JansenFelipe\OMR\Scanners\ImagickScanner::rectangleArea PHP Method

    protected function rectangleArea(Point $a, Point $b, $tolerance)
    {
        $imagick = $this->getImagick();
        $width = $b->getX() - $a->getX();
        $height = $b->getY() - $a->getY();
        $pixels = $imagick->exportImagePixels($a->getX(), $a->getY(), $width, $height, "I", Imagick::PIXEL_CHAR);
        $counts = array_count_values($pixels);
        $blacks = 0;
        $whites = 0;
        foreach ($counts as $k => $qtd) {
            if ($k == -1) {
                $whites += $qtd;
            } else {
                $blacks += $qtd;
            }
        }
        $area = new Area(count($pixels), $whites, $blacks);
        //Add draw debug
        $this->draw->setStrokeOpacity(1);
        $this->draw->setFillOpacity(0);
        $this->draw->setStrokeWidth(2);
        $this->draw->setStrokeColor($area->percentBlack() >= $tolerance ? "#0000CC" : "#CC0000");
        $this->draw->rectangle($a->getX(), $a->getY(), $b->getX(), $b->getY());
        return $area;
    }