Snap to eeschema lines

Allows easier snapping to lines when drawing in eeschema.

Fixes https://gitlab.com/kicad/code/kicad/issues/7378

common/tool/grid_helper.cpp

@@ -35,6 +35,7 @@ using namespace std::placeholders;
 GRID_HELPER::GRID_HELPER( TOOL_MANAGER* aToolMgr ) :
     m_toolMgr( aToolMgr )
 {
+    m_maskTypes = ALL;
     m_enableSnap = true;
     m_enableSnapLine = true;
     m_enableGrid = true;

eeschema/tools/ee_grid_helper.cpp

@@ -25,8 +25,10 @@
 
 #include <functional>
 #include <sch_item.h>
+#include <sch_line.h>
 #include <sch_painter.h>
 #include <tool/tool_manager.h>
+#include <trigo.h>
 #include <view/view.h>
 #include "ee_grid_helper.h"
 
@@ -257,25 +259,25 @@ std::set<SCH_ITEM*> EE_GRID_HELPER::queryVisible( const BOX2I& aArea,
 }
 
 
-void EE_GRID_HELPER::computeAnchors( SCH_ITEM* aItem, const VECTOR2I& aRefPos, bool aFrom )
+void EE_GRID_HELPER::computeAnchors( SCH_ITEM *aItem, const VECTOR2I &aRefPos, bool aFrom )
 {
-    switch( aItem->Type() )
+    switch ( aItem->Type() )
     {
     case SCH_COMPONENT_T:
-    case SCH_SHEET_T:
+        case SCH_SHEET_T:
         addAnchor( aItem->GetPosition(), ORIGIN, aItem );
         KI_FALLTHROUGH;
     case SCH_JUNCTION_T:
-    case SCH_NO_CONNECT_T:
-    case SCH_LINE_T:
-    case SCH_GLOBAL_LABEL_T:
-    case SCH_HIER_LABEL_T:
-    case SCH_LABEL_T:
-    case SCH_BUS_WIRE_ENTRY_T:
-    {
+        case SCH_NO_CONNECT_T:
+        case SCH_LINE_T:
+        case SCH_GLOBAL_LABEL_T:
+        case SCH_HIER_LABEL_T:
+        case SCH_LABEL_T:
+        case SCH_BUS_WIRE_ENTRY_T:
+        {
         std::vector<wxPoint> pts = aItem->GetConnectionPoints();
 
-        for( const wxPoint& pt : pts )
+        for( const wxPoint &pt : pts )
             addAnchor( VECTOR2I( pt ), SNAPPABLE | CORNER, aItem );
 
         break;
@@ -283,7 +285,28 @@ void EE_GRID_HELPER::computeAnchors( SCH_ITEM* aItem, const VECTOR2I& aRefPos, b
 
     default:
         break;
-   }
+    }
+
+    if( SCH_LINE* line = dyn_cast<SCH_LINE*>( aItem ) )
+    {
+        VECTOR2I pt = m_enableGrid ? Align( aRefPos ) : aRefPos;
+
+        if( line->GetStartPoint().x == line->GetEndPoint().x )
+        {
+            VECTOR2I possible( line->GetStartPoint().x, pt.y );
+
+            if( TestSegmentHit( wxPoint( possible ), line->GetStartPoint(), line->GetEndPoint(), 0 ) )
+                addAnchor( possible, SNAPPABLE | VERTICAL, aItem );
+        }
+        else if( line->GetStartPoint().y == line->GetEndPoint().y )
+        {
+            VECTOR2I possible( pt.x, line->GetStartPoint().y );
+
+            if( TestSegmentHit( wxPoint( possible ), line->GetStartPoint(), line->GetEndPoint(), 0 ) )
+                addAnchor( possible, SNAPPABLE | HORIZONTAL, aItem );
+        }
+
+    }
 }
 
 

eeschema/tools/sch_line_wire_bus_tool.cpp

@@ -508,13 +508,23 @@ int SCH_LINE_WIRE_BUS_TOOL::doDrawSegments( const std::string& aTool, int aType,
     while( TOOL_EVENT* evt = Wait() )
     {
         setCursor();
+        grid.SetMask( GRID_HELPER::ALL );
         grid.SetSnap( !evt->Modifier( MD_SHIFT ) );
         grid.SetUseGrid( getView()->GetGAL()->GetGridSnapping() && !evt->Modifier( MD_ALT ) );
 
+        if( segment )
+        {
+            if( segment->GetStartPoint().x == segment->GetEndPoint().x )
+                grid.ClearMaskFlag( GRID_HELPER::VERTICAL );
+
+            if( segment->GetStartPoint().y == segment->GetEndPoint().y )
+                grid.ClearMaskFlag( GRID_HELPER::HORIZONTAL );
+        }
+
         wxPoint cursorPos = evt->IsPrime() ? (wxPoint) evt->Position()
                                            : (wxPoint) controls->GetMousePosition();
 
-        cursorPos = (wxPoint) grid.BestSnapAnchor( cursorPos, LAYER_CONNECTABLE, nullptr );
+        cursorPos = (wxPoint) grid.BestSnapAnchor( cursorPos, LAYER_CONNECTABLE, segment );
         controls->ForceCursorPosition( true, cursorPos );
 
         bool forceHV = m_frame->eeconfig()->m_Drawing.hv_lines_only;

include/tool/grid_helper.h

@@ -36,7 +36,7 @@ class GRID_HELPER
 {
 public:
     GRID_HELPER( TOOL_MANAGER* aToolMgr );
-    ~GRID_HELPER();
+    virtual ~GRID_HELPER();
 
     VECTOR2I GetGrid() const;
     VECTOR2I GetOrigin() const;
@@ -68,16 +68,22 @@ public:
 
     void SetSnapLine( bool aSnap ) { m_enableSnapLine = aSnap; }
 
-protected:
+    void SetMask( int aMask ) { m_maskTypes = aMask; }
+    void SetMaskFlag( int aFlag ) { m_maskTypes |= aFlag; }
+    void ClearMaskFlag( int aFlag ) { m_maskTypes = m_maskTypes & ~aFlag; }
+
     enum ANCHOR_FLAGS {
         CORNER = 1,
         OUTLINE = 2,
         SNAPPABLE = 4,
         ORIGIN = 8,
         VERTICAL = 16,
-        HORIZONTAL = 32
+        HORIZONTAL = 32,
+        ALL = CORNER | OUTLINE | SNAPPABLE | ORIGIN | VERTICAL | HORIZONTAL
     };
 
+protected:
+
     struct ANCHOR
     {
         ANCHOR( VECTOR2I aPos, int aFlags = CORNER | SNAPPABLE, EDA_ITEM* aItem = NULL ) :
@@ -98,7 +104,8 @@ protected:
 
     void addAnchor( const VECTOR2I& aPos, int aFlags, EDA_ITEM* aItem )
     {
-        m_anchors.emplace_back( ANCHOR( aPos, aFlags, aItem ) );
+        if( ( aFlags & m_maskTypes ) == aFlags )
+            m_anchors.emplace_back( ANCHOR( aPos, aFlags, aItem ) );
     }
 
     void clearAnchors()
@@ -112,6 +119,8 @@ protected:
     TOOL_MANAGER*          m_toolMgr;
     OPT<VECTOR2I>          m_auxAxis;
 
+    int                    m_maskTypes;      // Mask of allowed snap types
+
     bool                   m_enableSnap;     // Allow snapping to other items on the layers
     bool                   m_enableGrid;     // If true, allow snapping to grid
     bool                   m_enableSnapLine; // Allow drawing lines from snap points