Articolo
11/17/2011

Matrix Structure

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

Represents a 3x3 affine transformation matrix used for transformations in two-dimensional space.

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

Syntax

'Declaration
Public Structure Matrix _
    Implements IFormattable

public struct Matrix : IFormattable

<Matrix .../>

<object property="m11,m12,m21,m22,offsetX,offsetY"/>
- or -
<object property="m11 m12 m21 m22 offsetX offsetY"/>
-or-
<object property="Identity"/>

XAML Values

m11
The numeric value in the first row and first column of this Matrix. For more information, see M11.
m12
The numeric value in the first row and second column. For more information, see M12.
m21
The numeric value in the second row and first column. For more information, see M21.
m22
The numeric value in the second row and second column. For more information, see M22.
offsetX
The numeric value in the third row and first column. For more information, see OffsetX.
offsetY
The numeric value in the third row and second column. For more information, see OffsetY.
Identity
The literal Identity value. See Identity.

The Matrix type exposes the following members.

Constructors

	Name	Description
	Matrix	Initializes a Matrix structure.

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Properties

	Name	Description
	Identity	Gets an identity Matrix.
	IsIdentity	Gets a value that indicates whether this Matrix structure is an identity matrix.
	M11	Gets or sets the value of the first row and first column of this Matrix structure.
	M12	Gets or sets the value of the first row and second column of this Matrix structure.
	M21	Gets or sets the value of the second row and first column of this Matrix structure.
	M22	Gets or sets the value of the second row and second column of this Matrix structure.
	OffsetX	Gets or sets the value of the third row and first column of this Matrix structure.
	OffsetY	Gets or sets the value of the third row and second column of this Matrix structure.

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Methods

	Name	Description
	Equals(Matrix)	Determines whether the specified Matrix structure is identical to this instance.
	Equals(Object)	Determines whether the specified Object is a Matrix structure that is identical to this Matrix. (Overrides ValueType.Equals(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.)
	GetHashCode	Returns the hash code for this Matrix structure. (Overrides ValueType.GetHashCode().)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	ToString()	Creates a String representation of this Matrix structure. (Overrides ValueType.ToString().)
	ToString(IFormatProvider)	Creates a String representation of this Matrix structure with culture-specific formatting information.
	Transform	Transforms the specified point by the Matrix and returns the result.

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Operators

	Name	Description
	Equality	Determines whether the two specified Matrix structures are identical.
	Inequality	Determines whether the two specified Matrix structures are not identical.

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Explicit Interface Implementations

	Name	Description
	IFormattable.ToString	Infrastructure. For a description of this member, see ToString.

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Remarks

A 3x3 matrix is used for transformations in a two-dimensional x-y plane. Affine transformation matrices can be multiplied to form any number of linear transformations, such as rotation and skew (shear), followed by translation. An affine transformation matrix has its final column equal to (0, 0, 1), so only the members in the first two columns need to be specified. Note that vectors are expressed as row-vectors, not column vectors.

A Matrix is stored using row-major order and has the following structure:

M11	M12	0
M21	M22	0
OffsetX	OffsetY	1

The members in the last row, OffsetX and OffsetY, represent translation values.

In methods and properties, the transformation matrix is usually specified as a vector with only six members, as follows:

(M11, M12, M21, M22, OffsetX, OffsetY)

Although you can use a Matrix structure directly to translate individual points, or with a MatrixTransform to transform objects, Silverlight also provides a set of classes that enable you to transform objects without working directly with matrices: RotateTransform, ScaleTransform, SkewTransform, and TranslateTransform.

Properties of a Matrix are animatable (as one or more DoubleAnimation animations or DoubleAnimationUsingKeyFrames).

A Matrix provides the property value for the MatrixTransform.Matrix property.

Related types can be used for transformation matrices in three-dimensional space and then used for a projection. See Matrix3D and Matrix3DProjection.

In the XAML syntax, either a comma or space can be used as a delimiter.

Examples

The following XAML defines a Matrix that provides data for a MatrixTransform applied to a rectangular shape. In this case, the matrix combines an offset (OffsetX and OffsetY) and a skew (M12). Note that this same effect could have been produced by combining a TranslateTransform and a SkewTransform. Whether to use a single Matrix or combinations of discrete transforms is a matter of coding style, the results are identical.

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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