[Win32]Set Dialog Bitmap Background

[Member 2965471]

Hi, I've a modal dialog box and I've tried to set a bitmap background:

case WM_ERASEBKGND:
{
HDC memDC, hdc;
HBITMAP hBmp;
BITMAP bmp;
RECT rcc;

hdc = GetDC(hDlg);
hBmp = LoadBitmap(hInst, MAKEINTRESOURCE(IDB_BMP));
memDC = CreateCompatibleDC(hdc);

SelectObject(memDC,hBmp);
GetObject(hBmp, sizeof(bmp), &bmp);
GetClientRect(hDlg,&rcc);

SetStretchBltMode(hdc, HALFTONE);
StretchBlt(hdc,
0,0, rcc.right,rcc.bottom,
memDC,
0,0,bmp.bmWidth, bmp.bmHeight,
SRCCOPY);

DeleteDC(memDC);
DeleteObject(hBmp);
ReleaseDC(hDlg,hdc);

return (INT_PTR)TRUE;
}

this code set a background bitmap, but when I move or resize the dialog controls(edit,button,listbox,...) disappear under the bitmap...what's wrong?how can i repaint correctly the dialog?

[Cheongwadae]

Hi, Try creating the window with the WS_CLIPCHILDREN window style. Also... you might be better off painting the bitmap in WM_PAINT and returning TRUE in your WM_ERASEBKGND handler to avoid flicker.

[Ram Shelke]

Please see the order if u are give the order for bitmap at the last the it will overwrite ur textbox and other things :laugh:

[enhzflep]

Hi, I seem to remember trying this in the past, though failed miserably (presumably for the same reason) I recall using a frame based window, since I could define the background image (as a HBRUSH) in the windows class (ms class, not c++ class) Anyhow, I just ad a few fresh ideas and seem to have resolved the issue. I'll admit I didn't try with a bmp, but since trying to paint a solid color resulted in the same behaviour, I'll (perhaps foolishly?) assume that the solution would be valid if I had. [EDIT: yup - it works just fine with a bitmap too] It's just a simple matter of calling InvalidateRect along with the hWnd of the dialog, the client area (or NULL for all of it) and False - for do not redraw. I.e, just add the line

InvalidateRect(hwndDlg, NULL, false);

after you've done the clean-up and before you return true. Something like so:

        case WM\_ERASEBKGND:
        {
            HDC memDC, hdc;
            HBITMAP hBmp;
            BITMAP bmp;
            RECT rcc;

            hdc = GetDC(hwndDlg);
            hBmp = LoadBitmap(hInst, MAKEINTRESOURCE(IDB\_BITMAP1));

            memDC = CreateCompatibleDC(hdc);

            SelectObject(memDC,hBmp);
            GetObject(hBmp, sizeof(bmp), &bmp);
            GetClientRect(hwndDlg,&rcc);

            SetStretchBltMode(hdc, HALFTONE);
            StretchBlt(hdc, 0,0, rcc.right,rcc.bottom, memDC, 0,0,bmp.bmWidth, bmp.bmHeight, SRCCOPY);

            DeleteDC(memDC);
            DeleteObject(hBmp);
            ReleaseDC(hwndDlg,hdc);
            InvalidateRect(hwndDlg, NULL, false);

        return (INT\_PTR)TRUE;
        }