From a5b92a1fe47f589145803a6156639a9b36a5a4c8 Mon Sep 17 00:00:00 2001
From: Seth Hillbrand <hillbrand@ucdavis.edu>
Date: Sat, 2 Jun 2018 21:01:01 -0700
Subject: [PATCH] Constrain dimension tool while creating

The dimension tool is optionally constrained (MD_CTRL) while editing the
dimension.  This ensures same behavior for the creation step.
---
 pcbnew/tools/drawing_tool.cpp | 18 ++++++++++++++++++
 pcbnew/tools/drawing_tool.h   |  7 +++++++
 2 files changed, 25 insertions(+)

diff --git a/pcbnew/tools/drawing_tool.cpp b/pcbnew/tools/drawing_tool.cpp
index 0c771879a9..d2a89feec9 100644
--- a/pcbnew/tools/drawing_tool.cpp
+++ b/pcbnew/tools/drawing_tool.cpp
@@ -461,6 +461,17 @@ int DRAWING_TOOL::PlaceText( const TOOL_EVENT& aEvent )
 }
 
 
+void DRAWING_TOOL::constrainDimension( DIMENSION* dimension )
+{
+    VECTOR2I lineVector( dimension->GetEnd() - dimension->GetOrigin() );
+    double angle = lineVector.Angle();
+    double newAngle = KiROUND( angle / M_PI_4 ) * M_PI_4;
+    VECTOR2I newLineVector = lineVector.Rotate( newAngle - angle );
+
+    dimension->SetEnd( dimension->GetOrigin() + static_cast<wxPoint>( newLineVector ) );
+}
+
+
 int DRAWING_TOOL::DrawDimension( const TOOL_EVENT& aEvent )
 {
     DIMENSION* dimension = NULL;
@@ -571,6 +582,9 @@ int DRAWING_TOOL::DrawDimension( const TOOL_EVENT& aEvent )
             case SET_END:
                 dimension->SetEnd( wxPoint( cursorPos.x, cursorPos.y ) );
 
+                if( !!evt->Modifier( MD_CTRL ) )
+                    constrainDimension( dimension );
+
                 // Dimensions that have origin and end in the same spot are not valid
                 if( dimension->GetOrigin() == dimension->GetEnd() )
                     --step;
@@ -606,6 +620,10 @@ int DRAWING_TOOL::DrawDimension( const TOOL_EVENT& aEvent )
             {
             case SET_END:
                 dimension->SetEnd( wxPoint( cursorPos.x, cursorPos.y ) );
+
+                if( !!evt->Modifier( MD_CTRL ) )
+                    constrainDimension( dimension );
+
                 break;
 
             case SET_HEIGHT:
diff --git a/pcbnew/tools/drawing_tool.h b/pcbnew/tools/drawing_tool.h
index d851c24cb6..3160d07f52 100644
--- a/pcbnew/tools/drawing_tool.h
+++ b/pcbnew/tools/drawing_tool.h
@@ -258,6 +258,13 @@ private:
      */
     void make45DegLine( DRAWSEGMENT* aSegment, DRAWSEGMENT* aHelper ) const;
 
+    /**
+     * Function constrainDimension()
+     * Forces the dimension lime to be drawn on multiple of 45 degrees
+     * @param aDimension is the dimension element currently being drawn
+     */
+    void constrainDimension( DIMENSION* dimension );
+
     ///> Returns the appropriate width for a segment depending on the settings.
     int getSegmentWidth( unsigned int aLayer ) const;