Imagick::posterizeImage
  (PECL imagick 2, PECL imagick 3)
Imagick::posterizeImage — Reduces the image to a limited number of color level
  
 
  Description
  
   public Imagick::posterizeImage(
int $levels, 
bool $dither): 
bool 
  
  
 
 
  Return Values
  
   Returns true on success.
  
  
 
  Examples
  
    
      Example #1  Imagick::posterizeImage()
      
      <?php
function posterizeImage($imagePath, $posterizeType, $numberLevels) {
    $imagick = new \Imagick(realpath($imagePath));
    $imagick->posterizeImage($numberLevels, $posterizeType);
    $imagick->setImageFormat('png');
    header("Content-Type: image/png");
    echo $imagick->getImageBlob();
}
posterizeImage($imagePath, \Imagick::DITHERMETHOD_RIEMERSMA, 8);
?>