private Ellipse ReadEllipse(ref CodeValuePair code)
{
var ellipse = new Ellipse();
Vector3f center = Vector3f.Zero;
Vector3f axisPoint = Vector3f.Zero;
Vector3f normal = Vector3f.UnitZ;
float ratio = 0;
Dictionary<ApplicationRegistry, XData> xData = new Dictionary<ApplicationRegistry, XData>();
code = this.ReadCodePair();
while (code.Code != 0)
{
switch (code.Code)
{
case 5:
ellipse.Handle = code.Value;
code = this.ReadCodePair();
break;
case 8: //layer code
ellipse.Layer = this.GetLayer(code.Value);
code = this.ReadCodePair();
break;
case 62: //aci color code
ellipse.Color = new AciColor(short.Parse(code.Value));
code = this.ReadCodePair();
break;
case 6: //type line code
ellipse.LineType = this.GetLineType(code.Value);
code = this.ReadCodePair();
break;
case 10:
center.X = float.Parse(code.Value);
code = this.ReadCodePair();
break;
case 20:
center.Y = float.Parse(code.Value);
code = this.ReadCodePair();
break;
case 30:
center.Z = float.Parse(code.Value);
code = this.ReadCodePair();
break;
case 11:
axisPoint.X = float.Parse(code.Value);
code = this.ReadCodePair();
break;
case 21:
axisPoint.Y = float.Parse(code.Value);
code = this.ReadCodePair();
break;
case 31:
axisPoint.Z = float.Parse(code.Value);
code = this.ReadCodePair();
break;
case 40:
ratio = float.Parse(code.Value);
code = this.ReadCodePair();
break;
case 41:
ellipse.StartAngle = (float) (double.Parse(code.Value)*MathHelper.RadToDeg);
code = this.ReadCodePair();
break;
case 42:
ellipse.EndAngle = (float) (double.Parse(code.Value)*MathHelper.RadToDeg);
code = this.ReadCodePair();
break;
case 210:
normal.X = float.Parse(code.Value);
code = this.ReadCodePair();
break;
case 220:
normal.Y = float.Parse(code.Value);
code = this.ReadCodePair();
break;
case 230:
normal.Z = float.Parse(code.Value);
code = this.ReadCodePair();
break;
case 1001:
XData xDataItem = this.ReadXDataRecord(code.Value, ref code);
xData.Add(xDataItem.ApplicationRegistry, xDataItem);
break;
default:
if (code.Code >= 1000 && code.Code <= 1071)
throw new DxfInvalidCodeValueEntityException(code.Code, code.Value, this.file,
"The extended data of an entity must start with the application registry code " + this.fileLine);
code = this.ReadCodePair();
break;
}
}
Vector3d ocsAxisPoint = MathHelper.Transform((Vector3d) axisPoint,
(Vector3d) normal,
MathHelper.CoordinateSystem.World,
MathHelper.CoordinateSystem.Object);
double rotation = (float) Vector2d.AngleBetween(Vector2d.UnitX, new Vector2d(ocsAxisPoint.X, ocsAxisPoint.Y));
ellipse.MajorAxis = 2*axisPoint.Modulus();
ellipse.MinorAxis = ellipse.MajorAxis*ratio;
ellipse.Rotation = (float) (rotation*MathHelper.RadToDeg);
ellipse.Center = center;
ellipse.Normal = normal;
ellipse.XData = xData;
return ellipse;
}
private void WriteEllipseAsPolyline(Ellipse ellipse)
{
//we will draw the ellipse as a polyline, it is not supported in AutoCad12 dxf files
this.WriteCodePair(0, DxfObjectCode.Polyline);
this.WriteEntityCommonCodes(ellipse);
//closed polyline
