public static Set<Coordinate> getCircle(
final Coordinate center, final int radius, final boolean fill) {
final Set<Coordinate> points = new LinkedHashSet<Coordinate>();
// Generate a list of all discrete points that fall inside the circle
if (fill) {
final int rad2 = radius * radius;
for (int r = center.getRow() - radius; r < center.getRow() + radius; r++) {
for (int c = center.getCol() - radius; c < center.getCol() + radius; c++) {
final int vDelta = (r - center.getRow());
final int hDelta = (c - center.getCol());
final int dist2 = vDelta * vDelta + hDelta * hDelta;
if (dist2 < rad2) {
points.add(new Coordinate(r, c));
}
}
}
}
final int centerRow = center.getRow();
final int centerCol = center.getCol();
// Bresenham's circle algorithm
int hDelta = 0;
int vDelta = radius;
int err = 3 - 2 * radius;
while (vDelta >= hDelta) {
points.add(new Coordinate(centerRow - hDelta, centerCol - vDelta));
points.add(new Coordinate(centerRow - vDelta, centerCol - hDelta));
points.add(new Coordinate(centerRow + vDelta, centerCol - hDelta));
points.add(new Coordinate(centerRow + hDelta, centerCol - vDelta));
points.add(new Coordinate(centerRow - hDelta, centerCol + vDelta));
points.add(new Coordinate(centerRow - vDelta, centerCol + hDelta));
points.add(new Coordinate(centerRow + vDelta, centerCol + hDelta));
points.add(new Coordinate(centerRow + hDelta, centerCol + vDelta));
if (err < 0) {
err += 4 * hDelta + 6;
hDelta++;
} else {
err += 4 * (hDelta - vDelta) + 10;
hDelta++;
vDelta--;
}
}
return points;
}
public static Set<Coordinate> getRectangle(
final Coordinate topLeft, final Coordinate bottomRight, final boolean fill) {
final Set<Coordinate> points = new LinkedHashSet<Coordinate>();
final Coordinate topRight = new Coordinate(topLeft.getRow(), bottomRight.getCol());
final Coordinate bottomLeft = new Coordinate(bottomRight.getRow(), topLeft.getCol());
points.addAll(getLine(topLeft, topRight));
points.addAll(getLine(topRight, bottomRight));
points.addAll(getLine(bottomRight, bottomLeft));
points.addAll(getLine(bottomLeft, topLeft));
if (fill) {
for (int r = topLeft.getRow() + 1; r < bottomRight.getRow(); r++) {
for (int c = topLeft.getCol() + 1; c < bottomRight.getCol(); c++) {
points.add(new Coordinate(r, c));
}
}
}
return points;
}
public static Set<Coordinate> getLine(final Coordinate pointA, final Coordinate pointB) {
final Set<Coordinate> points = new LinkedHashSet<Coordinate>();
final int deltaC = Math.abs(pointB.getCol() - pointA.getCol());
final int colStep = pointA.getCol() < pointB.getCol() ? 1 : -1;
final int deltaR = Math.abs(pointB.getRow() - pointA.getRow());
final int rowStep = pointA.getRow() < pointB.getRow() ? 1 : -1;
int err = (deltaC > deltaR ? deltaC : -deltaR) / 2;
int row = pointA.getRow();
int col = pointA.getCol();
points.add(pointA);
while (row != pointB.getRow() || col != pointB.getCol()) {
points.add(new Coordinate(row, col));
final int errorDelta = err;
if (errorDelta > -deltaC) {
err -= deltaR;
col += colStep;
}
if (errorDelta < deltaR) {
err += deltaC;
row += rowStep;
}
}
points.add(pointB);
return points;
}
