pcbnew: Implement consistent graphical snapping

This creates a standard snapping framework in the GRID_HELPER class that
allows snapping to items on the same layer as the object being
created/moved as well as consistent toggling of this using the Shift key
modifier.

Fixes: lp:806260
* https://bugs.launchpad.net/kicad/+bug/806260

Fixes: lp:1604616
* https://bugs.launchpad.net/kicad/+bug/1604616

pcbnew/tools/drawing_tool.cpp

@@ -975,6 +975,7 @@ bool DRAWING_TOOL::drawSegment( int aShape, DRAWSEGMENT*& aGraphic,
     assert( aShape == S_SEGMENT || aShape == S_CIRCLE );
 
     DRAWSEGMENT line45;
+    GRID_HELPER grid( m_frame );
 
     m_frame->SetActiveLayer( getDrawingLayer() );
 
@@ -998,9 +999,11 @@ bool DRAWING_TOOL::drawSegment( int aShape, DRAWSEGMENT*& aGraphic,
         // Init the new item attributes
         aGraphic->SetShape( (STROKE_T) aShape );
         aGraphic->SetWidth( m_lineWidth );
-        aGraphic->SetStart( wxPoint( aStartingPoint->x, aStartingPoint->y ) );
-        aGraphic->SetEnd( wxPoint( cursorPos.x, cursorPos.y ) );
         aGraphic->SetLayer( getDrawingLayer() );
+        aGraphic->SetStart( wxPoint( aStartingPoint->x, aStartingPoint->y ) );
+
+        cursorPos = grid.BestSnapAnchor( cursorPos, aGraphic );
+        aGraphic->SetEnd( wxPoint( cursorPos.x, cursorPos.y ) );
 
         if( aShape == S_SEGMENT )
             line45 = *aGraphic; // used only for direction 45 mode with lines
@@ -1018,7 +1021,9 @@ bool DRAWING_TOOL::drawSegment( int aShape, DRAWSEGMENT*& aGraphic,
     // Main loop: keep receiving events
     while( OPT_TOOL_EVENT evt = Wait() )
     {
-        cursorPos = m_controls->GetCursorPosition();
+        grid.SetSnap( !evt->Modifier( MD_SHIFT ) );
+
+        cursorPos = grid.BestSnapAnchor( evt->Position(), aGraphic );
 
         // 45 degree angle constraint enabled with an option and toggled with Ctrl
         const bool limit45 = ( frame()->Settings().m_use45DegreeGraphicSegments != !!( evt->Modifier( MD_CTRL ) ) );
@@ -1030,7 +1035,7 @@ bool DRAWING_TOOL::drawSegment( int aShape, DRAWSEGMENT*& aGraphic,
             if( direction45 )
             {
                 preview.Add( &line45 );
-                make45DegLine( aGraphic, &line45 );
+                make45DegLine( aGraphic, &line45, cursorPos );
             }
             else
             {
@@ -1121,7 +1126,7 @@ bool DRAWING_TOOL::drawSegment( int aShape, DRAWSEGMENT*& aGraphic,
         {
             // 45 degree lines
             if( direction45 && aShape == S_SEGMENT )
-                make45DegLine( aGraphic, &line45 );
+                make45DegLine( aGraphic, &line45, cursorPos );
             else
                 aGraphic->SetEnd( wxPoint( cursorPos.x, cursorPos.y ) );
 
@@ -1198,6 +1203,7 @@ bool DRAWING_TOOL::drawArc( DRAWSEGMENT*& aGraphic )
     SELECTION preview;
     m_view->Add( &preview );
     m_view->Add( &arcAsst );
+    GRID_HELPER grid( m_frame );
 
     m_controls->ShowCursor( true );
     m_controls->SetSnapping( true );
@@ -1209,7 +1215,11 @@ bool DRAWING_TOOL::drawArc( DRAWSEGMENT*& aGraphic )
     // Main loop: keep receiving events
     while( OPT_TOOL_EVENT evt = Wait() )
     {
-        const VECTOR2I cursorPos = m_controls->GetCursorPosition();
+        PCB_LAYER_ID layer = getDrawingLayer();
+        aGraphic->SetLayer( layer );
+
+        grid.SetSnap( !evt->Modifier( MD_SHIFT ) );
+        const VECTOR2I cursorPos = grid.BestSnapAnchor( evt->Position(), aGraphic );
 
         if( evt->IsClick( BUT_LEFT ) )
         {
@@ -1218,13 +1228,10 @@ bool DRAWING_TOOL::drawArc( DRAWSEGMENT*& aGraphic )
                 m_controls->SetAutoPan( true );
                 m_controls->CaptureCursor( true );
 
