Article
11/18/2011

Matrix3DProjection Class

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Enables you to apply a Matrix3D to an object.

Inheritance Hierarchy

System.Object
  System.Windows.DependencyObject
    System.Windows.Media.Projection
      System.Windows.Media.Matrix3DProjection

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

Syntax

'Declaration
<ContentPropertyAttribute("ProjectionMatrix", True)> _
Public NotInheritable Class Matrix3DProjection _
    Inherits Projection

[ContentPropertyAttribute("ProjectionMatrix", true)]
public sealed class Matrix3DProjection : Projection

The Matrix3DProjection type exposes the following members.

Constructors

	Name	Description
	Matrix3DProjection	Initializes a new instance of a Matrix3DProjection class.

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Properties

	Name	Description
	Dispatcher	Gets the Dispatcher this object is associated with. (Inherited from DependencyObject.)
	ProjectionMatrix	Gets or sets the Matrix3D that is used for the projection that is applied to the object.

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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
	ProjectionMatrixProperty	Identifies the ProjectionMatrix dependency property.

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Remarks

Matrix3DProjection is a wrapper class around a Matrix3D.

You need to provide a three-dimensional (3-D) transform matrix that goes from object space (UIElement space) to homogeneous screen space, and the system implicitly does the perspective divide on resulting coordinates.

You can use the Matrix3DProjection and Matrix3D types for more complex semi–3-D scenarios than are possible with the PlaneProjection. Matrix3DProjection provides you with a complete 3-D transform matrix to apply to any UIElement so that you can apply arbitrary model transformation matrices and perspective matrices to Silverlight elements.

Because these APIs are minimal, if you use them, you need to write the code that correctly creates the 3-D transform matrices. Therefore, it is easier to use PlaneProjection for most 3-D scenarios. For more information about how to use PlaneProjection, see 3-D Effects (Perspective Transforms).

To use Matrix3DProjection, you need to use standard 3-D transformation matrices. For more information about how to construct and use these 3-D matrices, refer to the DirectX documentation. Functions of particular note to users of Matrix3DProjection are the standard translate, scale, rotate, and perspective matrices.

Examples

The following example uses a simple Matrix3D matrix to transform the image in the X and Y directions when you click the image.

Run this sample

<!-- When you click on the image, the projection is applied. -->
<Image MouseLeftButtonDown="ApplyProjection" x:Name="BeachImage" Source="guy_by_the_beach.jpg"
       Width="200"/>

private void ApplyProjection(Object sender, MouseButtonEventArgs e)
{
    Matrix3D m = new Matrix3D();

    // This matrix simply translates the image 100 pixels
    // down and 100 pixels right.
    m.M11 = 1.0; m.M12 = 0.0; m.M13 = 0.0; m.M14 = 0.0;
    m.M21 = 0.0; m.M22 = 1.0; m.M23 = 0.0; m.M24 = 0.0;
    m.M31 = 0.0; m.M32 = 0.0; m.M33 = 1.0; m.M34 = 0.0;
    m.OffsetX = 100; m.OffsetY = 100; m.OffsetZ = 0; m.M44 = 1.0;

    Matrix3DProjection m3dProjection = new Matrix3DProjection();
    m3dProjection.ProjectionMatrix = m;

    BeachImage.Projection = m3dProjection;

}

You can also apply a Matrix3DProjection to an object by using XAML. The following example shows how to apply the same transform as in the previous example but uses XAML instead of procedural code:

<Image Source="guy_by_the_beach.jpg">
    <Image.Projection>
        <Matrix3DProjection  ProjectionMatrix="2, 0, 0, 0,
                                              0, 2, 0, 0,
                                              0, 0, 1, 0,
                                              100, 100, 0, 1"/>
    </Image.Projection>
</Image>

You can multiply matrices together to create more complex effects. The following example uses several Matrix3D matrices that apply a 3-D transform to an image when you click the image.

Run this sample

<!-- When you click on the image, the projection is applied. -->
<Image MouseLeftButtonDown="ApplyProjection" x:Name="BeachImage" Source="guy_by_the_beach.jpg" 
       Width="200"/>

private void ApplyProjection(Object sender, MouseButtonEventArgs e)
{
    // Translate the image along the negative Z-axis such that it occupies 50% of the
    // vertical field of view.
    double fovY = Math.PI / 2.0;
    double translationZ = -BeachImage.ActualHeight / Math.Tan(fovY / 2.0);
    double theta = 20.0 * Math.PI / 180.0;

