From 0530c365ca569435c396481605c05392829708ac Mon Sep 17 00:00:00 2001
From: jaseg <git@jaseg.de>
Date: Wed, 2 Jun 2021 11:57:00 +0200
Subject: Add polygon area function & tests. These tests catch a single-px bug.

---
 svg-flatten/src/nopencv.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'svg-flatten/src/nopencv.cpp')

diff --git a/svg-flatten/src/nopencv.cpp b/svg-flatten/src/nopencv.cpp
index 18d3f20..c222734 100644
--- a/svg-flatten/src/nopencv.cpp
+++ b/svg-flatten/src/nopencv.cpp
@@ -427,3 +427,14 @@ bool gerbolyze::nopencv::Image32::stb_to_internal(uint8_t *data) {
     stbi_image_free(data);
     return true;
 }
+
+double gerbolyze::nopencv::polygon_area(Polygon_i &poly) {
+    double acc = 0;
+    size_t prev = poly.size() - 1;
+    for (size_t cur=0; cur<poly.size(); cur++) {
+        acc += (poly[prev][0] + poly[cur][0]) * (poly[prev][1] - poly[cur][1]);
+        prev = cur;
+    }
+    return acc / 2;
+}
+
-- 
cgit