OleDraw
The OleDraw
helper function can be used to draw objects more easily. You can use it instead
of calling IViewObject::Draw
directly.
WINOLEAPI OleDraw(
|
IUnknown *
pUnk, |
//Pointer to the view object to be drawn |
|
DWORD dwAspect, |
//How the object is to be represented |
|
HDC hdcDraw, |
//Device context on which to draw |
|
LPCRECT lprcBounds |
//Pointer to the rectangle in which the object is
drawn |
|
); |
|
Parameters
pUnk
[in] Pointer
to the IUnknown interface on the view object that is to be drawn.
dwAspect
[in] How the
object is to be represented. Representations include content, an icon, a
thumbnail, or a printed document. Valid values are taken from the enumeration DVASPECT. See DVASPECT for
more information.
hdcDraw
[in] Device
context on which to draw. Cannot be a metafile device context.
lprcBounds
[in] Pointer
to a RECT structure specifying the rectangle in which the object should
be drawn. This parameter is converted to a RECTL structure and passed to
IViewObject::Draw.
Return Values
This function
supports the standard return values E_INVALIDARG and E_OUTOFMEMORY, as well as
the following:
S_OK
Object was
successfully drawn.
OLE_E_BLANK
No data to
draw from.
E_ABORT
The draw operation
was aborted.
VIEW_E_DRAW
An error
occurred in drawing.
OLE_E_INVALIDRECT
The rectangle
is invalid.
DV_E_NOIVIEWOBJECT
The object
doesn't support the IViewObject interface.
Remarks
The OleDraw
helper function calls the QueryInterface method for the object specified
(pUnk), asking for an IViewObject interface on that object. Then,
OleDraw converts the RECT structure to a RECTL structure,
and calls IViewObject::Draw
as follows:
lpViewObj->Draw(dwAspect,-1,0,0,0,hdcDraw,&rectl,0,0,0);
Do not use OleDraw
to draw into a metafile because it does not specify the lprcWBounds
parameter required for drawing into metafiles.
See Also