    // You can create a 3D effect by creating a number of simple 
    // tranformation Matrix3D matrixes and then multiply them together.
    Matrix3D centerImageAtOrigin = TranslationTransform(
             -BeachImage.ActualWidth / 2.0,
             -BeachImage.ActualHeight / 2.0, 0);
    Matrix3D invertYAxis = CreateScaleTransform(1.0, -1.0, 1.0);
    Matrix3D rotateAboutY = RotateYTransform(theta);
    Matrix3D translateAwayFromCamera = TranslationTransform(0, 0, translationZ);
    Matrix3D perspective = PerspectiveTransformFovRH(fovY,
            LayoutRoot.ActualWidth / LayoutRoot.ActualHeight,   // aspect ratio
            1.0,                                                // near plane
            1000.0);                                            // far plane
    Matrix3D viewport = ViewportTransform(LayoutRoot.ActualWidth, LayoutRoot.ActualHeight);

    Matrix3D m = centerImageAtOrigin * invertYAxis;
    m = m * rotateAboutY;
    m = m * translateAwayFromCamera;
    m = m * perspective;
    m = m * viewport;

    Matrix3DProjection m3dProjection = new Matrix3DProjection();
    m3dProjection.ProjectionMatrix = m;

    BeachImage.Projection = m3dProjection;
}

private Matrix3D TranslationTransform(double tx, double ty, double tz)
{
    Matrix3D m = new Matrix3D();

    m.M11 = 1.0; m.M12 = 0.0; m.M13 = 0.0; m.M14 = 0.0;
    m.M21 = 0.0; m.M22 = 1.0; m.M23 = 0.0; m.M24 = 0.0;
    m.M31 = 0.0; m.M32 = 0.0; m.M33 = 1.0; m.M34 = 0.0;
    m.OffsetX = tx; m.OffsetY = ty; m.OffsetZ = tz; m.M44 = 1.0;

    return m;
}

private Matrix3D CreateScaleTransform(double sx, double sy, double sz)
{
    Matrix3D m = new Matrix3D();

    m.M11 = sx; m.M12 = 0.0; m.M13 = 0.0; m.M14 = 0.0;
    m.M21 = 0.0; m.M22 = sy; m.M23 = 0.0; m.M24 = 0.0;
    m.M31 = 0.0; m.M32 = 0.0; m.M33 = sz; m.M34 = 0.0;
    m.OffsetX = 0.0; m.OffsetY = 0.0; m.OffsetZ = 0.0; m.M44 = 1.0;

    return m;
}

private Matrix3D RotateYTransform(double theta)
{
    double sin = Math.Sin(theta);
    double cos = Math.Cos(theta);

    Matrix3D m = new Matrix3D();

    m.M11 = cos; m.M12 = 0.0; m.M13 = -sin; m.M14 = 0.0;
    m.M21 = 0.0; m.M22 = 1.0; m.M23 = 0.0; m.M24 = 0.0;
    m.M31 = sin; m.M32 = 0.0; m.M33 = cos; m.M34 = 0.0;
    m.OffsetX = 0.0; m.OffsetY = 0.0; m.OffsetZ = 0.0; m.M44 = 1.0;

    return m;
}

private Matrix3D RotateZTransform(double theta)
{
    double cos = Math.Cos(theta);
    double sin = Math.Sin(theta);

    Matrix3D m = new Matrix3D();
    m.M11 = cos; m.M12 = sin; m.M13 = 0.0; m.M14 = 0.0;
    m.M21 = -sin; m.M22 = cos; m.M23 = 0.0; m.M24 = 0.0;
    m.M31 = 0.0; m.M32 = 0.0; m.M33 = 1.0; m.M34 = 0.0;
    m.OffsetX = 0.0; m.OffsetY = 0.0; m.OffsetZ = 0.0; m.M44 = 1.0;
    return m;
}

private Matrix3D PerspectiveTransformFovRH(double fieldOfViewY, double aspectRatio, double zNearPlane, double zFarPlane)
{
    double height = 1.0 / Math.Tan(fieldOfViewY / 2.0);
    double width = height / aspectRatio;
    double d = zNearPlane - zFarPlane;

    Matrix3D m = new Matrix3D();
    m.M11 = width; m.M12 = 0; m.M13 = 0; m.M14 = 0;
    m.M21 = 0; m.M22 = height; m.M23 = 0; m.M24 = 0;
    m.M31 = 0; m.M32 = 0; m.M33 = zFarPlane / d; m.M34 = -1;
    m.OffsetX = 0; m.OffsetY = 0; m.OffsetZ = zNearPlane * zFarPlane / d; m.M44 = 0;

    return m;
}

private Matrix3D ViewportTransform(double width, double height)
{
    Matrix3D m = new Matrix3D();

    m.M11 = width / 2.0; m.M12 = 0.0; m.M13 = 0.0; m.M14 = 0.0;
    m.M21 = 0.0; m.M22 = -height / 2.0; m.M23 = 0.0; m.M24 = 0.0;
    m.M31 = 0.0; m.M32 = 0.0; m.M33 = 1.0; m.M34 = 0.0;
    m.OffsetX = width / 2.0; m.OffsetY = height / 2.0; m.OffsetZ = 0.0; m.M44 = 1.0;

    return m;
}

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.