From 6df16d053ed9b50c495c1f86cebd3c166eb107de Mon Sep 17 00:00:00 2001
From: Seth Hillbrand <seth@kipro-pcb.com>
Date: Fri, 14 Jun 2024 17:26:21 -0700
Subject: [PATCH] Add specialization for unsigned scalar add/sub

Adding/subtracting an unsigned scalar to a signed vector should maintain
the same signed vector

Fixes https://gitlab.com/kicad/code/kicad/-/issues/18212
---
 libs/kimath/include/math/vector2d.h        | 13 +++++++++++++
 qa/tests/libs/kimath/math/test_vector2.cpp | 16 +++++++++++++---
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/libs/kimath/include/math/vector2d.h b/libs/kimath/include/math/vector2d.h
index 5c4cd71123..1b1ac85e6b 100644
--- a/libs/kimath/include/math/vector2d.h
+++ b/libs/kimath/include/math/vector2d.h
@@ -439,6 +439,13 @@ VECTOR2<std::common_type_t<T, U>> operator+( const VECTOR2<T>& aLHS, const U& aS
 }
 
 
+template <class T>
+VECTOR2<T> operator+( const VECTOR2<T>& aVector, std::unsigned_integral auto aScalar )
+{
+    return VECTOR2<T>( aVector.x + aScalar, aVector.y + aScalar );
+}
+
+
 template <class T, class U>
 VECTOR2<std::common_type_t<T, U>> operator-( const VECTOR2<T>& aLHS, const VECTOR2<U>& aRHS )
 {
@@ -452,6 +459,12 @@ VECTOR2<std::common_type_t<T, U>> operator-( const VECTOR2<T>& aLHS, const U& aS
     return VECTOR2<std::common_type_t<T, U>>( aLHS.x - aScalar, aLHS.y - aScalar );
 }
 
+template <class T>
+VECTOR2<T> operator-( const VECTOR2<T>& aVector, std::unsigned_integral auto aScalar )
+{
+    return VECTOR2<T>( aVector.x - aScalar, aVector.y - aScalar );
+}
+
 
 template <class T>
 VECTOR2<T> VECTOR2<T>::operator-()
diff --git a/qa/tests/libs/kimath/math/test_vector2.cpp b/qa/tests/libs/kimath/math/test_vector2.cpp
index 33825b819a..5ca2b0b79b 100644
--- a/qa/tests/libs/kimath/math/test_vector2.cpp
+++ b/qa/tests/libs/kimath/math/test_vector2.cpp
@@ -154,12 +154,22 @@ BOOST_AUTO_TEST_CASE( test_casting )
     BOOST_CHECK_EQUAL( vlong, VECTOR2L( -5, -4 ) );
     BOOST_CHECK_EQUAL( vfloat, VECTOR2<float>( -5.0f, -4.0f ) );
 
+    vint = vint - 1u;
+    vdouble = vdouble - 1u;
+    vlong = vlong - 1u;
+    vfloat = vfloat - 1u;
+
+    BOOST_CHECK_EQUAL( vint, VECTOR2I( -6, -5 ) );
+    BOOST_CHECK_EQUAL( vdouble, VECTOR2D( -6.0, -5.0 ) );
+    BOOST_CHECK_EQUAL( vlong, VECTOR2L( -6, -5 ) );
+    BOOST_CHECK_EQUAL( vfloat, VECTOR2<float>( -6.0f, -5.0f ) );
+
     auto add = vint + vdouble;
-    BOOST_CHECK_EQUAL( add, VECTOR2D( -10.0, -8.0 ) );
+    BOOST_CHECK_EQUAL( add, VECTOR2D( -12.0, -10.0 ) );
 
     auto sub = vint - 2 * vlong;
-    BOOST_CHECK_EQUAL( sub.x, 5 );
-    BOOST_CHECK_EQUAL( sub.y, 4 );
+    BOOST_CHECK_EQUAL( sub.x, 6 );
+    BOOST_CHECK_EQUAL( sub.y, 5 );
 
     vunsigned = VECTOR2<unsigned>( std::numeric_limits<unsigned>::max(), std::numeric_limits<unsigned>::max() );
     vint = VECTOR2I( vunsigned );