreen,
    $colorBlue,
    $colorAlpha
);

// Example 2
$color = new \ImagickPixel('rgba(90%, 20%, 20%, 0.75)');
$output =  "Alpha value is " . $color->getColorValue(\Imagick::COLOR_ALPHA) . "<br/>";
$output .=  "" . "<br/>";
$output .=  "Red value is " . $color->getColorValue(\Imagick::COLOR_RED) . "<br/>";
$output .=  "Green value is " . $color->getColorValue(\Imagick::COLOR_GREEN) . "<br/>";
$output .=  "Blue value is " . $color->getColorValue(\Imagick::COLOR_BLUE) . "<br/>";
$output .=  "" . "<br/>";
$output .=  "Cyan value is " . $color->getColorValue(\Imagick::COLOR_CYAN) . "<br/>";
$output .=  "Magenta value is " . $color->getColorValue(\Imagick::COLOR_MAGENTA) . "<br/>";
$output .=  "Yellow value is " . $color->getColorValue(\Imagick::COLOR_YELLOW) . "<br/>";
$output .=  "Black value is " . $color->getColorValue(\Imagick::COLOR_BLACK) . "<br/>";