From 8ed7394431bb74d96f14ea416069f6f468ac2483 Mon Sep 17 00:00:00 2001
From: "R. Timothy Edwards" <tim@opencircuitdesign.com>
Date: Fri, 1 Aug 2025 10:47:01 -0400
Subject: [PATCH] Corrected some basic paint code related to drawing over top
 non- Manhattan tiles.  After splitting a non-Manhattan tile crossing a search
 area to paint, the routine was automatically merging tiles to the right. 
 This is incorrect for tiles inside the search area, as it can cause the
 search algorithm to miss unvisited tiles whose origins are to the left of the
 split tile, resulting in part of the area not getting painted.

---
 VERSION            |  2 +-
 database/DBpaint.c | 68 ++++++++++++++++++++++++++++++++++------------
 2 files changed, 52 insertions(+), 18 deletions(-)

diff --git a/VERSION b/VERSION
index 798215ef..9aebba3a 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-8.3.534
+8.3.535
diff --git a/database/DBpaint.c b/database/DBpaint.c
index 8493c7a6..0f90c1c6 100644
--- a/database/DBpaint.c
+++ b/database/DBpaint.c
@@ -59,6 +59,8 @@ Tile *TiNMMergeRight();
 Tile *TiNMMergeLeft();
 
 #ifdef	PAINTDEBUG
+void dbPaintShowTile(Tile *tile, PaintUndoInfo *undo, char *str);
+
 int dbPaintDebug = 0;
 #endif	/* PAINTDEBUG */
 
@@ -311,6 +313,11 @@ enumerate:
 	 * Set up the directions in which we will have to
 	 * merge initially.  Clipping can cause some of these
 	 * to be turned off.
+	 *
+	 * The search runs from left to right, top to bottom.
+	 * Therefore always merge left and up, but never right
+	 * and down, unless at or beyond the each of the search
+	 * area.
 	 */
 	mergeFlags = MRG_TOP | MRG_LEFT;
 	if (RIGHT(tile) >= area->r_xtop) mergeFlags |= MRG_RIGHT;
@@ -340,6 +347,7 @@ enumerate:
 	     * Merging is only necessary if we clip to the left or to
 	     * the right, and then only to the top or the bottom.
 	     * We do the merge in-line for efficiency.
+	     * Clipping of split tiles is more complicated.
 	     */
 
 	    /* Clip up */
@@ -354,13 +362,17 @@ enumerate:
 			newType = (method == (unsigned char)PAINT_XOR) ?
 				 *resultTbl : resultTbl[oldType];
 
-			tile = TiNMMergeLeft(tile, plane);
-			TiNMMergeRight(TR(newtile), plane);
+			if (mergeFlags & MRG_LEFT)
+			    tile = TiNMMergeLeft(tile, plane);
+			if ((mergeFlags & MRG_RIGHT) || SplitDirection(newtile) == 1)
+			    TiNMMergeRight(TR(newtile), plane);
 		    }
 		    else
 		    {
-			TiNMMergeLeft(newtile, plane);
-			TiNMMergeRight(TR(tile), plane);
+			if (mergeFlags & MRG_LEFT)
+			    TiNMMergeLeft(newtile, plane);
+			if ((mergeFlags & MRG_RIGHT) || SplitDirection(tile) == 1)
+			    TiNMMergeRight(TR(tile), plane);
 		    }
 		}
 		else
@@ -389,13 +401,17 @@ enumerate:
 			newType = (method == (unsigned char)PAINT_XOR) ?
 				 *resultTbl : resultTbl[oldType];
 
-			tile = TiNMMergeLeft(tile, plane);
-			TiNMMergeRight(TR(newtile), plane);
+			if (mergeFlags & MRG_LEFT)
+			    tile = TiNMMergeLeft(tile, plane);
+			if ((mergeFlags & MRG_RIGHT) || SplitDirection(newtile) == 0)
+			    TiNMMergeRight(TR(newtile), plane);
 		    }
 		    else
 		    {
-			TiNMMergeLeft(newtile, plane);
-			TiNMMergeRight(TR(tile), plane);
+			if (mergeFlags & MRG_LEFT)
+			    TiNMMergeLeft(newtile, plane);
+			if ((mergeFlags & MRG_RIGHT) || SplitDirection(tile) == 0)
+			    TiNMMergeRight(TR(tile), plane);
 		    }
 		}
 		else
@@ -424,13 +440,17 @@ enumerate:
 			newType = (method == (unsigned char)PAINT_XOR) ?
 				 *resultTbl : resultTbl[oldType];
 
-			tile = TiNMMergeLeft(tile, plane);
-			TiNMMergeRight(LB(newtile), plane);
+			if (mergeFlags & MRG_LEFT)
+			    tile = TiNMMergeLeft(tile, plane);
+			if (mergeFlags & MRG_RIGHT)
+			    TiNMMergeRight(LB(newtile), plane);
 		    }
 		    else
 		    {
-			TiNMMergeRight(newtile, plane);
-			TiNMMergeLeft(LB(tile), plane);
+			if (mergeFlags & MRG_LEFT)
+			    TiNMMergeRight(newtile, plane);
+			if (mergeFlags & MRG_RIGHT)
+			    TiNMMergeLeft(LB(tile), plane);
 		    }
 		}
 		else
@@ -467,13 +487,17 @@ enumerate:
 			newType = (method == (unsigned char)PAINT_XOR) ?
 				 *resultTbl : resultTbl[oldType];
 
-			// tile = TiNMMergeRight(tile, plane);
-			TiNMMergeLeft(LB(newtile), plane);
+			if (mergeFlags & MRG_RIGHT)
+			    tile = TiNMMergeRight(tile, plane);  // was commented out?
+			if (mergeFlags & MRG_LEFT)
+			    TiNMMergeLeft(LB(newtile), plane);
 		    }
 		    else
 		    {
-			TiNMMergeLeft(newtile, plane);
-			// TiNMMergeRight(LB(tile), plane);
+			if (mergeFlags & MRG_LEFT)
+			    TiNMMergeLeft(newtile, plane);
+			if (mergeFlags & MRG_RIGHT)
+			    TiNMMergeRight(LB(tile), plane);	// was commented out?
 		    }
 		}
 		else
@@ -3018,7 +3042,7 @@ dbPaintMergeVert(tile, newType, plane, mergeFlags, undo)
  * ----------------------------------------------------------------------------
  */
 
-#include "styles.h"
+#include "utils/styles.h"
 
 void
 dbPaintShowTile(tile, undo, str)
@@ -3041,6 +3065,16 @@ dbPaintShowTile(tile, undo, str)
     TxPrintf("%s --more--", str); fflush(stdout);
     (void) TxGetLine(answer, sizeof answer);
     DBWFeedbackClear(NULL);
+
+    /* To debug tile operations that happen away from the active layout
+     * window, it may be advantageous to replace the display code above
+     * with the print statement below.
+     */
+    /*
+    TxPrintf("Debug %s: Tile (%d %d) to (%d %d) type %d\n",
+		str, LEFT(tile), BOTTOM(tile), RIGHT(tile), TOP(tile),
+		TiGetBody(tile));
+    */
 }
 #endif	/* PAINTDEBUG */