/// <summary>
/// 鼠标移动正切？如果m_tanSnap.Owner is IArc，则设置端点P1为圆上的切点，p2为传入的值，如果p1为空，则设置p1p2均为圆弧的中点
/// </summary>
/// <param name="canvas"></param>
/// <param name="point"></param>
protected virtual void MouseMoveTangent(ICanvas canvas, UnitPoint point)
{
if (m_tanSnap.Owner is IArc)
{
IArc src = m_tanSnap.Owner as IArc;
m_p1 = HitUtil.TangentPointOnCircle(src.Center, src.Radius, point, m_tanReverse);
m_p2 = point;
if (m_p1 == UnitPoint.Empty)
{
m_p2 = m_p1 = src.Center;
}
}
}
public virtual ISnapPoint SnapPoint(ICanvas canvas, UnitPoint point, List <IDrawObject> otherobj, Type[] runningsnaptypes, Type usersnaptype)
{
float thWidth = Line.ThresholdWidth(canvas, Width, ThresholdPixel);
if (runningsnaptypes != null)
{
foreach (Type snaptype in runningsnaptypes)
{
if (snaptype == typeof(QuadrantSnapPoint))
{
UnitPoint p = HitUtil.NearestPointOnCircle(m_center, m_radius, point, 90);
if (p != UnitPoint.Empty && HitUtil.PointInPoint(p, point, thWidth))
{
return(new QuadrantSnapPoint(canvas, this, p));
}
}
//if (snaptype == typeof(DivisionSnapPoint))
//{
// double angle = 360 / 8;
// UnitPoint p = HitUtil.NearestPointOnCircle(m_center, m_radius, point, angle);
// if (p != UnitPoint.Empty && HitUtil.PointInPoint(p, point, thWidth))
// return new DivisionSnapPoint(canvas, this, p);
//}
if (snaptype == typeof(CenterSnapPoint))
{
if (HitUtil.PointInPoint(m_center, point, thWidth))
{
return(new CenterSnapPoint(canvas, this, m_center));
}
}
if (snaptype == typeof(VertextSnapPoint))
{
if (HitUtil.PointInPoint(P1, point, thWidth))
{
return(new VertextSnapPoint(canvas, this, P1));
}
if (HitUtil.PointInPoint(P3, point, thWidth))
{
return(new VertextSnapPoint(canvas, this, P3));
}
}
}
return(null);
}
if (usersnaptype == typeof(NearestSnapPoint))
{
UnitPoint p = HitUtil.NearestPointOnCircle(m_center, m_radius, point, 0);
if (p != UnitPoint.Empty)
{
return(new NearestSnapPoint(canvas, this, p));
}
}
if (usersnaptype == typeof(PerpendicularSnapPoint))
{
UnitPoint p = HitUtil.NearestPointOnCircle(m_center, m_radius, point, 0);
if (p != UnitPoint.Empty)
{
return(new PerpendicularSnapPoint(canvas, this, p));
}
}
if (usersnaptype == typeof(QuadrantSnapPoint))
{
UnitPoint p = HitUtil.NearestPointOnCircle(m_center, m_radius, point, 90);
if (p != UnitPoint.Empty)
{
return(new QuadrantSnapPoint(canvas, this, p));
}
}
if (usersnaptype == typeof(TangentSnapPoint))
{
IDrawObject drawingObject = canvas.CurrentObject;
UnitPoint p = UnitPoint.Empty;
if (drawingObject is LineEdit)
{
UnitPoint mousepoint = point;
point = ((LineEdit)drawingObject).P1;
UnitPoint p1 = HitUtil.TangentPointOnCircle(m_center, m_radius, point, false);
UnitPoint p2 = HitUtil.TangentPointOnCircle(m_center, m_radius, point, true);
double d1 = HitUtil.Distance(mousepoint, p1);
double d2 = HitUtil.Distance(mousepoint, p2);
if (d1 <= d2)
{
return(new TangentSnapPoint(canvas, this, p1));
}
else
{
return(new TangentSnapPoint(canvas, this, p2));
}
}
//if (p != PointF.Empty)
return(new TangentSnapPoint(canvas, this, p));
}
if (usersnaptype == typeof(CenterSnapPoint))
{
return(new CenterSnapPoint(canvas, this, m_center));
}
return(null);
}