this.WriteCodePair(70, 1);
//dummy point
this.WriteCodePair(10, 0.0f);
this.WriteCodePair(20, 0.0f);
this.WriteCodePair(30, ellipse.Center.Z);
this.WriteCodePair(39, ellipse.Thickness);
this.WriteCodePair(210, ellipse.Normal.X);
this.WriteCodePair(220, ellipse.Normal.Y);
this.WriteCodePair(230, ellipse.Normal.Z);
//Obsolete; formerly an “entities follow flag” (optional; ignore if present)
//but its needed to load the dxf file in AutoCAD
this.WriteCodePair(66, "1");
this.WriteXData(ellipse.XData);
List<Vector2f> points = ellipse.PolygonalVertexes(ellipse.CurvePoints);
foreach (Vector2f v in points)
{
this.WriteCodePair(0, DxfObjectCode.Vertex);
this.WriteCodePair(8, ellipse.Layer);
this.WriteCodePair(70, 0);
this.WriteCodePair(10, v.X);
this.WriteCodePair(20, v.Y);
}
this.WriteCodePair(0, StringCode.EndSequence);
}
private static void Ellipse()
{
DxfDocument dxf = new DxfDocument();
Line line = new Line(new Vector3f(0, 0, 0), new Vector3f((float)(2 * Math.Cos(Math.PI / 4)), (float)(2 * Math.Cos(Math.PI / 4)), 0));
dxf.AddEntity(line);
Line line2 = new Line(new Vector3f(0, 0, 0), new Vector3f(0, -2, 0));
dxf.AddEntity(line2);
Arc arc=new Arc(Vector3f.Zero,2,45,270);
dxf.AddEntity(arc);
// ellipses are saved as polylines
Ellipse ellipse = new Ellipse(new Vector3f(2,2,0), 5,3);
ellipse.Rotation = 30;
ellipse.Normal=new Vector3f(1,1,1);
ellipse.Thickness = 2;
dxf.AddEntity(ellipse);
dxf.Save("ellipse.dxf", DxfVersion.AutoCad2000);
dxf = new DxfDocument();
dxf.Load("ellipse.dxf");
}
private void WriteEllipse(Ellipse ellipse)
{
if (this.activeSection != StringCode.EntitiesSection && !this.isBlockEntities)
{
throw new InvalidDxfSectionException(this.activeSection, this.file);
}
if (this.version == DxfVersion.AutoCad12)
{
this.WriteEllipseAsPolyline(ellipse);
return;
}
this.WriteCodePair(0, ellipse.CodeName);
this.WriteCodePair(5, ellipse.Handle);
this.WriteCodePair(100, SubclassMarker.Entity);
this.WriteEntityCommonCodes(ellipse);
this.WriteCodePair(100, SubclassMarker.Ellipse);
this.WriteCodePair(10, ellipse.Center.X);
this.WriteCodePair(20, ellipse.Center.Y);
this.WriteCodePair(30, ellipse.Center.Z);
float sine = (float) (0.5*ellipse.MajorAxis*Math.Sin(ellipse.Rotation*MathHelper.DegToRad));
float cosine = (float) (0.5*ellipse.MajorAxis*Math.Cos(ellipse.Rotation*MathHelper.DegToRad));
Vector3d axisPoint = MathHelper.Transform((Vector3d) new Vector3f(cosine, sine, 0),
(Vector3d) ellipse.Normal,
MathHelper.CoordinateSystem.Object,
MathHelper.CoordinateSystem.World);
this.WriteCodePair(11, axisPoint.X);
this.WriteCodePair(21, axisPoint.Y);
this.WriteCodePair(31, axisPoint.Z);
this.WriteCodePair(210, ellipse.Normal.X);
this.WriteCodePair(220, ellipse.Normal.Y);
this.WriteCodePair(230, ellipse.Normal.Z);
this.WriteCodePair(40, ellipse.MinorAxis/ellipse.MajorAxis);
this.WriteCodePair(41, ellipse.StartAngle*MathHelper.DegToRad);
this.WriteCodePair(42, ellipse.EndAngle*MathHelper.DegToRad);
this.WriteXData(ellipse.XData);
}