IInkRenderer::MeasureStroke

4/8/2010

Calculates the rectangle on the device context that would contain a stroke if it were drawn with the IInkRenderer object using the IInkRenderer::DrawStroke method.

Syntax

HRESULT MeasureStroke (
  [in] IInkStrokeDisp *stroke,
  [in, optional, defaultvalue(0)] IInkDrawingAttributes 
    *drawingAttributes,
  [out, retval] IInkRectangle **Rectangle
);

Parameters

• stroke
  The stroke to measure.

• drawingAttributes
  The IInkDrawingAttributes to use when calculating the rectangle, which override the drawing attributes on the stroke. The default value is NULL, which means the stroke is measured by using its own drawing attributes.

• Rectangle
  Returns the rectangle on the device context that would contain the stroke if the stroke were drawn with the DrawStroke method of the IInkRenderer object. The stroke must contain x– and y–coordinates to calculate the rectangle. Otherwise, the method returns an empty rectangle.

Return Value

Remarks

This is accurate only if you pass the same arguments to both MeasureStroke and IInkRenderer::DrawStroke.

Since the bounding box is affected by the pen width, this width is scaled appropriately for the IInkRenderer's view transform. To do this, the pen width is multiplied by the square root of the determinant of the view transform. The height and width of the bounding box are expanded by half this amount in each direction, and the right and bottom sides are incremented by one.

For example, consider that the pen width is originally 53, the square root of the determinant of the view transform is 50, and the bounding box is (0, 0, 1000, 1000). The pen width adjustment to the bounding box in each direction is calculated as (53 * 50) / 2, and the right and bottom sides are incremented by one. This results in a rendered bounding box of (-1325, -1325, 2326, 2326).

Requirements

See Also

Concepts

Windows Mobile Ink Reference