Articolo
11/17/2011

ArcSegment Class

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Represents an elliptical arc between two points.

Inheritance Hierarchy

System.Object
  System.Windows.DependencyObject
    System.Windows.Media.PathSegment
      System.Windows.Media.ArcSegment

Namespace: System.Windows.Media
Assembly: System.Windows (in System.Windows.dll)

Syntax

'Declaration
Public NotInheritable Class ArcSegment _
    Inherits PathSegment

public sealed class ArcSegment : PathSegment

<ArcSegment .../>

The ArcSegment type exposes the following members.

Constructors

	Name	Description
	ArcSegment	Initializes a new instance of the ArcSegment class.

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Properties

	Name	Description
	Dispatcher	Gets the Dispatcher this object is associated with. (Inherited from DependencyObject.)
	IsLargeArc	Gets or sets a value that indicates whether the arc should be greater than 180 degrees.
	Point	Gets or sets the endpoint of the elliptical arc.
	RotationAngle	Gets or sets the amount (in degrees) by which the ellipse is rotated about the x-axis.
	Size	Gets or sets the x- and y-radius of the arc as a Size structure.
	SweepDirection	Gets or sets a value that specifies whether the arc is drawn in the Clockwise or Counterclockwise direction.

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Methods

	Name	Description
	CheckAccess	Determines whether the calling thread has access to this object. (Inherited from DependencyObject.)
	ClearValue	Clears the local value of a dependency property. (Inherited from DependencyObject.)
	Equals(Object)	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
	GetAnimationBaseValue	Returns any base value established for a Silverlight dependency property, which would apply in cases where an animation is not active. (Inherited from DependencyObject.)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	GetValue	Returns the current effective value of a dependency property from a DependencyObject. (Inherited from DependencyObject.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	ReadLocalValue	Returns the local value of a dependency property, if a local value is set. (Inherited from DependencyObject.)
	SetValue	Sets the local value of a dependency property on a DependencyObject. (Inherited from DependencyObject.)
	ToString	Returns a string that represents the current object. (Inherited from Object.)

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Fields

	Name	Description
	IsLargeArcProperty	Identifies the IsLargeArc dependency property.
	PointProperty	Identifies the Point dependency property.
	RotationAngleProperty	Identifies the RotationAngle dependency property.
	SizeProperty	Identifies the Size dependency property.
	SweepDirectionProperty	Identifies the SweepDirection dependency property.

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Remarks

Use a PathFigure object to store ArcSegment objects and other segments.

An elliptical arc is defined by its start and end points, x- and y-radius, x-axis rotation factor, a value indicating whether the arc should be greater than 180 degrees, and a value describing the direction in which the arc is drawn. The ArcSegment class does not contain a property for the starting point of the arc; it only defines the destination point of the arc it represents. The beginning point of the arc is the current point of the PathFigure to which the ArcSegment is added.

The following illustrations demonstrate the different end point, Size, and RotationAngle settings.

ArcSegments with different Point settings ArcSegments with different Size settings ArcSegments with different RotationAngle settings

IsLargeArc and SweepDirection

For most arcs of a particular position, size, and rotation, there are four different arcs that can be drawn; the IsLargeArc and SweepDirection properties indicate which arc to use.

Of the four candidate arc sweeps, two represent large arcs with sweeps of 180 degrees or greater, and two represent smaller arcs with sweeps 180 degrees or less. If IsLargeArc is true, then one of the two larger arc sweeps is chosen; otherwise, if IsLargeArc is false, one of the smaller arc sweeps is chosen. The remaining two arc candidates are each drawn in a different direction: Counterclockwise or Clockwise. The SweepDirection property specifies which one to use.

The following illustrations show different IsLargeArc and SweepDirection settings.

ArcSegment objects with different IsLargeArc settings

ArcSegments with different IsLargeArc settings

ArcSegment objects with different SweepDirection settings

ArcSegments with different SweepDirection settings

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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