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https://github.com/placeAtlas/atlas.git
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Added typing; added clarification
This commit is contained in:
Fabian Wunsch
parent
95c706f95a
commit
132798351d
1 changed files with 68 additions and 59 deletions
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@ -4,36 +4,49 @@
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"""
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from math import sqrt
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import time
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from typing import Tuple, List
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# Python3
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from queue import PriorityQueue
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from math import inf
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Point = Tuple[float, float]
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Polygon = List[Point]
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def _point_to_polygon_distance(x, y, polygon):
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inside = False
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min_distance_squared = inf
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SQRT2 = sqrt(2)
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previous = polygon[-1]
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def _point_to_polygon_distance(x: float, y: float, polygon: Polygon) -> (float, float):
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inside: bool = False
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min_distance_squared: float = inf
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max_distance_sqared: float = -inf
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previous: Point = polygon[-1]
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for current in polygon:
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if ((current[1] > y) != (previous[1] > y) and
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(x < (previous[0] - current[0]) * (y - current[1]) / (previous[1] - current[1]) + current[0])):
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inside = not inside
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min_distance_squared = min(min_distance_squared, _get_segment_distance_squared(x, y, current, previous))
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max_distance_sqared = max(max_distance_sqared, _get_max_point_distance(x, y, current))
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previous = current
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result = sqrt(min_distance_squared)
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result: float = sqrt(min_distance_squared)
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max_result: float = sqrt(max_distance_sqared)
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if not inside:
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return -result
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return result
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return -result, -max_result
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return result, max_result
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def _get_segment_distance_squared(px, py, point_a, point_b):
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x = point_a[0]
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y = point_a[1]
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dx = point_b[0] - x
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dy = point_b[1] - y
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def _get_max_point_distance(px: float, py: float, point: Point) -> float:
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return (px - point[0]) ** 2 + (py - point[1]) ** 2
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def _get_segment_distance_squared(px: float, py: float, point_a: Point, point_b: Point) -> float:
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x: float = point_a[0]
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y: float = point_a[1]
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dx: float = point_b[0] - x
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dy: float = point_b[1] - y
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if dx != 0 or dy != 0:
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t = ((px - x) * dx + (py - y) * dy) / (dx * dx + dy * dy)
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@ -53,12 +66,15 @@ def _get_segment_distance_squared(px, py, point_a, point_b):
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class Cell(object):
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def __init__(self, x, y, h, polygon):
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self.h = h
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self.y = y
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self.x = x
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self.d = _point_to_polygon_distance(x, y, polygon)
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self.max = self.d + self.h * sqrt(2)
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def __init__(self, x: float, y: float, h: float, polygon: Polygon):
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self.h: float = h
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self.y: float = y
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self.x: float = x
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min_dist, max_dist = _point_to_polygon_distance(x, y, polygon)
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self.min_dist: float = min_dist
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self.max_dist: float = max_dist
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self.max = self.min_dist + self.h * SQRT2
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self.weight = self.max
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def __lt__(self, other):
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return self.max < other.max
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@ -76,13 +92,13 @@ def __eq__(self, other):
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return self.max == other.max
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def _get_centroid_cell(polygon):
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area = 0
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x = 0
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y = 0
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previous = polygon[-1]
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def _get_centroid_cell(polygon: Polygon) -> Cell:
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area: float = 0
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x: float = 0
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y: float = 0
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previous: Point = polygon[-1]
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for current in polygon:
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f = current[0] * previous[1] - previous[0] * current[1]
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f: float = current[0] * previous[1] - previous[0] * current[1]
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x += (current[0] + previous[0]) * f
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y += (current[1] + previous[1]) * f
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area += f * 3
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@ -92,13 +108,13 @@ def _get_centroid_cell(polygon):
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return Cell(x / area, y / area, 0, polygon)
