From ba97d2928ec3d15f2baacd41e3e8455b81b5932f Mon Sep 17 00:00:00 2001
From: Omar Rizwan <omar@omar.website>
Date: Sun, 9 Jul 2023 16:26:28 -0400
Subject: Implement `region rotate` helper

---
 virtual-programs/regions.folk | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'virtual-programs')

diff --git a/virtual-programs/regions.folk b/virtual-programs/regions.folk
index 10684a59..b1cf45a0 100644
--- a/virtual-programs/regions.folk
+++ b/virtual-programs/regions.folk
@@ -127,6 +127,17 @@ namespace eval ::region {
         vec2 scale $vecsum 0.25
     }
 
+    proc rotate {r angle} {
+        set theta [angle $r]
+        set c [centroid $r]
+        mapVertices v $r {
+            set v [vec2 sub $v $c]
+            set v [vec2 rotate $v $angle]
+            set v [vec2 add $v $c]
+            set v
+        }
+    }
+
     # Scales about the center of the region, along the x and y axes of
     # the space of the region (not the global x and y).
     proc scale {r args} {
-- 
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