asked on

Display of ATL COM Object

I created an ATL COM object that is visible during design time but invisible during runtime. During design time, I print out some text that names the control in the OnDraw function. What I would like to do is to display a square box that looks like a button without the user being able to change the size of the object. Maybe even put a picture representing my control in the button. This is how other objects that are normally not displayed at runtime are shown during design time (e.g. the VB timer control). I would like to do something analogous to the VB timer control.

My Windows drawing skills are very weak. I would appreciate any help I can get in this area.

ShaunWilde

use CComControl::GetAmbientUserMode to determine if you are in design mode (FALSE) or run mode (TRUE)

ShaunWilde

you can then use the above to in you OnDraw handler to either draw a piccie (bitmap) or whatever you display at runtime

eg

HRESULT OnDraw(ATL_DRAWINFO& di)
{
RECT& rc = *(RECT*)di.prcBounds;
Rectangle(di.hdcDraw, rc.left, rc.top, rc.right, rc.bottom);

SetTextAlign(di.hdcDraw, TA_CENTER|TA_BASELINE);
LPCTSTR pszText = _T("ATL 3.0 : MyDraw");
LPCTSTR pszTextDesign = _T("ATL 3.0 : MyDraw Design");

BOOL bUserMode;
GetAmbientUserMode(bUserMode);

if (bUserMode)
{
TextOut(di.hdcDraw,
(rc.left + rc.right) / 2,
(rc.top + rc.bottom) / 2,
pszText,
lstrlen(pszText));
}
else
{
TextOut(di.hdcDraw,
(rc.left + rc.right) / 2,
(rc.top + rc.bottom) / 2,
pszTextDesign,
lstrlen(pszTextDesign));
}

return S_OK;
}

cunningham

ASKER

Thanks for your quick response. However, my question is really "How do you draw a button control similar to the VB timer control"? I'm not sure that the VB timer control is based on the button control, but it looks like it. I am able to do the TextOut stuff as shown in your example but would like something a little nicer.

ShaunWilde

use a bitmap - and bitblt to the screen DC - that is what the IE control does at design time

HBITMAP hBitmap=::LoadBitmap(_Module.GetResourceInstance(),MAKEINTRESOURCE(IDB_MYDRAW));
HDC hDC=::CreateCompatibleDC(di.hdcDraw);
HBITMAP hOldBitmap=(HBITMAP)::SelectObject(hDC,hBitmap);
::StretchBlt(di.hdcDraw,0,0,rc.right,rc.bottom,hDC,0,0,16,16,SRCCOPY);
::SelectObject(hDC,hOldBitmap);
::DeleteDC(hDC);
::DeleteObject(hBitmap);

cunningham

ASKER

Thanks for the information. Like I said, my Windows drawing skills are very weak. Do you know how to set the size of the control so that the user can not change it? The timer control in Visual Basic always snaps back to the same size even if the user tries to change it.

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ShaunWilde

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cunningham

ASKER

That's exactly what I was looking for. I'll remember to add the AutoSize stock property the next time I build a control when I want to control the size. Thanks for all of your help.

ShaunWilde

glad to help :)

cunningham

ASKER

Also, if you take the

[propput, id(DISPID_AUTOSIZE)]
HRESULT AutoSize([in]VARIANT_BOOL vbool);
[propget, id(DISPID_AUTOSIZE)]
HRESULT AutoSize([out,retval]VARIANT_BOOL* pbool);

lines out of the IDL file, then the AutoSize property is not exported and then there is no way for the user to change the size of the object (just like the timer control).