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def polylabel(polygon, precision=0.5, debug=False, with_distance=False):
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def polylabel(polygon: Polygon, precision: float=0.5, debug: bool=False):
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# find bounding box
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first_item = polygon[0]
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min_x = first_item[0]
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min_y = first_item[1]
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max_x = first_item[0]
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max_y = first_item[1]
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first_item: Point = polygon[0]
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min_x: float = first_item[0]
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min_y: float = first_item[1]
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max_x: float = first_item[0]
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max_y: float = first_item[1]
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for p in polygon:
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if p[0] < min_x:
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min_x = p[0]
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@ -109,64 +125,57 @@ def polylabel(polygon, precision=0.5, debug=False, with_distance=False):
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if p[1] > max_y:
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max_y = p[1]
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width = max_x - min_x
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height = max_y - min_y
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cell_size = min(width, height)
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h = cell_size / 2.0
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width: float = max_x - min_x
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height: float = max_y - min_y
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cell_size: float = min(width, height)
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h: float = cell_size / 2.0
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cell_queue = PriorityQueue()
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cell_queue: PriorityQueue[Tuple[float, int, Cell]] = PriorityQueue()
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if cell_size == 0:
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if with_distance:
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return [min_x, min_y], None
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else:
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return [min_x, min_y]
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return [(max_x - min_x) / 2, (max_y - min_y) / 2]
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# cover polygon with initial cells
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x = min_x
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x: float = min_x
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while x < max_x:
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y = min_y
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y: float = min_y
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while y < max_y:
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c = Cell(x + h, y + h, h, polygon)
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c: Cell = Cell(x + h, y + h, h, polygon)
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y += cell_size
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cell_queue.put((-c.max, time.time(), c))
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cell_queue.put((c.weight, time.time(), c))
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x += cell_size
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best_cell = _get_centroid_cell(polygon)
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best_cell: Cell = _get_centroid_cell(polygon)
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bbox_cell = Cell(min_x + width / 2, min_y + height / 2, 0, polygon)
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if bbox_cell.d > best_cell.d:
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bbox_cell: Cell = Cell(min_x + width / 2, min_y + height / 2, 0, polygon)
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if bbox_cell.min_dist > best_cell.min_dist:
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best_cell = bbox_cell
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num_of_probes = cell_queue.qsize()
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while not cell_queue.empty():
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_, __, cell = cell_queue.get()
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if cell.d > best_cell.d:
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if cell.min_dist > best_cell.min_dist:
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best_cell = cell
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if debug:
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print('found best {} after {} probes'.format(
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round(1e4 * cell.d) / 1e4, num_of_probes))
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print(f'found best {round(cell.min_dist, 4)} after {num_of_probes} probes')
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if cell.max - best_cell.d <= precision:
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if cell.max - best_cell.min_dist <= precision:
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continue
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h = cell.h / 2
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c = Cell(cell.x - h, cell.y - h, h, polygon)
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cell_queue.put((-c.max, time.time(), c))
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cell_queue.put((c.weight, time.time(), c))
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c = Cell(cell.x + h, cell.y - h, h, polygon)
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cell_queue.put((-c.max, time.time(), c))
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cell_queue.put((c.weight, time.time(), c))
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c = Cell(cell.x - h, cell.y + h, h, polygon)
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cell_queue.put((-c.max, time.time(), c))
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cell_queue.put((c.weight, time.time(), c))
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c = Cell(cell.x + h, cell.y + h, h, polygon)
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cell_queue.put((-c.max, time.time(), c))
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cell_queue.put((c.weight, time.time(), c))
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num_of_probes += 4
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if debug:
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print('num probes: {}'.format(num_of_probes))
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print('best distance: {}'.format(best_cell.d))
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if with_distance:
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return [best_cell.x, best_cell.y], best_cell.d
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else:
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print(f'num probes: {num_of_probes}')
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print(f'best distance: {best_cell.min_dist}')
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return [best_cell.x, best_cell.y]
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