Corrected two errors with the wiring tool: (1) Ignore

"angles"-type width rules when calculating the default metal
width DRC rule (this width when present will always be
larger than the minimum metal width), and (2) If an exiting
wire is larger than the contact size, then set the contact
size such that the contact PLUS the surrounding metal is the
width of the exiting wire.  The existing code sets the
contact size itself to the width of the exiting wire, such
that when surrounding material is added, the contact is
larger than it needs to be.  The fix to (1) will also fix
other places where the default DRC width rule is computed,
which includes LEF and DEF handling and computing rendered
text sizes when reading GDS.

Author: RTimothyEdwards

drc/DRCtech.c

@@ -4237,8 +4237,8 @@ DRCGetDefaultLayerWidth(ttype)
 	/* Skip area rule */
 	if (cptr->drcc_flags & DRC_AREA) continue;
 
-	/* FORWARD rules only, and no MAXWIDTH */
-	if ((cptr->drcc_flags & (DRC_REVERSE | DRC_MAXWIDTH)) == 0)
+	/* FORWARD rules only, and no MAXWIDTH or SPLITTILE */
+	if ((cptr->drcc_flags & (DRC_REVERSE | DRC_MAXWIDTH | DRC_SPLITTILE)) == 0)
 	{
 	    set = &cptr->drcc_mask;
 	    if (TTMaskHasType(set, ttype) && TTMaskEqual(set, &cptr->drcc_corner))

wiring/wireOps.c

@@ -826,7 +826,23 @@ WireAddContact(newType, newWidth)
 
     gotContact:
     totalSize = conSize + 2 * oldOverlap;
-    if (totalSize < WireWidth) totalSize = WireWidth;
+
+    /* If the contact size + overlap is less than the wire width,
+     * then make the contact size equal to the wire width - the
+     * overlap so that the full contact area isn't larger than
+     * the exiting wire width.
+     */
+    if (updown == WIRING_CONTACT_UP)
+    {
+	if (totalSize < (WireWidth - 2 * conSurround2))
+	    totalSize = WireWidth - 2 * conSurround2;
+    }
+    else
+    {
+	if (totalSize < (WireWidth - 2 * conSurround1))
+	    totalSize = WireWidth - 2 * conSurround1;
+    }
+
     contactArea = oldLeg;
     if ((contactArea.r_xtop - contactArea.r_xbot) < totalSize)
     {