IViewObjectEx::QueryHitRect

Indicates whether any point in a rectangle is within a given drawing aspect of an object.

HRESULT QueryHitRect(

DWORD dwAspect,	//Requested drawing aspect
LPRECT pRectBounds,	//Object bounding rectangle
LPRECT pRectLoc,	//Hit location
LONG lCloseHint,	//Suggested distance considered close
DWORD* pHitResult	//Pointer to returned hit information
);

Parameters

dwAspect

[in] Requested drawing aspect.

pRectBounds

[in] Object bounding rectangle in client coordinates of the containing window. This rectangle is computed and passed by the container so that the object can meaningfully interpret the hit location.

pRectLoc

[in] Hit test rectangle in specified in HIMETRIC units, relative to the top-left corner of the object.

lCloseHint

[in] Suggested distance in HIMETRIC units that the container considers close. This value is a hint, and objects can interpret it in their own way. Objects can also use this hint to roughly infer output resolution to choose expansiveness of hit test implementation.

pHitResult

[out] Pointer to returned information about the hit expressed as the HITRESULT enumeration values.

Return Values

S_OK

The hit information was successfully returned in pHitInfo.

E_FAIL

This method is not implemented for the requested aspect. Use DVASPECT_CONTENT instead.

Remarks

Containers may need to test whether an object overlaps a given drawing aspect of another object. They can determine whether the objects overlap by requesting a region or at least a bounding rectangle of the aspect in question. However, a quicker way to do this is to call IViewObjectEx::QueryHitRect to ask the object whether a given rectangle intersects one of its drawing aspects.

Note Unlike IViewObjectEx::QueryHitPoint, this method does not return HITRESULT_TRANSPARENT or HITRESULT_CLOSE. It is strictly hit or miss, returning HITRESULT_OUTSIDE if no point in the rectangle is hit and HITRESULT_HIT if at least one point in the rectangle is a hit.

Note to Implementers

An object supporting IViewObjectEx is required to implement this method at least for the DVASPECT_CONTENT aspect. The object should not take any other action in response to this method other than to return the information; there should be no side-effects. If there is any ambiguity about whether a point is a hit, for instance due to coordinates not converting exactly, the object should return HITRESULT_HIT whenever any point in the rectangle might be a hit on the object. That is, it is permissible to claim a hit for a point that is not actually rendered, but never correct to claim a miss for any point that is in the rendered image of the object.

See Also

HITRESULT