Sets the value of the specified channel of this object to the provided value, which should be between 0 and 1. This function can be used to provide an opacity channel to an ImagickPixel object.
Sets the value of the specified channel of this object to the provided value, which should be between 0 and 1. This function can be used to provide an opacity channel to an ImagickPixel object.
Parameters
colorintOne of the Imagick color constants e.g. \Imagick::COLOR_GREEN or \Imagick::COLOR_ALPHA.
valuefloatThe value to set this channel to, ranging from 0 to 1.
function setColorValue()
{
    $image = new \Imagick();
    $draw = new \ImagickDraw();

    $color = new \ImagickPixel('blue');
    $color->setcolorValue(\Imagick::COLOR_RED, 128);

    $draw->setstrokewidth(1.0);
    $draw->setStrokeColor($color);
    $draw->setFillColor($color);
    $draw->rectangle(200, 200, 300, 300);

    $image->newImage(500, 500, "SteelBlue2");
    $image->setImageFormat("png");
    $image->drawImage($draw);

    header("Content-Type: image/png");
    echo $image->getImageBlob();
}