/// <summary>
/// Returns the inverse rotation matrix for the given node and the current angle.
/// </summary>
private Matrix2D GetInverseRotationMatrix(INode node)
{
var center = node.Layout.GetCenter();
if (!(center.Equals(inverseMatrixCenter)) || Angle != inverseMatrixAngle)
{
inverseMatrix.Reset();
inverseMatrix.Rotate(CachingOrientedRectangle.ToRadians(-Angle), center);
inverseMatrixCenter = center;
inverseMatrixAngle = Angle;
}
return(inverseMatrix);
}
/// <summary>
/// Snaps the angle to the rotation angles of other nodes and the coordinate axes.
/// </summary>
/// <remarks>
/// Angles near such an angle are replaced with this angle.
/// </remarks>
private double SnapAngle(IInputModeContext context, double angle)
{
// Check for disabled snapping
var snapContext = context.Lookup <SnapContext>();
if (snapContext != null && !snapContext.Enabled)
{
return(angle);
}
// Same angle snapping
if (SnapToSameAngleDelta > 0 && nodeAngles != null)
{
// Find the first angle that is sufficiently similar
var candidate = nodeAngles.Where(na => CachingOrientedRectangle.NormalizeAngle(Math.Abs(na.Item1 - angle)) < SnapToSameAngleDelta).OrderBy(na => na.Item1).FirstOrDefault();
if (candidate != null)
{
// Add highlight to every matching node
var canvas = (GraphControl)context.CanvasControl;
if (sameAngleHighlightedNodes != candidate.Item2)
{
ClearSameAngleHighlights(context);
}
foreach (var matchingNode in candidate.Item2)
{
canvas.HighlightIndicatorManager.AddHighlight(matchingNode);
}
sameAngleHighlightedNodes = candidate.Item2;
return(candidate.Item1);
}
ClearSameAngleHighlights(context);
}
if (SnapDelta <= 0.0 || SnapStep == 0)
{
return(angle);
}
var mod = Math.Abs(angle % SnapStep);
return((mod < SnapDelta || mod > SnapStep - SnapDelta)
? SnapStep * Math.Round(angle / SnapStep)
: angle);
}
/// <summary>
/// Returns the 'snapped' vector for the given up vector.
/// </summary>
/// <remarks>
/// If the vector is almost horizontal or vertical, this method returns the exact horizontal
/// or vertical up vector instead.
/// </remarks>
private static double CalculateAngle(PointD upVector)
{
return(CachingOrientedRectangle.NormalizeAngle(-(Math.Atan2(upVector.Y, upVector.X) / Math.PI * 180 + 90)));
}