-                PCB_LAYER_ID layer = getDrawingLayer();
-
                 // Init the new item attributes
                 // (non-geometric, those are handled by the manager)
                 aGraphic->SetShape( S_ARC );
                 aGraphic->SetWidth( m_lineWidth );
-                aGraphic->SetLayer( layer );
 
                 preview.Add( aGraphic );
                 firstPoint = true;
@@ -1342,13 +1349,16 @@ void DRAWING_TOOL::runPolygonEventLoop( POLYGON_GEOM_MANAGER& polyGeomMgr )
     auto&   controls    = *getViewControls();
     bool    started     = false;
 
+    GRID_HELPER grid( m_frame );
     STATUS_TEXT_POPUP status( m_frame );
     status.SetTextColor( wxColour( 255, 0, 0 ) );
     status.SetText( _( "Self-intersecting polygons are not allowed" ) );
 
     while( OPT_TOOL_EVENT evt = Wait() )
     {
-        VECTOR2I cursorPos = controls.GetCursorPosition();
+        LSET layers( m_frame->GetActiveLayer() );
+        grid.SetSnap( !evt->Modifier( MD_SHIFT ) );
+        VECTOR2I cursorPos = grid.BestSnapAnchor( evt->Position(), layers );
 
         if( TOOL_EVT_UTILS::IsCancelInteractive( *evt ) )
         {
@@ -1489,12 +1499,12 @@ int DRAWING_TOOL::drawZone( bool aKeepout, ZONE_MODE aMode )
 }
 
 
-void DRAWING_TOOL::make45DegLine( DRAWSEGMENT* aSegment, DRAWSEGMENT* aHelper ) const
+void DRAWING_TOOL::make45DegLine( DRAWSEGMENT* aSegment, DRAWSEGMENT* aHelper,
+                                  VECTOR2I& aPos ) const
 {
-    VECTOR2I    cursorPos = m_controls->GetCursorPosition();
     VECTOR2I    origin( aSegment->GetStart() );
-    DIRECTION_45 direction( origin - cursorPos );
+    DIRECTION_45 direction( origin - aPos );
-    SHAPE_LINE_CHAIN newChain = direction.BuildInitialTrace( origin, cursorPos );
+    SHAPE_LINE_CHAIN newChain = direction.BuildInitialTrace( origin, aPos );
 
     if( newChain.PointCount() > 2 )
     {
@@ -1504,9 +1514,9 @@ void DRAWING_TOOL::make45DegLine( DRAWSEGMENT* aSegment, DRAWSEGMENT* aHelper )
     }
     else
     {
-        aSegment->SetEnd( wxPoint( cursorPos.x, cursorPos.y ) );
+        aSegment->SetEnd( wxPoint( aPos.x, aPos.y ) );
-        aHelper->SetStart( wxPoint( cursorPos.x, cursorPos.y ) );
+        aHelper->SetStart( wxPoint( aPos.x, aPos.y ) );
-        aHelper->SetEnd( wxPoint( cursorPos.x, cursorPos.y ) );
+        aHelper->SetEnd( wxPoint( aPos.x, aPos.y ) );
     }
 }
 
@@ -1593,13 +1603,7 @@ int DRAWING_TOOL::DrawVia( const TOOL_EVENT& aEvent )
 
