PCB_BASE_FRAME::FocusOnItem(): avoid extremely long calculation time for zones.

The algo used to calculate a focus point on a zone can be *extremely* time
consuming when using the filled areas in zone (can be matter of minutes and more).
So we use now only the zone outlines usually having not a lot of vertices.

pcbnew/pcb_base_frame.cpp

@@ -354,11 +354,31 @@ void PCB_BASE_FRAME::FocusOnItem( BOARD_ITEM* aItem, PCB_LAYER_ID aLayer )
         case PCB_FP_DIM_CENTER_T:
         case PCB_FP_DIM_RADIAL_T:
         case PCB_FP_DIM_ORTHOGONAL_T:
-        case PCB_ZONE_T:
             aItem->TransformShapeWithClearanceToPolygon( itemPoly, aLayer, 0, Millimeter2iu( 0.1 ),
                                                          ERROR_INSIDE );
             break;
 
+        case PCB_ZONE_T:
+        {
+            ZONE* zone = static_cast<ZONE*>( aItem );
+            #if 0
+            // Using the filled area shapes to find a Focus point can give good results, but
+            // unfortunately the calculations are highly time consuming, even for not very
+            // large areas (can be easily a few minutes for large areas).
+            // so we used only the zone outline that usually do not have too many vertices.
+            zone->TransformShapeWithClearanceToPolygon( itemPoly, aLayer, 0, Millimeter2iu( 0.1 ),
+                                                        ERROR_INSIDE );
+
+            if( itemPoly.IsEmpty() )
+                itemPoly = *zone->Outline();
+            #else
+            // much faster calculation time when using only the zone outlines
+            itemPoly = *zone->Outline();
+            #endif
+
+            break;
+        }
+
         default:
         {
             BOX2I item_bbox = aItem->GetBoundingBox();
@@ -396,7 +416,7 @@ void PCB_BASE_FRAME::FocusOnItem( BOARD_ITEM* aItem, PCB_LAYER_ID aLayer )
         while( !itemPoly.IsEmpty() )
         {
             focusPt = (wxPoint) itemPoly.BBox().Centre();
-            itemPoly.Deflate( step, 4 );
+            itemPoly.Deflate( step, 4, SHAPE_POLY_SET::CHAMFER_ACUTE_CORNERS );
         }
 
         FocusOnLocation( focusPt );

pcbnew/zone.cpp

@@ -1375,9 +1375,12 @@ void ZONE::TransformShapeWithClearanceToPolygon( SHAPE_POLY_SET& aCornerBuffer,
 
     aCornerBuffer = m_FilledPolysList.at( aLayer );
 
-    int numSegs = GetArcToSegmentCount( aClearance, aError, 360.0 );
-    aCornerBuffer.Inflate( aClearance, numSegs );
-    aCornerBuffer.Simplify( SHAPE_POLY_SET::PM_STRICTLY_SIMPLE );
+    // Rebuild filled areas only if clearance is not 0
+    if( aClearance )
+    {
+        int numSegs = GetArcToSegmentCount( aClearance, aError, 360.0 );
+        aCornerBuffer.InflateWithLinkedHoles( aClearance, numSegs, SHAPE_POLY_SET::PM_FAST );
+    }
 }