private function diffusion($image)
{
$pixels = array();
// Localize vars
$width = $image->getWidth();
$height = $image->getHeight();
// Loop using image1
$pixelIterator = $image->getCore()->getPixelIterator();
foreach ($pixelIterator as $y => $rows) {
/* Loop through pixel rows */
foreach ($rows as $x => $px) {
/* Loop through the pixels in the row (columns) */
/**
* @var $px \ImagickPixel */
$rgba = $px->getColor();
$gray = round($rgba['r'] * 0.3 + $rgba['g'] * 0.59 + $rgba['b'] * 0.11);
if (isset($pixels[$x][$y])) {
// Add errors to color if there are
$gray += $pixels[$x][$y];
}
if ($gray <= 127) {
// Determine if black or white. Also has the benefit of clipping excess val due to adding the error
$blackOrWhite = 0;
} else {
$blackOrWhite = 255;
}
$oldPixel = $gray;
$newPixel = $blackOrWhite;
// Current pixel
$px->setColor("rgb({$newPixel},{$newPixel},{$newPixel})");
$qError = $oldPixel - $newPixel;
// Quantization error
// Propagate error on neighbor pixels
if ($x + 1 < $width) {
$pixels[$x + 1][$y] = (isset($pixels[$x + 1][$y]) ? $pixels[$x + 1][$y] : 0) + $qError * (7 / 16);
}
if ($x - 1 > 0 and $y + 1 < $height) {
$pixels[$x - 1][$y + 1] = (isset($pixels[$x - 1][$y + 1]) ? $pixels[$x - 1][$y + 1] : 0) + $qError * (3 / 16);
}
if ($y + 1 < $height) {
$pixels[$x][$y + 1] = (isset($pixels[$x][$y + 1]) ? $pixels[$x][$y + 1] : 0) + $qError * (5 / 16);
}
if ($x + 1 < $width and $y + 1 < $height) {
$pixels[$x + 1][$y + 1] = (isset($pixels[$x + 1][$y + 1]) ? $pixels[$x + 1][$y + 1] : 0) + $qError * (1 / 16);
}
}
$pixelIterator->syncIterator();
/* Sync the iterator, this is important to do on each iteration */
}
$type = $image->getType();
$file = $image->getImageFile();
$image = $image->getCore();
return new Image($image, $file, $width, $height, $type);
// Create new image with updated core
}
