OleDraw
A version of this page is also available for
4/8/2010
This helper function provides a convenient way to draw objects by encapsulating the IViewObject::Draw method and other related maintenance functions for the drawing rectangle.
Syntax
WINOLEAPIOleDraw(
IUnknown* pUnk,
DWORD dwAspect,
HDC hdcDraw,
LPCRECT lprcBounds
);
Parameters
- pUnk
[in] Pointer to the IUnknown interface on the view object that is to be drawn.
dwAspect
[in] Specifies how the object is to be represented.Representations include the following:
- Content
- An icon
- A thumbnail
- A printed document
Valid values are taken from the enumeration DVASPECT. For more information, see DVASPECT.
hdcDraw
[in] Handle to the device context (DC) on which to draw.Cannot be a metafile device context.
lprcBounds
[in] Long pointer to a RECT structure specifying the rectangle where the object should be drawn.This parameter is converted to a RECTL structure and passed to IViewObject::Draw.
Return Value
The following HRESULT values can be returned.
| Value | Description |
|---|---|
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 does not support the IViewObject interface. |
E_INVALIDARG |
The function has failed. |
E_OUTOFMEMORY |
The function has failed. |
Remarks
Passing invalid (and under some circumstances NULL) pointers into this function causes an unexpected termination of the application.
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.
To determine whether the platform supports this function, see Determining Supported COM APIs.
Requirements
| Header | ole2.h |
| Library | ole32.lib |
| Windows Embedded CE | Windows CE 2.0 and later |
| Windows Mobile | Windows Mobile Version 5.0 and later |
See Also
Reference
Automation Functions
IViewObject::Draw
DVASPECT
IUnknown
DVASPECT
IViewObject
IUnknown::QueryInterface
Concepts
Determining Supported COM APIs