Matrix3x2F::Rotation method (d2d1helper.h)

Creates a rotation transformation that has the specified angle and center point.

Syntax

Matrix3x2F Rotation(
  FLOAT         angle,
  D2D1_POINT_2F center
);

Parameters

angle

Type: FLOAT

The rotation angle in degrees. A positive angle creates a clockwise rotation, and a negative angle creates a counterclockwise rotation.

center

Type: D2D1_POINT_2F

The point about which the rotation is performed.

Return value

Type: Matrix3x2F

The new rotation transformation.

Remarks

When calling this method, specify a centerPoint to rotate the object about, and the rotation angle in degrees. The following illustration shows a square rotated 45 degrees about its center point.

Examples

The following example uses the D2D1::Matrix3x2F::Rotation method to create a rotation matrix that rotates a square clockwise 45 degrees about the center of the square and passes the matrix to the SetTransform method of the render target (m_pRenderTarget).

The following illustration shows the effect of applying the preceding rotation transformation to the square. The original square is a dotted outline, and the rotated square is a solid outline.

    // Create a rectangle.
    D2D1_RECT_F rectangle = D2D1::Rect(438.0f, 301.5f, 498.0f, 361.5f);

    // Draw the rectangle.
    m_pRenderTarget->DrawRectangle(
        rectangle,
        m_pOriginalShapeBrush,
        1.0f,
        m_pStrokeStyleDash
        );

    // Apply the rotation transform to the render target.
    m_pRenderTarget->SetTransform(
        D2D1::Matrix3x2F::Rotation(
            45.0f,
            D2D1::Point2F(468.0f, 331.5f))
        );

    // Fill the rectangle.
    m_pRenderTarget->FillRectangle(rectangle, m_pFillBrush);

    // Draw the transformed rectangle.
    m_pRenderTarget->DrawRectangle(rectangle, m_pTransformedShapeBrush);

Code has been omitted from this example. For more information about transforms, see the Transforms Overview.

Requirements

See also

Matrix3x2F