altering bitmap before display

I load a bitmap resource
   hBitmap = LoadBitmap(hInst,MAKEINTRESOURCE(MY_BITMAP));
and would like to edit it before displaying it in a dialog box static picture control
     SendDlgItemMessage(hDlg,MY_PICTURE_CONTROL,STM_SETIMAGE,(WPARAM)IMAGE_BITMAP,(LPARAM)hBitmap);

I have tried creating a DC, selecting the bitmap into it, and doing some drawing, but the unchanged bitmap is always displayed in the control.
Thank You
IgnatzAsked:
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MarscConnect With a Mentor Commented:
Try hMemDC = CreateCompatibleDC (NULL);
I´ve allways used this function.
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cookreCommented:
Doesn't painting to the DC effect only the image as displayed on that device and not the original bitmap selected into it?  And if you want to save the changes you have to create a new bitmap from the DC?
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chensuCommented:
It should work. Show your code please.
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IgnatzAuthor Commented:
hBitmap = LoadBitmap(hInst,MAKEINTRESOURCE(MY_BITMAP));
GetObject(hBitmap,sizeof(BITMAP),&bmp);
hdcMem = CreateDC("DISPLAY","DISPLAY",NULL,NULL);
hOldBitmap = (HBITMAP)SelectObject(hdcMem,hBitmap);
rect.left = rect.top = 0;
rect.right = bmp.bmWidth;
rect.bottom = bmp.bmHeight;
hBrush = (HBRUSH)GetStockObject(BLACK_BRUSH);
FillRect(hdcMem,&rect,hBrush);
SendDlgItemMessage(hDlg,COLOR_EXAMPLE,STM_SETIMAGE,(WPARAM)IMAGE_BITMAP,(LPARAM)hBitmap);
SelectObject(hdcMem,hOldBitmap);
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IgnatzAuthor Commented:
did the trick.
Thanks
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MarscCommented:
Well... I am glad to having been helpfull....
Just to complete the answer a little.

NULL Should be another existing HDC
When you use NULL as a parameter, windows assumes the screen as DC.

I guess you was failing at the "SelectObject" line because there was No DC created.....
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chensuCommented:
Marsc> there was No DC created.....

CreateDC("DISPLAY","DISPLAY",NULL,NULL) creates a DC associated with the actual display device while CreateCompatibleDC(NULL) creates a memory DC, which is what you need.
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