protected Coordinate SnapToSelection(Coordinate c, Viewport2D vp)
{
if (!Document.Map.SnapToGrid) return c;
var snap = (Select.SnapStyle == SnapStyle.SnapOnAlt && KeyboardState.Alt) ||
(Select.SnapStyle == SnapStyle.SnapOffAlt && !KeyboardState.Alt);
if (!snap) return c;
var snapped = c.Snap(Document.Map.GridSpacing);
if (Document.Selection.InFaceSelection || Document.Selection.IsEmpty()) return snapped;
// Try and snap the the selection box center
var selBox = Document.Selection.GetSelectionBoundingBox();
var selCenter = vp.Flatten(selBox.Center);
if (DMath.Abs(selCenter.X - c.X) < selBox.Width / 10 && DMath.Abs(selCenter.Y - c.Y) < selBox.Height / 10) return selCenter;
var objects = Document.Selection.GetSelectedObjects().ToList();
// Try and snap to an object center
foreach (var mo in objects)
{
if (!(mo is Entity) && !(mo is Solid)) continue;
var center = vp.Flatten(mo.BoundingBox.Center);
if (DMath.Abs(center.X - c.X) >= mo.BoundingBox.Width / 10) continue;
if (DMath.Abs(center.Y - c.Y) >= mo.BoundingBox.Height / 10) continue;
return center;
}
// Get all the edges of the selected objects
var lines = objects.SelectMany(x =>
{
if (x is Entity) return x.BoundingBox.GetBoxLines();
if (x is Solid) return ((Solid) x).Faces.SelectMany(f => f.GetLines());
return new Line[0];
}).Select(x => new Line(vp.Flatten(x.Start), vp.Flatten(x.End))).ToList();
// Try and snap to an edge
var closest = snapped;
foreach (var line in lines)
{
// if the line and the grid are in the same spot, return the snapped point
if (line.ClosestPoint(snapped).EquivalentTo(snapped)) return snapped;
// Test for corners and midpoints within a 10% tolerance
var pointTolerance = (line.End - line.Start).VectorMagnitude() / 10;
if ((line.Start - c).VectorMagnitude() < pointTolerance) return line.Start;
if ((line.End - c).VectorMagnitude() < pointTolerance) return line.End;
var center = (line.Start + line.End) / 2;
if ((center - c).VectorMagnitude() < pointTolerance) return center;
// If the line is closer to the grid point, return the line
var lineSnap = line.ClosestPoint(c);
if ((closest - c).VectorMagnitude() > (lineSnap - c).VectorMagnitude()) closest = lineSnap;
}
return closest;
}
public Coordinate Snap(Coordinate c, decimal spacing = 0)
{
if (!Map.SnapToGrid) return c;
var snap = (Select.SnapStyle == SnapStyle.SnapOnAlt && KeyboardState.Alt) ||
(Select.SnapStyle == SnapStyle.SnapOffAlt && !KeyboardState.Alt);
return snap ? c.Snap(spacing == 0 ? Map.GridSpacing : spacing) : c;
}