void BuildEndCap(
double x0, double y0,
double x1, double y1,
List <Vector> outputVectors)
{
switch (LineCapStyle)
{
default: throw new NotSupportedException();
case LineCap.Butt:
break;
case LineCap.Square:
break;
case LineCap.Round:
{
//------------------------
//x0,y0 -> end of line 1
//x1,y1 -> end of line 2
//------------------------
double c_x = (x0 + x1) / 2;
double c_y = (y0 + y1) / 2;
Vector2 delta = new Vector2(x1 - c_x, y1 - c_y);
ArcGenerator.GenerateArcNew(outputVectors,
c_x, c_y, delta, AggMath.deg2rad(180));
}
break;
}
}
public void BuildJointVertex(
List <Vector> positiveSideVectors,
List <Vector> negativeSideVectors)
{
if (LineJoinKind == LineJoin.Bevel)
{
return;
}
//--------------------------------------------------------------
Vector2 v0v1 = new Vector2(x1 - x0, y1 - y0);
Vector2 v1v2 = new Vector2(x2 - x1, y2 - y1);
Vector2 delta_v0v1 = v0v1.RotateInDegree(90).NewLength(HalfWidth);
Vector2 delta_v1v2 = v1v2.RotateInDegree(90).NewLength(HalfWidth);
double rad_v0v1 = Math.Atan2(v0v1.y, v0v1.x);
double rad_v1v2 = Math.Atan2(v1v2.y, v1v2.x);
double angle_rad_diff = rad_v1v2 - rad_v0v1;
if (positiveSideVectors != null)
{
Vector2 vec_a = new Vector2(x0 + delta_v0v1.x, y0 + delta_v0v1.y);
Vector2 vec_b = new Vector2(x1 + delta_v0v1.x, y1 + delta_v0v1.y);
Vector2 vec_c = new Vector2(x1 + delta_v1v2.x, y1 + delta_v1v2.y);
Vector2 vec_d = new Vector2(x2 + delta_v1v2.x, y2 + delta_v1v2.y);
Vector2 cutPoint;
if (MyMath.FindCutPoint(
vec_a, vec_b, //a->b
vec_c, vec_d, //b->c
out cutPoint))
{
if (angle_rad_diff > 0)
{
//'ACUTE' angle side, 'INNER' join
//------------
//inner join
//v0v1 => v1v2 is inner angle for positive side
//and is outter angle of negative side
//inside joint share the same cutpoint
positiveSideVectors.Add(new Vector(cutPoint.x, cutPoint.y));
}
else if (angle_rad_diff < 0)
{
//'OBTUSE' angle side,'OUTTER' join
//-------------------
switch (LineJoinKind)
{
default: throw new NotSupportedException();
case LineJoin.Round:
ArcGenerator.GenerateArcNew(positiveSideVectors,
x1, y1,
delta_v0v1,
angle_rad_diff);
break;
case LineJoin.Miter:
{
//check mitter limit
double cal_mitterLen = HalfWidth / Math.Sin((Math.PI - angle_rad_diff) / 2);
double half_mitterLen = HalfWidth * MitterLimit;
if (cal_mitterLen > half_mitterLen)
{
Vector2 mid_bc = (vec_b + vec_c) / 2;
Vector2 vec_bc = vec_c - vec_b;
Vector2 limit_delta = vec_bc.RotateInDegree(90).NewLength(half_mitterLen);
Vector2 mid_bc_n = mid_bc + limit_delta;
Vector2 lim_cutPoint;
if (MyMath.FindCutPoint(
vec_a, vec_b, //a->b
mid_bc_n, mid_bc_n + vec_bc, //b->c
out lim_cutPoint))
{
positiveSideVectors.Add(new Vector(lim_cutPoint.x, lim_cutPoint.y));
}
else
{
}
if (MyMath.FindCutPoint(
vec_c, vec_d, //a->b
mid_bc_n, mid_bc_n + vec_bc, //b->c
out lim_cutPoint))
{
positiveSideVectors.Add(new Vector(lim_cutPoint.x, lim_cutPoint.y));
}
else
{
}
}
else
{
positiveSideVectors.Add(new Vector(cutPoint.x, cutPoint.y));
}
}
break;
}
}
else
{
//angle =0 , same line
}
}
else
{
//the 2 not cut
}
}
//----------------------------------------------------------------
if (negativeSideVectors != null)
{
delta_v0v1 = -delta_v0v1; //change vector direction***
delta_v1v2 = -delta_v1v2; //change vector direction***
Vector2 vec_a = new Vector2(x0 + delta_v0v1.x, y0 + delta_v0v1.y);
Vector2 vec_b = new Vector2(x1 + delta_v0v1.x, y1 + delta_v0v1.y);
Vector2 vec_c = new Vector2(x1 + delta_v1v2.x, y1 + delta_v1v2.y);
Vector2 vec_d = new Vector2(x2 + delta_v1v2.x, y2 + delta_v1v2.y);
//-------------
Vector2 cutPoint;
if (MyMath.FindCutPoint(
vec_a, vec_b, //a->b
vec_c, vec_d, //b->c
out cutPoint))
{
if (angle_rad_diff > 0)
{
//'ACUTE' angle side
//for negative side, this is outter join
//-------------------
switch (LineJoinKind)
{
case LineJoin.Round:
ArcGenerator.GenerateArcNew(negativeSideVectors,
x1, y1,
delta_v0v1,
angle_rad_diff);
break;
case LineJoin.Miter:
{
//see https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/stroke-miterlimit
double cal_mitterLen = HalfWidth / Math.Sin((Math.PI - angle_rad_diff) / 2);
double half_mitterLen = HalfWidth * MitterLimit;
if (cal_mitterLen > half_mitterLen)
{
Vector2 mid_bc = (vec_b + vec_c) / 2;
Vector2 vec_bc = vec_c - vec_b;
Vector2 limit_delta = vec_bc.RotateInDegree(-90).NewLength(half_mitterLen);
Vector2 mid_bc_n = mid_bc + limit_delta;
Vector2 lim_cutPoint;
if (MyMath.FindCutPoint(
vec_a, vec_b, //a->b
mid_bc_n, mid_bc_n + vec_bc, //b->c
out lim_cutPoint))
{
negativeSideVectors.Add(new Vector(lim_cutPoint.x, lim_cutPoint.y));
}
else
{
}
if (MyMath.FindCutPoint(
vec_c, vec_d, //a->b
mid_bc_n, mid_bc_n + vec_bc, //b->c
out lim_cutPoint))
{
negativeSideVectors.Add(new Vector(lim_cutPoint.x, lim_cutPoint.y));
}
else
{
}
}
else
{
negativeSideVectors.Add(new Vector(cutPoint.x, cutPoint.y));
}
}
break;
}
}
else if (angle_rad_diff < 0)
{
//'OBTUSE' angle side
//------------
//for negative side, this is outter join
//inner join share the same cutpoint
negativeSideVectors.Add(new Vector(cutPoint.x, cutPoint.y));
}
else
{
}
}
else
{
//the 2 not cut
}
}
}