 //          bool do_snap = ( m_frame->Settings().m_magneticTracks == CAPTURE_CURSOR_IN_TRACK_TOOL
 //                || m_frame->Settings().m_magneticTracks == CAPTURE_ALWAYS );
-            bool do_snap = true;
+            m_gridHelper.SetSnap( !( m_modifiers & MD_SHIFT ) );
-
-            if( m_modifiers & MD_SHIFT )
-                do_snap = !do_snap;
-
-            if( do_snap )
-            {
             auto    via = static_cast<VIA*>( aItem );
             wxPoint pos = via->GetPosition();
             TRACK*  track = findTrack( via );
@@ -1612,7 +1616,6 @@ int DRAWING_TOOL::DrawVia( const TOOL_EVENT& aEvent )
                 aItem->SetPosition( wxPoint( snap.x, snap.y ) );
             }
         }
-        }
 
         void PlaceItem( BOARD_ITEM* aItem, BOARD_COMMIT& aCommit ) override
         {

pcbnew/tools/drawing_tool.h

@@ -251,8 +251,9 @@ private:
      * the end of the aSegment is modified according to the current cursor position.
      * @param aSegment is the segment that is currently drawn.
      * @param aHelper is a helper line that shows the next possible segment.
+     * @param aPos is the position of the cursor for this event
      */
-    void make45DegLine( DRAWSEGMENT* aSegment, DRAWSEGMENT* aHelper ) const;
+    void make45DegLine( DRAWSEGMENT* aSegment, DRAWSEGMENT* aHelper, VECTOR2I& aPos ) const;
 
     /**
      * Function constrainDimension()

pcbnew/tools/edit_tool.cpp

@@ -372,6 +372,8 @@ int EDIT_TOOL::Main( const TOOL_EVENT& aEvent )
     // Main loop: keep receiving events
     do
     {
+        grid.SetSnap( !evt->Modifier( MD_SHIFT ) );
+
         if( evt->IsAction( &PCB_ACTIONS::editActivate ) ||
             evt->IsAction( &PCB_ACTIONS::move ) ||
             evt->IsMotion() || evt->IsDrag( BUT_LEFT ) )

pcbnew/tools/grid_helper.cpp

@@ -46,6 +46,8 @@ GRID_HELPER::GRID_HELPER( PCB_BASE_FRAME* aFrame ) :
     m_frame( aFrame )
 {
     m_diagonalAuxAxesEnable = true;
+    m_enableSnap = true;
+    m_snapSize = 100;
     KIGFX::VIEW* view = m_frame->GetGalCanvas()->GetView();
 
     m_viewAxis.SetSize( 20000 );
@@ -141,6 +143,9 @@ VECTOR2I GRID_HELPER::AlignToSegment( const VECTOR2I& aPoint, const SEG& aSeg )
 {
     OPT_VECTOR2I pts[6];
 
+    if( !m_enableSnap )
+        return aPoint;
+
     const VECTOR2D gridOffset( GetOrigin() );
     const VECTOR2D gridSize( GetGrid() );
 
@@ -238,9 +243,22 @@ std::set<BOARD_ITEM*> GRID_HELPER::queryVisible( const BOX2I& aArea ) const
 
 
 VECTOR2I GRID_HELPER::BestSnapAnchor( const VECTOR2I& aOrigin, BOARD_ITEM* aDraggedItem )
+{
+    LSET layers;
+
+    if( aDraggedItem )
+        layers = aDraggedItem->GetLayer();
+    else
+        layers = LSET::AllLayersMask();
+
+    return BestSnapAnchor( aOrigin, layers );
+}
+
+
+VECTOR2I GRID_HELPER::BestSnapAnchor( const VECTOR2I& aOrigin, LSET& aLayers )
 {
     double worldScale = m_frame->GetGalCanvas()->GetGAL()->GetWorldScale();
-    int snapRange = (int) ( 100.0 / worldScale );
+    int snapRange = (int) ( m_snapSize / worldScale );
 
     BOX2I bb( VECTOR2I( aOrigin.x - snapRange / 2, aOrigin.y - snapRange / 2 ), VECTOR2I( snapRange, snapRange ) );
 
@@ -251,19 +269,12 @@ VECTOR2I GRID_HELPER::BestSnapAnchor( const VECTOR2I& aOrigin, BOARD_ITEM* aDrag
         computeAnchors( item, aOrigin );
     }
 
