feat: Add TopSky ECL drawer

Author: a3li

mapbuilder/handlers/jinja.py

@@ -15,6 +15,7 @@
 from mapbuilder.utils.geo import brg, fix
 from mapbuilder.utils.jinja_fragment_cache import FragmentCacheExtension
 from mapbuilder.utils.sidstar import render_sid
+from mapbuilder.utils.topsky import ecl
 
 
 class JinjaHandler:
@@ -44,6 +45,7 @@ def handle(self, item: Path) -> str:
             render_sectorlines=render_sectorlines,
             sector_sub=sector_sub,
             sector_and=sector_and,
+            ecl=ecl,
         )
         jinja_env.filters.update(
             geoms=geoms,

mapbuilder/utils/topsky.py

@@ -0,0 +1,26 @@
+def ecl(start: str, bearing: float, count: int, dist: float = 1, start_blank: bool = True):
+    """
+    Generates an extended center line (ECL) based on a starting point, bearing, number of segments,
+    distance between points, and whether the sequence begins with a blank segment.
+
+    Parameters:
+        start (str): The starting coordinate identifier.
+        bearing (float): The initial bearing in degrees, used to determine the direction of the line.
+        count (int): The total number of segments in the resultant line.
+        dist (float, optional): The distance between consecutive points in the line. Default is 1.
+        start_blank (bool, optional): Indicates whether to start the sequence with a blank segment. Default is True.
+
+    Returns:
+        str: A concatenated series of coordinate line segments formatted as strings.
+    """
+    lines = []
+    draw = not start_blank
+    for idx in range(0, count):
+        if draw and idx + 1 <= count:
+            lines.append(f"COORD_PBD:{start}:{bearing}:{dist * idx}")
+            lines.append(f"COORD_PBD:{start}:{bearing}:{dist * (idx + 1)}")
+            lines.append("COORDLINE")
+
+        draw = not draw
+
+    return "\n".join(lines)