From 112f089485430fdceb8a9752aa98e5aca3e14368 Mon Sep 17 00:00:00 2001
From: Roberto Fernandez Bautista <roberto.fer.bau@gmail.com>
Date: Fri, 2 Sep 2022 22:18:17 +0200
Subject: [PATCH] Fix TRANSFORM::MapAngles for other transformations than y=-y

Tested on transformation that results in: y=-y & x=-x

Fixes https://gitlab.com/kicad/code/kicad/-/issues/12345
---
 common/transform.cpp | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/common/transform.cpp b/common/transform.cpp
index ec8e650baa..ef5351a0dc 100644
--- a/common/transform.cpp
+++ b/common/transform.cpp
@@ -84,7 +84,7 @@ bool TRANSFORM::MapAngles( EDA_ANGLE* aAngle1, EDA_ANGLE* aAngle2 ) const
     VECTOR2D v;
     bool     swap = false;
 
-    EDA_ANGLE delta = ( *aAngle2 - *aAngle1 ).Normalize();
+    EDA_ANGLE delta = ( *aAngle2 - *aAngle1 ).Normalize180();
 
     x = aAngle1->Cos();
     y = aAngle1->Sin();
@@ -92,17 +92,16 @@ bool TRANSFORM::MapAngles( EDA_ANGLE* aAngle1, EDA_ANGLE* aAngle2 ) const
     *aAngle1 = EDA_ANGLE( v );
     aAngle1->Normalize180();
 
-    // Transform the relative difference between the two angles
-    x = delta.Cos();
-    y = delta.Sin();
+    x = aAngle2->Cos();
+    y = aAngle2->Sin();
     v = VECTOR2D( x * x1 + y * y1, x * x2 + y * y2 );
-    EDA_ANGLE deltaTransformed( v );
+    *aAngle2 = EDA_ANGLE( v );
+    aAngle2->Normalize180();
 
-    // Calculate the second angle using the first one as an anchor
-    *aAngle2 = *aAngle1 + deltaTransformed;
+    EDA_ANGLE deltaTransformed = ( *aAngle2 - *aAngle1 ).Normalize180();
 
-    if( sign( deltaTransformed.Normalize180().AsDegrees() )
-        != sign( delta.Normalize180().AsDegrees() ) )
+    if( sign( deltaTransformed.AsDegrees() )
+        != sign( delta.AsDegrees() ) )
     {
         std::swap( *aAngle1, *aAngle2 );
         swap = true;