CircleArc.cs

using System;
using System.Threading.Tasks;
using System.Xml;
using SkiaSharp;
using Waher.Layout.Layout2D.Model.Attributes;
 
namespace Waher.Layout.Layout2D.Model.Figures
{
    public class CircleArc : FigurePoint
    {
        private LengthAttribute radius;
        private FloatAttribute startDegrees;
        private FloatAttribute endDegrees;
        private FloatAttribute spanDegrees;
        private BooleanAttribute clockwise;
        private BooleanAttribute center;
        private float r;
        private float start;
        private float end;
        private float span;
        private bool clockDir;
        private bool includeCenter;
 
        public CircleArc(Layout2DDocument Document, ILayoutElement Parent)
            : base(Document, Parent)
        {
        }
 
        public override string LocalName => "CircleArc";
 
        public LengthAttribute RadiusAttribute
        {
            get => this.radius;
            set => this.radius = value;
        }
 
        public FloatAttribute StartDegreesAttribute
        {
            get => this.startDegrees;
            set => this.startDegrees = value;
        }
 
        public FloatAttribute EndDegreesAttribute
        {
            get => this.endDegrees;
            set => this.endDegrees = value;
        }
 
        public FloatAttribute SpanDegreesAttribute
        {
            get => this.spanDegrees;
            set => this.spanDegrees = value;
        }
 
        public BooleanAttribute ClockwiseAttribute
        {
            get => this.clockwise;
            set => this.clockwise = value;
        }
 
        public BooleanAttribute CenterAttribute
        {
            get => this.center;
            set => this.center = value;
        }
 
        public override Task FromXml(XmlElement Input)
        {
            this.radius = new LengthAttribute(Input, "radius", this.Document);
            this.startDegrees = new FloatAttribute(Input, "startDegrees", this.Document);
            this.endDegrees = new FloatAttribute(Input, "endDegrees", this.Document);
            this.spanDegrees = new FloatAttribute(Input, "spanDegrees", this.Document);
            this.clockwise = new BooleanAttribute(Input, "clockwise", this.Document);
            this.center = new BooleanAttribute(Input, "center", this.Document);
 
            return base.FromXml(Input);
        }
 
        public override void ExportAttributes(XmlWriter Output)
        {
            base.ExportAttributes(Output);
 
            this.radius?.Export(Output);
            this.startDegrees?.Export(Output);
            this.endDegrees?.Export(Output);
            this.spanDegrees?.Export(Output);
            this.clockwise?.Export(Output);
            this.center?.Export(Output);
        }
 
        public override ILayoutElement Create(Layout2DDocument Document, ILayoutElement Parent)
        {
            return new CircleArc(Document, Parent);
        }
 
        public override void CopyContents(ILayoutElement Destination)
        {
            base.CopyContents(Destination);
 
            if (Destination is CircleArc Dest)
            {
                Dest.radius = this.radius?.CopyIfNotPreset(Destination.Document);
                Dest.startDegrees = this.startDegrees?.CopyIfNotPreset(Destination.Document);
                Dest.endDegrees = this.endDegrees?.CopyIfNotPreset(Destination.Document);
                Dest.spanDegrees = this.spanDegrees?.CopyIfNotPreset(Destination.Document);
                Dest.clockwise = this.clockwise?.CopyIfNotPreset(Destination.Document);
                Dest.center = this.center?.CopyIfNotPreset(Destination.Document);
            }
        }
 
        public override async Task DoMeasureDimensions(DrawingState State)
        {
            await base.DoMeasureDimensions(State);
 
            EvaluationResult<Length> RadiusLength = await this.radius.TryEvaluate(State.Session);
            if (RadiusLength.Ok)
                State.CalcDrawingSize(RadiusLength.Result, ref this.r, true, this);
            else
                this.defined = false;
 
            this.clockDir = await this.clockwise.Evaluate(State.Session, true);
            this.includeCenter = await this.center.Evaluate(State.Session, false);
 
            EvaluationResult<float> Degrees = await this.startDegrees.TryEvaluate(State.Session);
            if (Degrees.Ok)
                this.start = (float)Math.IEEERemainder(Degrees.Result, 360);
            else
                this.defined = false;
 
