From cd738297b072e556164e52fecb701ef9283d89f2 Mon Sep 17 00:00:00 2001
From: Oliver Walters <oliver.henry.walters@gmail.com>
Date: Tue, 9 May 2017 17:28:54 +1000
Subject: [PATCH] SELECTION_AREA color now indicates selection mode

BLUE = Normal
GREEN = Addition
RED = Subtraction

Line color indicates "window" or "crossing" selection mode
---
 common/preview_items/selection_area.cpp | 49 +++++++++++++++++++++----
 include/preview_items/selection_area.h  | 10 +++++
 pcbnew/tools/selection_tool.cpp         |  7 ++--
 3 files changed, 55 insertions(+), 11 deletions(-)

diff --git a/common/preview_items/selection_area.cpp b/common/preview_items/selection_area.cpp
index 001e6df6a3..ecee3c386e 100644
--- a/common/preview_items/selection_area.cpp
+++ b/common/preview_items/selection_area.cpp
@@ -30,16 +30,36 @@
 using namespace KIGFX::PREVIEW;
 
 // Selection area colours
-const COLOR4D SELECT_COLOR_L2R( 0.3, 0.3, 0.6, 0.3 );  // Slight blue
-const COLOR4D SELECT_COLOR_R2L( 0.3, 0.6, 0.3, 0.3 );  // Slight green
+const COLOR4D SELECT_MODE_NORMAL( 0.3, 0.3, 0.7, 0.3 ); // Slight blue
+const COLOR4D SELECT_MODE_ADDITIVE( 0.3, 0.7, 0.3, 0.3 ); // Slight green
+const COLOR4D SELECT_MODE_SUBTRACT( 0.7, 0.3, 0.3, 0.3 ); // Slight red
 
+const COLOR4D SELECT_OUTLINE_L2R( 1.0, 1.0, 0.4, 1.0 );
+const COLOR4D SELECT_OUTLINE_R2L( 0.4, 0.4, 1.0, 1.0 );
 
-SELECTION_AREA::SELECTION_AREA()
+SELECTION_AREA::SELECTION_AREA() :
+        m_additive( false ),
+        m_subtractive( false )
 {
-    SetStrokeColor( COLOR4D( 1.0, 1.0, 0.4, 1.0 ) );
-    SetFillColor( COLOR4D( 0.3, 0.3, 0.5, 0.3 ) );
+    SetStrokeColor( SELECT_OUTLINE_L2R );
+    SetFillColor( SELECT_MODE_NORMAL );
 }
 
+void SELECTION_AREA::SetAdditive( bool aAdditive )
+{
+    m_additive = aAdditive;
+
+    if( m_additive )
+        m_subtractive = false;
+}
+
+void SELECTION_AREA::SetSubtractive( bool aSubtractive )
+{
+    m_subtractive = aSubtractive;
+
+    if ( m_subtractive )
+        m_additive = false;
+}
 
 const BOX2I SELECTION_AREA::ViewBBox() const
 {
@@ -54,8 +74,23 @@ const BOX2I SELECTION_AREA::ViewBBox() const
 
 void SELECTION_AREA::drawPreviewShape( KIGFX::GAL& aGal ) const
 {
-    // Set the fill color based on the direction of selection
-    aGal.SetFillColor( ( m_origin.x <= m_end.x ) ? SELECT_COLOR_L2R : SELECT_COLOR_R2L );
+    // Set the fill of the selection rectangle
+    // based on the selection mode
+    if( m_additive )
+    {
+        aGal.SetFillColor( SELECT_MODE_ADDITIVE );
+    }
+    else if( m_subtractive )
+    {
+        aGal.SetFillColor( SELECT_MODE_SUBTRACT );
+    }
+    else
+    {
+        aGal.SetFillColor( SELECT_MODE_NORMAL );
+    }
+
+    // Set the stroke color to indicate window or crossing selection
+    aGal.SetStrokeColor( ( m_origin.x <= m_end.x ) ? SELECT_OUTLINE_L2R : SELECT_OUTLINE_R2L );
 
     aGal.DrawRectangle( m_origin, m_end );
 }
diff --git a/include/preview_items/selection_area.h b/include/preview_items/selection_area.h
index d45924bd6e..a2b1db2059 100644
--- a/include/preview_items/selection_area.h
+++ b/include/preview_items/selection_area.h
@@ -80,8 +80,18 @@ public:
 
     VECTOR2I GetEnd() const { return m_end; }
 
+    bool IsAdditive() const { return m_additive; }
+    bool IsSubtractive() const { return m_subtractive; }
+
+    void SetAdditive( bool aAdditive );
+    void SetSubtractive( bool aSubtractive );
+
+
 private:
 
+    bool m_additive;
+    bool m_subtractive;
+
     /**
      * Draw the selection rectangle onto the GAL
      */
diff --git a/pcbnew/tools/selection_tool.cpp b/pcbnew/tools/selection_tool.cpp
index ec4e980a47..dd339f3f7d 100644
--- a/pcbnew/tools/selection_tool.cpp
+++ b/pcbnew/tools/selection_tool.cpp
@@ -488,14 +488,13 @@ bool SELECTION_TOOL::selectMultiple()
 
         if( evt->IsDrag( BUT_LEFT ) )
         {
-            if( !m_additive && !m_subtractive )
-            {
-                clearSelection();
-            }
 
             // Start drawing a selection box
             area.SetOrigin( evt->DragOrigin() );
             area.SetEnd( evt->Position() );
+            area.SetAdditive( m_additive );
+            area.SetSubtractive( m_subtractive );
+
             view->SetVisible( &area, true );
             view->Update( &area );
         }