IInkDisp::HitTestCircle method (msinkaut.h)

Article
10/13/2021

Retrieves the InkStrokes collection that are either completely inside or intersected by a known circle.

Syntax

HRESULT HitTestCircle(
  [in]          long        X,
  [in]          long        Y,
  [in]          float       radius,
  [out, retval] IInkStrokes **Strokes
);

Parameters

[in] X

The x-position of the center of the hit test circle in ink space units.

[in] Y

The y-position of the center of the hit test circle in ink space units.

[in] radius

The radius of the circle to use in the hit test, in ink space units.

[out, retval] Strokes

When this method returns, contains the collection of strokes that are either completely inside or intersected by the specified circle.

Return value

This method can return one of these values.

Return code	Description
S_OK	Success.
E_POINTER	A parameter contained an invalid pointer.
E_INK_EXCEPTION	An exception occurred inside the method.
E_INVALIDARG	Invalid display handle.
E_UNEXPECTED	Unexpected parameter or property type.

Remarks

If a stroke intersects the circle, the complete stroke is returned.

The method computes the intersection, considering the full set of drawing attributes that apply to the stroke, including the full pen width, Bezier smoothing (if present), and shape of the pen tip.

After a rotation or shear transform has been performed on a stroke or a collection of strokes, the transformed x- and y- coordinates are no longer concentric with the original coordinates. Because of this, the radius argument should not be calculated from the x- or y- coordinates.

To determine which points of a known stroke intersect the test area, call the HitTest method of the IInkStrokeDisp object.

The application must always pass in a destination pointer for the resulting collection of strokes. If there are no intersections, the collection has a count of zero.

Requirements

Requirement	Value
Minimum supported client	Windows XP Tablet PC Edition [desktop apps only]
Minimum supported server	None supported
Target Platform	Windows
Header	msinkaut.h
Library	InkObj.dll