-    LSET layers;
+    ANCHOR* nearest = nearestAnchor( aOrigin, CORNER | SNAPPABLE, aLayers );
-
-    if( aDraggedItem )
-        layers = aDraggedItem->GetLayer();
-    else
-        layers = LSET::AllLayersMask();
-
-    ANCHOR* nearest = nearestAnchor( aOrigin, CORNER | SNAPPABLE, layers );
 
     VECTOR2I nearestGrid = Align( aOrigin );
     double gridDist = ( nearestGrid - aOrigin ).EuclideanNorm();
 
-    if( nearest )
+    if( nearest && m_enableSnap )
     {
         double snapDist = nearest->Distance( aOrigin );
 

pcbnew/tools/grid_helper.h

@@ -57,6 +57,12 @@ public:
 
     VECTOR2I BestDragOrigin( const VECTOR2I& aMousePos, BOARD_ITEM* aItem );
     VECTOR2I BestSnapAnchor( const VECTOR2I& aOrigin, BOARD_ITEM* aDraggedItem );
+    VECTOR2I BestSnapAnchor( const VECTOR2I& aOrigin, LSET& aLayers );
+
+    void SetSnap( bool aSnap )
+    {
+        m_enableSnap = aSnap;
+    }
 
 private:
     enum ANCHOR_FLAGS {
@@ -79,8 +85,6 @@ private:
         {
             return ( aP - pos ).EuclideanNorm();
         }
-
-        //bool CanSnapItem( const BOARD_ITEM* aItem ) const;
     };
 
     std::vector<ANCHOR> m_anchors;
@@ -103,8 +107,13 @@ private:
 
     PCB_BASE_FRAME* m_frame;
     OPT<VECTOR2I> m_auxAxis;
-    bool m_diagonalAuxAxesEnable;
+
-    KIGFX::ORIGIN_VIEWITEM m_viewSnapPoint, m_viewAxis;
+    bool m_diagonalAuxAxesEnable;   ///< If true, use the aux axis for snapping as well
+    bool m_enableSnap;              ///< If true, allow snapping to other items on the layers
+    int m_snapSize;                 ///< Sets the radius in screen units for snapping to items
+
+    KIGFX::ORIGIN_VIEWITEM m_viewSnapPoint;
+    KIGFX::ORIGIN_VIEWITEM m_viewAxis;
 };
 
 #endif

pcbnew/tools/point_editor.cpp

@@ -329,6 +329,8 @@ int POINT_EDITOR::OnSelectionChange( const TOOL_EVENT& aEvent )
         if( revert )
             break;
 
+        grid.SetSnap( !evt->Modifier( MD_SHIFT ) );
+
         if( !m_editPoints ||
             evt->Matches( m_selectionTool->ClearedEvent ) ||
             evt->Matches( m_selectionTool->UnselectedEvent ) ||
@@ -346,7 +348,6 @@ int POINT_EDITOR::OnSelectionChange( const TOOL_EVENT& aEvent )
             {
                 commit.StageItems( selection, CHT_MODIFY );
 
-                controls->ForceCursorPosition( false );
                 m_original = *m_editedPoint;    // Save the original position
                 controls->SetAutoPan( true );
                 modified = true;
@@ -358,14 +359,14 @@ int POINT_EDITOR::OnSelectionChange( const TOOL_EVENT& aEvent )
             if( enableAltConstraint != (bool) m_altConstraint )  // alternative constraint
                 setAltConstraint( enableAltConstraint );
 
-            m_editedPoint->SetPosition( controls->GetCursorPosition() );
-
             if( m_altConstraint )
                 m_altConstraint->Apply();
             else
                 m_editedPoint->ApplyConstraint();
 
-            m_editedPoint->SetPosition( grid.Align( m_editedPoint->GetPosition() ) );
+
+            m_editedPoint->SetPosition( grid.BestSnapAnchor( evt->Position(),
+                    static_cast<BOARD_ITEM*>( item ) ) );
             updateItem();
             updatePoints();
         }