Class Point2D

The Point2D class can represent a position in 2D space, or a vector in 2D space. Some operations assume that the interpretation is a vector.

Inheritance
object
Point2D
Inherited Members
Namespace: DesignData.SDS2.Primitives
Assembly: DesignData.SDS2.Primitives.dll
Syntax
public sealed class Point2D
Remarks

Note that intermediate arithmetic is done in floating point, and thus some operations may have intermediate results that overflow, underflow or experience cancellation error, like all floating-point arithmetic.

Constructors

Point2D()

Instantiates a point with X and Y set to zero

Declaration
public Point2D()
Remarks

Note that intermediate arithmetic is done in floating point, and thus some operations may have intermediate results that overflow, underflow or experience cancellation error, like all floating-point arithmetic.

Point2D(Point2D)

Instantiates a point equal to the given point

Declaration
public Point2D(Point2D pt)
Parameters
Type Name Description
Point2D pt

The point whose value to copy
Remarks

Note that intermediate arithmetic is done in floating point, and thus some operations may have intermediate results that overflow, underflow or experience cancellation error, like all floating-point arithmetic.

Point2D(Vector2D)

Instantiates a point with the X and Y values of the given vector

Declaration
public Point2D(Vector2D vector)
Parameters
Type Name Description
Vector2D vector

The point whose value to copy
Remarks

Note that intermediate arithmetic is done in floating point, and thus some operations may have intermediate results that overflow, underflow or experience cancellation error, like all floating-point arithmetic.

Point2D(double, double)

Instantiates a point with the given X and Y values

Declaration
public Point2D(double x, double y)
Parameters
Type Name Description
double x

The X value for the new point
double y

The Y value for the new point
Remarks

Note that intermediate arithmetic is done in floating point, and thus some operations may have intermediate results that overflow, underflow or experience cancellation error, like all floating-point arithmetic.

Properties

X

The X-coordinate of the point

Declaration
public double X { get; }
Property Value
Type Description
double
Remarks

Note that intermediate arithmetic is done in floating point, and thus some operations may have intermediate results that overflow, underflow or experience cancellation error, like all floating-point arithmetic.

Y

The Y-coordinate of the point

Declaration
public double Y { get; }
Property Value
Type Description
double
Remarks

Note that intermediate arithmetic is done in floating point, and thus some operations may have intermediate results that overflow, underflow or experience cancellation error, like all floating-point arithmetic.

Methods

BinEquals(Point2D, double)

Returns true if this point and the given point fall within the same "bin". A "bin" is a square region of space approximately binSize on a side.

Declaration
public bool BinEquals(Point2D other, double binSize)
Parameters
Type Name Description
Point2D other

The other point
double binSize

The size of a bin.
Returns
Type Description
bool
Remarks

Unlike EpsilonEquals, BinEquals maintains the transitive rule of equality, but some points which are arbitrarily close together in distance are unequal according got EpsilonEquals, because they fall into different bins.

EpsilonEquals(Point2D, double)

Returns true if the squared distance between this point and the given point is less than distance_squared.

Declaration
public bool EpsilonEquals(Point2D other, double distanceSquared)
Parameters
Type Name Description
Point2D other

The other point
double distanceSquared

The square of the smallest distance value that should be considered different
Returns
Type Description
bool
Remarks

Note that EpsilonEquals can violate the transitivity rule of equality comparison, because there are many groups of points (p, q, r) where p.EpsilonEquals(q) and p.EpsilonEquals(r) but not q.EpsilonEquals(r).

Equals(object)

Checks if each element of the points are equal using Double.Equals on each component. Note that this is an "exact" comparison method, and only appropriate in special circumstances.

Declaration
public override bool Equals(object obj)
Parameters
Type Name Description
object obj

The point to compare to
Returns
Type Description
bool
Overrides
Remarks

Note that intermediate arithmetic is done in floating point, and thus some operations may have intermediate results that overflow, underflow or experience cancellation error, like all floating-point arithmetic.

~Point2D()

The Point2D class can represent a position in 2D space, or a vector in 2D space. Some operations assume that the interpretation is a vector.

Declaration
protected ~Point2D()
Remarks

Note that intermediate arithmetic is done in floating point, and thus some operations may have intermediate results that overflow, underflow or experience cancellation error, like all floating-point arithmetic.

GetHashCode()

Returns the hash code for this instance. True for instances which are Equals(), otherwise False with high probability. Specific hash values are implementation-dependent.

Declaration
public override int GetHashCode()
Returns
Type Description
int
Overrides
Remarks

Note that intermediate arithmetic is done in floating point, and thus some operations may have intermediate results that overflow, underflow or experience cancellation error, like all floating-point arithmetic.

Interpolate(Point2D, double)

Performs linear interpolation between this point and the other

Declaration
public Point2D Interpolate(Point2D other, double t)
Parameters
Type Name Description
Point2D other

The other point
double t

Controls the mixing between the two points. This function is defined for all values of t, though strictly speaking only values in the interval [0,1] are interpolations, and other values are extrapolations.
Returns
Type Description
Point2D
Remarks

This is equal to this + (other - this) * t.

Note that due to floating point arithmetic, p.project(q, 1.0) may not be exactly equal to q.

ToString()

Formats the point into a string. Note that because the values are rounded for display, parsing them to retrieve the X and Y values will not necessarily yield the same point.

Declaration
public override string ToString()
Returns
Type Description
string
Overrides
Remarks

Note that intermediate arithmetic is done in floating point, and thus some operations may have intermediate results that overflow, underflow or experience cancellation error, like all floating-point arithmetic.

Operators

operator ==(Point2D, Point2D)

Checks if each element of the points are equal using == on each component. Note that this is an "exact" comparison method, and only appropriate in special circumstances.

Declaration
public static bool operator ==(Point2D p, Point2D q)
Parameters
Type Name Description
Point2D p

The point to compare
Point2D q

The point to compare to
Returns
Type Description
bool
Remarks

Note that intermediate arithmetic is done in floating point, and thus some operations may have intermediate results that overflow, underflow or experience cancellation error, like all floating-point arithmetic.

operator !=(Point2D, Point2D)

Checks if any element of the points are unequal using != on each component. Note that this is an "exact" comparison method, and only appropriate in special circumstances.

Declaration
public static bool operator !=(Point2D p, Point2D q)
Parameters
Type Name Description
Point2D p

The point to compare
Point2D q

The point to compare to
Returns
Type Description
bool
Remarks

Note that intermediate arithmetic is done in floating point, and thus some operations may have intermediate results that overflow, underflow or experience cancellation error, like all floating-point arithmetic.

operator -(Point2D, Point2D)

Return a vector which is the difference of the two given points

Declaration
public static Vector2D operator -(Point2D arg0, Point2D arg1)
Parameters
Type Name Description
Point2D arg0
Point2D arg1
Returns
Type Description
Vector2D
Remarks

Note that intermediate arithmetic is done in floating point, and thus some operations may have intermediate results that overflow, underflow or experience cancellation error, like all floating-point arithmetic.