/// <summary>
/// Calculates the position of the extension point.
/// </summary>
/// <returns>The calculated position</returns>
IPosition Calculate()
{
// Figure out the new position for the extension point, depending
// on whether the line we extended is a circular arc or a straight.
IPosition start; // Start of the extension
IPosition end; // End of the extension
bool ok; // Did calculation work ok?
if (m_ExtendLine is ArcFeature)
{
IPosition center; // The center of the circle
bool iscw; // Is the curve clockwise?
ok = LineExtensionUI.Calculate(m_ExtendLine, m_IsExtendFromEnd, m_Length,
out start, out end, out center, out iscw);
}
else
{
ok = LineExtensionUI.Calculate(m_ExtendLine, m_IsExtendFromEnd, m_Length,
out start, out end);
}
return(ok ? end : null);
}
internal void Draw()
{
ISpatialDisplay display = m_Cmd.ActiveDisplay;
// Draw the line we're extending in a special colour (any highlighting it
// originally had should have been removed during LineExtensionControl_Load)
if (m_ExtendLine != null)
{
m_ExtendLine.Draw(display, Color.DarkBlue);
}
// If we're doing an update, draw the original extension in grey.
LineExtensionOperation pop = UpdateOp;
if (pop != null)
{
LineFeature origLine = pop.NewLine;
if (origLine != null)
{
origLine.Draw(display, Color.Gray);
}
PointFeature origPoint = pop.NewPoint;
if (origPoint != null)
{
origPoint.Draw(display, Color.Gray);
}
}
// Calculate the start and end points of the extension, initially
// assuming that it's a straight line extension.
IPosition start, end;
if (LineExtensionUI.Calculate(m_ExtendLine, m_IsExtendFromEnd, m_Length, out start, out end))
{
// Draw the straight extension line
IDrawStyle style = (m_WantLine ? new DrawStyle(Color.Magenta) : new DottedStyle(Color.Magenta));
LineSegmentGeometry seg = new LineSegmentGeometry(start, end);
seg.Render(display, style);
}
else
{
// Perhaps it's a circular arc ...
IPosition center;
bool iscw;
if (LineExtensionUI.Calculate(m_ExtendLine, m_IsExtendFromEnd, m_Length,
out start, out end, out center, out iscw))
{
// And draw the curve.
IDrawStyle style = (m_WantLine ? new DrawStyle(Color.Magenta) : new DottedStyle(Color.Magenta));
IPointGeometry c = PointGeometry.Create(center);
CircularArcGeometry arc = new CircularArcGeometry(c, start, end, iscw);
arc.Render(display, style);
}
else if (m_ExtendLine != null)
{
// Get the position we're extending from.
end = (m_IsExtendFromEnd ? m_ExtendLine.EndPoint : m_ExtendLine.StartPoint);
}
}
// If we actually got something, draw the end point.
if (end != null)
{
IDrawStyle style = m_Cmd.Controller.DrawStyle;
style.FillColor = Color.Magenta;
style.Render(display, end);
}
}