PathGradientBrush::RotateTransform method (gdipluspath.h)

The PathGradientBrush::RotateTransform method updates this brush's current transformation matrix with the product of itself and a rotation matrix.

Syntax

Status RotateTransform(
  [in] REAL        angle,
  [in] MatrixOrder order
);

Parameters

[in] angle

Type: REAL

Real number that specifies the angle of rotation in degrees.

[in] order

Type: MatrixOrder

Optional. Element of the MatrixOrder enumeration that specifies the order of the multiplication. MatrixOrderPrepend specifies that the rotation matrix is on the left, and MatrixOrderAppend specifies that the rotation matrix is on the right. The default value is MatrixOrderPrepend.

Return value

Type: Status

If the method succeeds, it returns Ok, which is an element of the Status enumeration.

If the method fails, it returns one of the other elements of the Status enumeration.

Remarks

A single 3 ×3 matrix can store any sequence of affine transformations. If you have several 3 ×3 matrices, each of which represents an affine transformation, the product of those matrices is a single 3 ×3 matrix that represents the entire sequence of transformations. The transformation represented by that product is called a composite transformation. For example, suppose matrix T represents a translation and matrix R represents a rotation. If matrix M is the product TR, then matrix M represents a composite transformation: first translate, then rotate.

Examples

The following example creates a PathGradientBrush object based on a triangular path. The calls to the PathGradientBrush::ScaleTransform and PathGradientBrush::RotateTransform methods of the PathGradientBrush object set the elements of the brush's transformation matrix so that it represents a composite transformation: first scale, then rotate. The code uses the path gradient brush twice to paint a rectangle: once before the transformation is set and once after the transformation is set.

VOID Example_RotateTransform(HDC hdc)
{
   Graphics graphics(hdc);

   // Create a path gradient brush based on an array of points.
   Point pts[] = {Point(0, 0), Point(50, 0), Point(50, 50)};
   PathGradientBrush pthGrBrush(pts, 3);

   // Fill an area with the path gradient brush (no transformation).
   graphics.FillRectangle(&pthGrBrush, 0, 0, 500, 500);

   pthGrBrush.ScaleTransform(3.0f, 1.0f);                 // first scale
   pthGrBrush.RotateTransform(60.0f, MatrixOrderAppend);  // then rotate

   // Fill the same area with the transformed path gradient brush.
   graphics.FillRectangle(&pthGrBrush, 0, 0, 500, 500);
}

Requirements

See also

Brushes and Filled Shapes

Creating a Path Gradient

Filling a Shape with a Color Gradient

Matrix

Matrix Representation of Transformations

MatrixOrder

PathGradientBrush

PathGradientBrush::GetTransform

PathGradientBrush::MultiplyTransform

PathGradientBrush::ResetTransform

PathGradientBrush::ScaleTransform

PathGradientBrush::SetTransform

PathGradientBrush::TranslateTransform

Transformations