protected override Size MeasureOverride(Size availableSize)
{
var size = new Size();
if (ParentMap != null)
{
var scale = ParentMap.GetScale(ParentMap.Center).X;
var length = MinWidth / scale;
var magnitude = Math.Pow(10d, Math.Floor(Math.Log10(length)));
if (length / magnitude < 2d)
{
length = 2d * magnitude;
}
else if (length / magnitude < 5d)
{
length = 5d * magnitude;
}
else
{
length = 10d * magnitude;
}
size.Width = length * scale + StrokeThickness + Padding.Left + Padding.Right;
size.Height = 1.25 * FontSize + StrokeThickness + Padding.Top + Padding.Bottom;
var x1 = Padding.Left + StrokeThickness / 2d;
var x2 = size.Width - Padding.Right - StrokeThickness / 2d;
var y1 = size.Height / 2d;
var y2 = size.Height - Padding.Bottom - StrokeThickness / 2d;
line.Points = new PointCollection
{
new Point(x1, y1),
new Point(x1, y2),
new Point(x2, y2),
new Point(x2, y1)
};
line.Measure(size);
label.Text = length >= 1000d ? string.Format("{0:0} km", length / 1000d) : string.Format("{0:0} m", length);
label.Width = size.Width;
label.Height = size.Height;
label.Measure(size);
}
return(size);
}