            Degrees = await this.endDegrees.TryEvaluate(State.Session);
            if (Degrees.Ok)
            {
                this.end = (float)Math.IEEERemainder(Degrees.Result, 360);
 
                if (this.clockDir)
                    this.span = this.end - this.start;
                else
                    this.span = this.start - this.end;
 
                if (this.span < 0)
                    this.span += 360;
            }
            else
            {
                Degrees = await this.spanDegrees.TryEvaluate(State.Session);
                if (Degrees.Ok)
                {
                    this.span = Degrees.Result;
                    if (this.clockDir)
                        this.end = this.start + this.span;
                    else
                        this.end = this.start - this.span;
 
                    this.end = (float)Math.IEEERemainder(this.end, 360);
                }
                else
                    this.defined = false;
            }
 
            if (this.defined)
            {
                if (this.span >= 360)
                {
                    this.IncludePoint(this.xCoordinate - this.r, this.yCoordinate);
                    this.IncludePoint(this.xCoordinate + this.r, this.yCoordinate);
                    this.IncludePoint(this.xCoordinate, this.yCoordinate - this.r);
                    this.IncludePoint(this.xCoordinate, this.yCoordinate + this.r);
                }
                else
                {
                    float a = this.start;
                    float r = (float)Math.IEEERemainder(this.start, 90);
                    bool First = true;
 
                    this.IncludePoint(this.xCoordinate, this.yCoordinate, this.r, this.r, this.start);
 
                    if (this.clockDir)
                    {
                        if (this.end < this.start)
                            this.end += 360;
 
                        while (a < this.end)
                        {
                            if (First)
                            {
                                a += 90 - r;
                                First = false;
                            }
                            else
                                a += 90;
 
                            this.IncludePoint(this.xCoordinate, this.yCoordinate, this.r, this.r, a);
                        }
                    }
                    else
                    {
                        if (this.end > this.start)
                            this.end -= 360;
 
                        while (a > this.end)
                        {
                            if (First)
                            {
                                a -= r;
                                First = false;
                            }
                            else
                                a -= 90;
 
                            this.IncludePoint(this.xCoordinate, this.yCoordinate, this.r, this.r, a);
                        }
                    }
 
                    if (this.start != this.end)
                        this.IncludePoint(this.xCoordinate, this.yCoordinate, this.r, this.r, this.end);
 
                    if (this.includeCenter)
                        this.IncludePoint(this.xCoordinate, this.yCoordinate);
                }
            }
        }
 
        public override async Task Draw(DrawingState State)
        {
            if (this.defined)
            {
                if (this.span >= 360)
                {
                    SKPaint Fill = await this.TryGetFill(State);
                    if (!(Fill is null))
                        State.Canvas.DrawCircle(this.xCoordinate, this.yCoordinate, this.r, Fill);
 
                    SKPaint Pen = await this.TryGetPen(State);
                    if (!(Pen is null))
                        State.Canvas.DrawCircle(this.xCoordinate, this.yCoordinate, this.r, Pen);
                }
                else
                {
                    float Sweep = this.clockDir ? this.span : -this.span;
                    SKRect Oval = new SKRect(
                        this.xCoordinate - this.r, this.yCoordinate - this.r,
                        this.xCoordinate + this.r, this.yCoordinate + this.r);
 
                    this.start = (float)Math.IEEERemainder(this.start, 360);
                    if (this.start < 0)
                        this.start += 360;
 
                    this.end = (float)Math.IEEERemainder(this.end, 360);
                    if (this.end < 0)
                        this.end += 360;
 
                    SKPaint Fill = await this.TryGetFill(State);
                    if (!(Fill is null))
                        State.Canvas.DrawArc(Oval, this.start, Sweep, this.includeCenter, Fill);
 
                    SKPaint Pen = await this.TryGetPen(State);
                    if (!(Pen is null))
                        State.Canvas.DrawArc(Oval, this.start, Sweep, this.includeCenter, Pen);
                }
            }
        
            await base.Draw(State);
        }
 
        public override void ExportStateAttributes(XmlWriter Output)
        {
            base.ExportStateAttributes(Output);
 
            this.radius?.ExportState(Output);
            this.startDegrees?.ExportState(Output);
            this.endDegrees?.ExportState(Output);
            this.spanDegrees?.ExportState(Output);
            this.clockwise?.ExportState(Output);
            this.center?.ExportState(Output);
        }
 
    }
}