From 0d1038bcd4d4aa253a03068667b812b108fac1f0 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Mon, 25 May 2026 18:34:59 +0000
Subject: [PATCH] =?UTF-8?q?=E2=9A=A1=20Optimize=20redundant=20type=20casti?=
 =?UTF-8?q?ng=20in=20rasterizer=20loop?=
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Refactored `rasterize` to combine validation and processing into a single loop.
Ensured `class_id` is cast to an integer only once per geometry.
This optimization reduces redundant iterations and type casting, and improves support for single-use iterators.

Co-authored-by: tahamukhtar20 <91777330+tahamukhtar20@users.noreply.github.com>
---
 src/mapcv/rasterizer.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/mapcv/rasterizer.py b/src/mapcv/rasterizer.py
index cbe95c1..c61c05e 100644
--- a/src/mapcv/rasterizer.py
+++ b/src/mapcv/rasterizer.py
@@ -47,13 +47,13 @@ def rasterize(
     Background pixels are 0; polygons in later list positions overwrite
     earlier ones. Non-polygon geometries are silently skipped.
     """
-    if any(int(cid) <= 0 or int(cid) > 255 for _, cid in geometries):
-        raise ValueError("class_id must be in 1..=255 (0 is reserved for background)")
-
     height, width = out_shape
     polygons: List[Tuple[RingSet, int]] = []
     for geom, cid in geometries:
-        polygons.extend(_flatten(geom, int(cid)))
+        cid_int = int(cid)
+        if cid_int <= 0 or cid_int > 255:
+            raise ValueError("class_id must be in 1..=255 (0 is reserved for background)")
+        polygons.extend(_flatten(geom, cid_int))
 
     return cast(
         npt.NDArray[np.uint8],