php imagick像素迭代器与下一个和上一个像素相比

$imagick = new \Imagick(realpath($imagePath));
$imageIterator = $imagick->getPixelIterator();

foreach ($imageIterator as $row => $pixels) { /* Loop through pixel rows */
    foreach ($pixels as $column => $pixel) { 
         if ($column % 2) {

How do I compare this pixel to the one above and below and the one to the left and right, I will be using isSimilar which I already understand

getNextIteratorRow/getPreviousIteratorRow maybe? Is their something similar for pixels?

}
    }
    $imageIterator->syncIterator(); 
}

That is the question how do I navigate from the current pixel to the one above, below, left and right.

Assistance much appreciated.

This is one of those problems that is probably best solved by just writing some code.

function processPixel($pixeLeft, $pixelMiddle, $pixelRight, $pixelAbove, $rowBelow)
{
    //Whatever it is you're doing.
}

function processRow($rowAbove, $rowMiddle, $rowBelow)
{
    for ($x = 0; $x < count($pixels); $x++) {
        $pixelAbove = null;
        $pixelBelow = null;
        $pixeLeft = null;
        $pixelRight = null;
        $pixelMiddle = $pixels[0];

        if (($x - 1) >= 0) {
            $pixelLeft = $pixels[$x - 1];
        }

        if (($x + 1) < count($pixels)) {
            $pixelRight = $pixels[$x + 1];
        }

        if ($rowAbove != null) {
            $pixelAbove = $rowAbove[$x];
        }
        if ($rowBelow != null) {
            $rowBelow = $rowBelow[$x];
        }

        processPixel($pixeLeft, $pixelMiddle, $pixelRight, $pixelAbove, $rowBelow)
    }
}

function processImageIterator($imageIterator)
{
    $rowAbove = null;
    $rowMiddle = null;
    $rowBelow = null;

    foreach ($imageIterator as $rowPixels) {

        $rowBelow = $rowPixels;

        foreach ($imageIterator as $rowPixels) {
            processRow($rowAbove, $rowMiddle, $rowBelow);
        }

        $rowAbove = $rowMiddle;
        $rowMiddle = $rowBelow;
    }

    // Finish last row with middle on the last row
    processRow($rowAbove, $rowMiddle, null);

    //Finish row of pixel below last row. This may not be necessary
    //depending on your algorithm,
    $rowAbove = $rowMiddle;
    processRow($rowAbove, null, null);
}

Just to note, this will be highly non-performant, aka slow as heck. It may (but not guaranteed) be faster to implement whatever it is you're trying to do as an FX operator. Example here and full documentation here.