// This script draws an Archimedean spiral.

function OnMenu()
{
  // Adds the command in the menu for graphic documents.
  DlxApp.GetMenu(DlxApp.MENU_DWG).AddCommand("Draw Spiral", 100, "Activate the tool to draw a spiral. ");

  // Adds the command in the menu for schematics.
  DlxApp.GetMenu(DlxApp.MENU_SCH).AddCommand("Draw Spiral", 100, "Activate the tool to draw a spiral. ");
}

function OnMenuUpdateCommand(cmd)
{
  switch (cmd.GetCommandId())
  {
    case 100:
    {
      var layer = DlxApp.GetActiveLayer();
      cmd.Enable(layer.IsValid() && (layer.GetType() == DlxApp.LAYERTYPE_DRAWING));
    }; break;
  }
}

function OnMenuCommand(cmdId)
{
  switch (cmdId)
  {
  case 100:
    DrawSpiral();
    break;
  }
} 

function OnToolPickPoint(toolId, points)
{
  if (toolId == 0)
  {
    // The tool to capture the center of the spiral and the distance between loops.
    if (points.length == 1)
      DlxVariables.SetVar("ToolPickPoint_Msg", DlxApp.Format("Center of the spiral: X=%.3f Y=%.3f", points[0].x, points[0].y));
    else
      DlxVariables.SetVar("ToolPickPoint_Msg", DlxApp.Format("Distance between loops: %.3f", points[0].Distance(points[1])));
  }

  if (toolId == 1)
  {
    // The tool to acquire the spiral radius.
    var shape = DlxVariables.GetVar("shape");
    var radius = points[0].Distance(points[1]);
    var centerAndSpacing = DlxVariables.GetVar("centerAndSpacing");
    DlxVariables.SetVar("ToolPickPoint_Msg", DlxApp.Format("Radius of the spiral: %.3f", radius));
    BuildArchimedeanSpiral(shape, centerAndSpacing.p1, centerAndSpacing.Length(), points[0].ArcAngle(points[1]), radius, 10);
  }
}

function BuildArchimedeanSpiral(shape, center, spacing, angleOffset, radiusMax, chordDegrees)
{
  var fig = shape.GetFigure();
  fig.BeginShape();

  angleOffset = angleOffset / 180 * Math.PI;
  var A = spacing / (Math.PI * 2);
  var dtheta = (chordDegrees / 180 * Math.PI);
  for (var theta = 0; ; theta += dtheta)
  {
    var r = A * theta;
    var point = new DlxPoint();
    point.x = (r * Math.cos(theta + angleOffset)) + center.x;
    point.y = (r * Math.sin(theta + angleOffset)) + center.y;
    fig.AddPoint(point);
    if (r > radiusMax) 
      break;
  }

  fig.EndShape(false);
}

function DrawSpiral()
{
  var layer = DlxApp.GetActiveLayer();
  if ((layer.IsValid()) && (layer.GetType() == DlxApp.LAYERTYPE_DRAWING))
  {
     var page = layer.GetPage();
     var doc = layer.GetDocument();

     // Clear current selection.
     var selection = page.GetSelection();
     selection.Empty();

     // Activate the tool to capture the center of the spiral and the distance between loops.
     var centerAndSpacing = doc.ToolPickPoint(0, 2);
     if ((centerAndSpacing.IsValid()) && (centerAndSpacing.Length() >= 0.1))
     {
       // Create a DlxShape object.
       var shape = layer.DrawShape();

       // Turn off undo registrations. This prevents changes to the shape object 
       // from being recorded in the next step of acquiring the spiral radius. 
       page.EnableUndo(false, false);

       // Saves the useful data for the subsequent phase of acquiring the spiral radius.
       DlxVariables.SetVar("shape", shape);
       DlxVariables.SetVar("centerAndSpacing", centerAndSpacing);

       // Activate the tool to acquire the spiral radius.
       // In this phase, the OnToolPickPoint function is called at each mouse movement.
       var radius = doc.ToolPickPoint(1, 2, DlxApp.TOOLPICKPOINT_SHOWLAST, "", centerAndSpacing.p1);
       if ((radius.IsValid()) && (radius.Length() >= 0.1))
       {
         // The data is valid. Draw the spiral and select it. 
         BuildArchimedeanSpiral(shape, centerAndSpacing.p1, centerAndSpacing.Length(), radius.ArcAngle(), radius.Length(), 5);
         selection.AddObject(shape);
       }
       else
       {
         // The operation was canceled or the data is invalid. Delete the DlxShape object. 
         selection.AddObject(shape);
         selection.Delete();
       }

       // Turn on undo registrations.
       page.EnableUndo(true);
    }
  }
}