public function crawl($x, $y)
{
// Set the starting position to crawl;
$this->x = $x;
$this->y = $y;
$turns = 0;
$outline = new CrawlerOutline($this->matrix->pixel($x, $y));
do {
switch (true) {
// L1
case $this->look(1):
$turns = 0;
$this->walk()->turnLeft()->walk();
$outline->push($this->matrix->pixel($this->x, $this->y));
break;
// L2
// L2
case $this->look(2):
$turns = 0;
$this->walk();
$outline->push($this->matrix->pixel($this->x, $this->y));
break;
// L3
// L3
case $this->look(3):
$turns = 0;
$this->turnRight()->walk()->turnLeft()->walk();
$outline->push($this->matrix->pixel($this->x, $this->y));
break;
// Turn
// Turn
default:
$turns++;
$this->turnRight();
}
// Complete condition
if ($turns == 4 || $outline->closed()) {
break;
}
} while (true);
return $outline;
}
public function sliceByOutline(CrawlerOutline $outline)
{
$target = imagecreatetruecolor($outline->boundary->width(), $outline->boundary->height());
imagefill($target, 0, 0, 0xffffff);
$topLeft = $outline->boundary->topLeft();
$bottomRight = $outline->boundary->bottomRight();
for ($x = $topLeft->x(); $x <= $bottomRight->x(); $x++) {
for ($y = $topLeft->y(); $y <= $bottomRight->y(); $y++) {
if ($outline->contains(new Point($x, $y))) {
imagesetpixel($target, $x - $topLeft->x(), $y - $topLeft->y(), imagecolorat($this->img, $x, $y));
}
}
}
return self::fromResource($target);
}
