Package pygeodesy :: Module clipy
[frames] | no frames]

Module clipy

Clip a path or polygon.

Clip a path or polygon of LatLon points against a rectangular box or a (convex) clip region.


Version: 21.10.23

Classes
  ClipError
Clip box or clip region issue.
  ClipCS4Tuple
4-Tuple (start, end, i, j) for each edge of a clipped path with the start and end points (LatLon) of the portion of the edge inside or on the clip box and the indices i and j (int) of the edge start and end points in the original path.
  ClipLB6Tuple
6-Tuple (start, end, i, fi, fj, j) for each edge of the clipped path with the start and end points (LatLon) of the portion of the edge inside or on the clip box, indices i and j (both int) of the original path edge start and end points and fractional indices fi and fj (both FIx) of the start and end points along the edge of the original path.
  ClipSH3Tuple
3-Tuple (start, end, original) for each edge of a clipped polygon, the start and end points (LatLon) of the portion of the edge inside or on the clip region and original indicates whether the edge is part of the original polygon or part of the clip region (bool).
Functions
 
clipCS4(points, lowerleft, upperright, closed=False, inull=False)
Clip a path against a rectangular clip box using the Cohen-Sutherland algorithm.
 
clipLB6(points, lowerleft, upperright, closed=False, inull=False)
Clip a path against a rectangular clip box using the Liang-Barsky algorithm.
 
clipSH(points, corners, closed=False, inull=False)
Clip a polygon against a clip region or box using the Sutherland-Hodgman algorithm.
 
clipSH3(points, corners, closed=False, inull=False)
Clip a polygon against a clip region or box using the Sutherland-Hodgman algorithm.
Variables
  __all__ = _ALL_LAZY.clipy
Function Details

clipCS4 (points, lowerleft, upperright, closed=False, inull=False)

 

Clip a path against a rectangular clip box using the Cohen-Sutherland algorithm.

Arguments:
  • points - The points (LatLon[]).
  • lowerleft - Bottom-left corner of the clip box (LatLon).
  • upperright - Top-right corner of the clip box (LatLon).
  • closed - Optionally, close the path (bool).
  • inull - Optionally, retain null edges if inside (bool).
Returns:
Yield a ClipCS4Tuple(start, end, i, j) for each edge of the clipped path.
Raises:
  • ClipError - The lowerleft and upperright corners specify an invalid clip box.
  • PointsError - Insufficient number of points.

clipLB6 (points, lowerleft, upperright, closed=False, inull=False)

 

Clip a path against a rectangular clip box using the Liang-Barsky algorithm.

Arguments:
  • points - The points (LatLon[]).
  • lowerleft - Bottom-left corner of the clip box (LatLon).
  • upperright - Top-right corner of the clip box (LatLon).
  • closed - Optionally, close the path (bool).
  • inull - Optionally, retain null edges if inside (bool).
Returns:
Yield a ClipLB6Tuple(start, end, i, fi, fj, j) for each edge of the clipped path.
Raises:
  • ClipError - The lowerleft and upperright corners specify an invalid clip box.
  • PointsError - Insufficient number of points.

clipSH (points, corners, closed=False, inull=False)

 

Clip a polygon against a clip region or box using the Sutherland-Hodgman algorithm.

Arguments:
  • points - The polygon points (LatLon[]).
  • corners - Three or more points defining a convex clip region (LatLon[]) or two points to specify a rectangular clip box.
  • closed - Close the clipped points (bool).
  • inull - Optionally, include null edges (bool).
Returns:
Yield the clipped points (LatLon[]).
Raises:
  • ClipError - The corners specify a polar, zero-area, non-convex or otherwise invalid clip box or region.
  • PointsError - Insufficient number of points.

clipSH3 (points, corners, closed=False, inull=False)

 

Clip a polygon against a clip region or box using the Sutherland-Hodgman algorithm.

Arguments:
  • points - The polygon points (LatLon[]).
  • corners - Three or more points defining a convex clip region (LatLon[]) or two points to specify a rectangular clip box.
  • closed - Close the clipped points (bool).
  • inull - Optionally, include null edges (bool).
Returns:
Yield a ClipSH3Tuple(start, end, original) for each edge of the clipped polygon.
Raises:
  • ClipError - The corners specify a polar, zero-area, non-convex or otherwise invalid clip box or region.
  • PointsError - Insufficient number of points.