From ba9e9a2368aa3097e138d645fd3862736872368e Mon Sep 17 00:00:00 2001
From: Seth Hillbrand <seth@kipro-pcb.com>
Date: Sun, 24 Aug 2025 14:24:51 -0700
Subject: [PATCH] Be more explicit in the board outline errors

Show the two items that are closest to the gap and put the marker
directly in the gap center.  Then report the space between them to allow
the designer more information about what to look for
---
 pcbnew/drc/drc_test_provider_misc.cpp | 100 +++++++++++++++++++++++++-
 1 file changed, 98 insertions(+), 2 deletions(-)

diff --git a/pcbnew/drc/drc_test_provider_misc.cpp b/pcbnew/drc/drc_test_provider_misc.cpp
index 9d90d1c7cd..81e76cb70a 100644
--- a/pcbnew/drc/drc_test_provider_misc.cpp
+++ b/pcbnew/drc/drc_test_provider_misc.cpp
@@ -27,12 +27,16 @@
 #include <drc/drc_rule.h>
 #include <drc/drc_rule_condition.h>
 #include <drc/drc_test_provider.h>
+#include <collectors.h>
+#include <pcb_shape.h>
 #include <pad.h>
 #include <pcb_track.h>
 
 #include <drawing_sheet/ds_draw_item.h>
 #include <drawing_sheet/ds_proxy_view_item.h>
 
+#include <limits>
+
 /*
     Miscellaneous tests:
 
@@ -44,6 +48,64 @@
     - DRCE_GENERIC_ERROR                      ///< user-defined errors
 */
 
+static void findClosestOutlineGap( BOARD* aBoard, PCB_SHAPE*& aItemA, PCB_SHAPE*& aItemB,
+                                   VECTOR2I& aMidpoint, int& aDistance )
+{
+    PCB_TYPE_COLLECTOR items;
+    items.Collect( aBoard, { PCB_SHAPE_T } );
+
+    std::vector<PCB_SHAPE*> shapes;
+
+    for( int ii = 0; ii < items.GetCount(); ++ii )
+    {
+        PCB_SHAPE* shape = static_cast<PCB_SHAPE*>( items[ii] );
+
+        if( shape->GetLayer() == Edge_Cuts )
+            shapes.push_back( shape );
+    }
+
+    int       best = std::numeric_limits<int>::max();
+    VECTOR2I  bestA;
+    VECTOR2I  bestB;
+
+    for( size_t ii = 0; ii < shapes.size(); ++ii )
+    {
+        std::shared_ptr<SHAPE> shapeA = shapes[ii]->GetEffectiveShape();
+
+        for( size_t jj = ii + 1; jj < shapes.size(); ++jj )
+        {
+            std::shared_ptr<SHAPE> shapeB = shapes[jj]->GetEffectiveShape();
+            VECTOR2I            ptA;
+            VECTOR2I            ptB;
+
+            if( shapeA && shapeB && shapeA->NearestPoints( shapeB.get(), ptA, ptB ) )
+            {
+                int dist = ( ptA - ptB ).EuclideanNorm();
+
+                if( dist < best )
+                {
+                    best = dist;
+                    bestA = ptA;
+                    bestB = ptB;
+                    aItemA = shapes[ii];
+                    aItemB = shapes[jj];
+                }
+            }
+        }
+    }
+
+    if( aItemA && aItemB )
+    {
+        aDistance = best;
+        aMidpoint = ( bestA + bestB ) / 2;
+    }
+    else
+    {
+        aDistance = 0;
+        aMidpoint = VECTOR2I();
+    }
+}
+
 class DRC_TEST_PROVIDER_MISC : public DRC_TEST_PROVIDER
 {
 public:
@@ -85,12 +147,46 @@ void DRC_TEST_PROVIDER_MISC::testOutline()
                 if( !itemA )        // If we only have a single item, make sure it's A
                     std::swap( itemA, itemB );
 
+                VECTOR2I markerPos = pt;
+                int      gap = 0;
+
+                if( itemA && itemB )
+                {
+                    std::shared_ptr<SHAPE> shapeA = itemA->GetEffectiveShape();
+                    std::shared_ptr<SHAPE> shapeB = itemB->GetEffectiveShape();
+                    VECTOR2I            ptA;
+                    VECTOR2I            ptB;
+
+                    if( shapeA && shapeB && shapeA->NearestPoints( shapeB.get(), ptA, ptB ) )
+                    {
+                        gap = ( ptA - ptB ).EuclideanNorm();
+                        markerPos = ( ptA + ptB ) / 2;
+                    }
+                }
+                else
+                {
+                    PCB_SHAPE* shapeA = nullptr;
+                    PCB_SHAPE* shapeB = nullptr;
+
+                    findClosestOutlineGap( m_board, shapeA, shapeB, markerPos, gap );
+
+                    itemA = shapeA;
+                    itemB = shapeB;
+                }
+
                 std::shared_ptr<DRC_ITEM> drcItem = DRC_ITEM::Create( DRCE_INVALID_OUTLINE );
 
-                drcItem->SetErrorMessage( drcItem->GetErrorText() + wxS( " " ) + msg );
+                wxString msg2;
+
+                if( itemA && itemB )
+                    msg2.Printf( _( "%s (gap %s)" ), msg, MessageTextFromValue( gap ) );
+                else
+                    msg2 = msg;
+
+                drcItem->SetErrorMessage( drcItem->GetErrorText() + wxS( " " ) + msg2 );
                 drcItem->SetItems( itemA, itemB );
 
-                reportViolation( drcItem, pt, Edge_Cuts );
+                reportViolation( drcItem, markerPos, Edge_Cuts );
             };
 
     // Test for very small graphic items (a few nm size) that can create issues