IViewObjectEx::GetNaturalExtent
Provides
sizing hints from the container for the object to use as the user resizes it.
HRESULT GetNaturalExtent(
|
DWORD dwAspect,
|
//Requested
drawing aspect |
|
LONG lindex,
|
//Portion of
object for draw operation |
|
DVTARGETDEVICE* ptd, |
//Pointer to
structure describing target device |
|
HDC hicTargetDev, |
//Information
context for ptd |
|
DVEXTENTINFO* pExtentInfo, |
//Structure
specifying sizing data |
|
LPSIZEL* pSizel,
|
//Pointer to
sizing data returned by object |
|
); |
|
Parameters
dwAspect
[in]
Requested drawing aspect. It can be any of the values from the DVASPECT enumeration.
lindex
[in]
Indicates the portion of the object that is of interest for the draw operation.
Its interpretation varies depending on the value in the dwAspect parameter.
See the DVASPECT
enumeration for more information.
ptd
[in] Pointer
to the target device structure that describes the device for which the object
is to be rendered. If NULL, the view should be rendered for the default target
device (typically the display). A value other than NULL is interpreted in
conjunction with hicTargetDev and hdcDraw. For example, if hdcDraw
specifies a printer as the device context, the ptd parameter points to a
structure describing that printer device. The data may actually be printed if hicTargetDev
is a valid value or it may be displayed in print preview mode if hicTargetDev
is NULL.
hicTargetDev
[in]
Specifies the information context for the target device indicated by the ptd
parameter from which the object can extract device metrics and test the
device's capabilities. If ptd is NULL; the object should ignore the
value in the hicTargetDev parameter.
pExtentInfo
[in] Pointer
to DVEXTENTINFO
structure that specifies the sizing data.
pSizel
[out] Pointer
to sizing data returned by the object. The returned sizing data is set to -1
for any dimension that was not adjusted. That is if cx is -1 then the
width was not adjusted, if cy is -1 then the height was not adjusted. If
E_FAIL is returned indicating no size was adjusted then psizel may be NULL.
Return Values
S_OK
The sizing
hints were successfully returned.
E_FAIL
This method
is not implemented for the specified dwAspect, or the size was not
adjusted.
E_NOTIMPL
This method
was not implemented.
Remarks
There are two
general approaches to sizing a control. The first approach gives the control
responsibility for sizing itself; the second approach gives the container
responsibility for sizing the control. The first approach is called autosizing.
There are two alternatives involved in the second approach: content sizing and
integral sizing.
The IViewObjectEx::GetNaturalExtent
method supports both content and integral sizing. In content sizing, the
container passes the DVEXTENTINFO structure to the object into which the object
returns a suggested size. In integral sizing, the container passes a preferred
size to the object in DVEXTENTINFO, and the object actually adjusts its
height. Integral sizing is used when the user rubberbands a new size in design
mode.
Autosizing
typically occurs with objects such as the Label control which resizes if the
autosize property was enabled and the associated text changed. Autosizing is
handled differently depending on the state of the object.
If the object
is inactive, the following occurs:
1. The object calls IOleClientSite::RequestNewObjectLayout.
2. The container calls IOleObject::GetExtent and retrieves the new
extents
3. The container calls IOleObject::SetExtent and adjusts the new
extents.
If the object
is active, the following occurs:
1. The object calls IOleInPlaceSite::OnPosRectChange to specify that it
requires resizing.
2. The container calls IOleInPlaceObject::SetObjectRects and specifies the new size.
The values of
the dwAspect parameter can be one of the following DVASPECT enumeration values:
DVASPECT_CONTENT
Provide a
representation of the control so it can be displayed as an embedded object
inside of a container. This value is typically specified for compound document
objects. The presentation can be provided for the screen or printer.
DVASPECT_DOCPRINT
Provide a
representation of the control on the screen as though it were printed to a
printer using the Print command from the File menu. The described data may
represent a sequence of pages..
DVASPECT_ICON
Provide an
iconic representation of the control.
DVASPECT_THUMBNAIL
Provide a
thumbnail representation of an object so it can be displayed in a browsing
tool. The thumbnail is approximately a 120 by 120 pixel, 16-color (recommended)
device-independent bitmap potentially wrapped in a metafile.
See Also