57 lines
1.8 KiB
C#
57 lines
1.8 KiB
C#
using Graphing.Forms;
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using Graphing.Parts;
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namespace Graphing.Graphables;
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public class TangentLine : Graphable
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{
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public double Position { get; set; }
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protected readonly Equation parent;
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protected readonly EquationDelegate parentEqu;
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protected readonly double length;
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public TangentLine(double length, double position, Equation parent)
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{
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Name = $"Tangent Line of {parent.Name}";
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parentEqu = parent.GetDelegate();
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Position = position;
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this.length = length;
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this.parent = parent;
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}
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public override IEnumerable<IGraphPart> GetItemsToRender(in GraphForm graph)
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{
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Float2 point = new(Position, parentEqu(Position));
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return [MakeSlopeLine(point, DerivativeAtPoint(Position)),
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new GraphUiCircle(point, 8)];
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}
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protected GraphLine MakeSlopeLine(Float2 position, double slope)
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{
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double dirX = length, dirY = slope * length;
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double magnitude = Math.Sqrt(dirX * dirX + dirY * dirY);
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dirX /= magnitude * 2 / length;
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dirY /= magnitude * 2 / length;
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return new(new(position.x + dirX, position.y + dirY), new(position.x - dirX, position.y - dirY));
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}
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protected double DerivativeAtPoint(double x)
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{
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const double step = 1e-3;
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return (parentEqu(x + step) - parentEqu(x)) / step;
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}
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public override Graphable DeepCopy() => new TangentLine(length, Position, parent);
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public override void EraseCache() { }
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public override long GetCacheBytes() => 0;
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public override bool ShouldSelectGraphable(in GraphForm graph, Float2 graphMousePos, double factor) => false;
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public override Float2 GetSelectedPoint(in GraphForm graph, Float2 graphMousePos) => default;
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public override void Preload(Float2 xRange, Float2 yRange) { }
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}
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