flickering

When my window is resizing ( that's while the window is being draged ), my listbox control flickers
for unknown reason. All the other controls which include "richedit, edit, button, scrollbar" are
working normaly. I'm not doing any drawing myself, i just declared listbox with this:

Code:

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CreateWindowEx(WS_EX_CLIENTEDGE,"ListBox","........",
        WS_CHILD | WS_VSCROLL | LBS_HASSTRINGS | LBS_NOINTEGRALHEIGHT | LBS_NOTIFY,
        10, 10, 200, 100, hWindow, (HMENU)(305), hinstance, NULL);

// i'm adding a few strings to my listbox here, not important
for(int i = 0; i < number_of_books; i++)
{
        SendMessage(lBooks, LB_ADDSTRING, NULL, (LPARAM)books.name[i]);
}

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As you can see my listbox has few strings, one of them is selected.
The only problem is flickering, and i'm not sure why other controls aren't flickering as well.

bahh.... :confused:

I was concerned with the same thing once, but realized that it's is an unfortunate circumstance with GDI rendering. Try other windows and some controls will flicker as well. I just resized a Windows Explorer window around and the tree control flickered like a four-year-old's boogers (or is that "flicked?") and an FTP app I have open with list controls does the same.

Wait for Vista to come out and maybe it'll stop (though, given MS's track record, I doubt it).

no no, this flickering is really unique. And i mean really!!!
It will flicker always, apsolutly always while window is resized...

Look at WM_ERASEBKGND. Try setting the return to true.

Quote:

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Look at WM_ERASEBKGND. Try setting the return to true.

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He can't do that unless he subclasses the EDIT control. And unless he is doing the drawing himself, this is a bad idea.

Make sure that the parent window has the WS_CLIPCHILDREN style.

WM_ERASEBKGND is still an option if the child control covers the parent's client and the parent's WM_ERASEBKGND is the one handled but, equally, given this set of circumstances, setting the parent window's class brush to NULL would achieve the same result. Another factor to consider is the registered class style (as opposed to the window style ie the 'style' parameter of WNDCLASSEX) in which the presence of either the CS_VREDRAW or the CS_HREDRAW style bits can contribute to flicker when resizing the parent.

But use WS_CLIPCHILDREN anyway, as bithub has recommended; it's a lot simpler and very effective.

I have used WS_CLIPCHILDREN from begining, setting window background brush to NULL results
in background beeing invisible, but still my list box flickers.
Heres how i created my main window:

Code:

---

  RegisterClassEx(&objekt);
  hWindow = CreateWindowEx(
        0,
        "objekt",
        " Harry Potter",
        WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN,
        50, 30, 500, 400,
        HWND_DESKTOP,
        NULL,
        hinstance,
        NULL);

---

Heres a very simple application that i wrote, It has a listbox that flickers,
and a resizeable window, compile it and test it... :)

Code:

---

#include <windows.h>
#include <windowsx.h>

HWND                        hWindow;
HDC                        hDC;

#define                WIN32_LEAN_AND_MEAN
#define        KEYDOWN(vk_code) (GetAsyncKeyState(vk_code) & 0x8000 ? 1 : 0)


LRESULT CALLBACK WndProc(HWND hWindow, UINT msg, WPARAM wParam, LPARAM lParam)
{
    HDC hDC;
    PAINTSTRUCT ps;
    RECT rect;
   
    switch(msg)
    {
        case WM_DESTROY:
            PostQuitMessage(0);
            return(0);
            break;
    }
    return DefWindowProc(hWindow, msg, wParam, lParam);   
}   

int WINAPI WinMain(HINSTANCE hinstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    WNDCLASSEX                objekt;
    MSG                msg;

   
    objekt.hInstance = hinstance;
    objekt.lpszClassName = "objekt";
    objekt.lpfnWndProc = WndProc;
    objekt.style = CS_HREDRAW | CS_VREDRAW;
    objekt.cbSize = sizeof(WNDCLASSEX);
    objekt.hIcon = LoadIcon(NULL, IDI_WINLOGO);
    objekt.hIconSm = LoadIcon(NULL, IDI_WINLOGO);
    objekt.hCursor = LoadCursor(NULL, IDC_ARROW);
    objekt.lpszMenuName = NULL;
    objekt.cbClsExtra = 0;
    objekt.cbWndExtra = 0;
    objekt.hbrBackground = (HBRUSH)(COLOR_WINDOW);
   
    RegisterClassEx(&objekt);
    hWindow = CreateWindowEx(
    0,
    "objekt",
    "example",
    WS_OVERLAPPEDWINDOW | WS_SYSMENU,
    0,0,500,500,
    HWND_DESKTOP,
    NULL,
    hinstance,
    NULL);
   
    ShowWindow(hWindow, nCmdShow);
    UpdateWindow(hWindow);
   
        CreateWindowEx(WS_EX_CLIENTEDGE,"ListBox","........",WS_VISIBLE | WS_CHILD | WS_VSCROLL | LBS_HASSTRINGS | LBS_NOINTEGRALHEIGHT | LBS_NOTIFY, 0, 0, 100, 100, hWindow, (HMENU)(305), hinstance, NULL);
    while(TRUE)
    {
        if(PeekMessage(&msg, NULL, NULL, NULL, PM_REMOVE))
        {
                if(msg.message == WM_QUIT){ PostQuitMessage(0); return(0); }
                TranslateMessage(&msg);
                DispatchMessage(&msg);
            }
    }
    return(int)msg.wParam;
}

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As Ken already stated, CS_VREDRAW and CS_HREDRAW both contribute to window flickering, they cause the whole window to be repainted when any rezising takes place, remove them and I can say confidently that the flickering will stop.

P.S. Also, your message loop is rather processor intensive, a better example would be like so:

Code:

---

#include <windows.h>

#define LISTBOX1 1001

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch(msg)
    {
        case WM_CREATE:
                {
                        HWND hList = CreateWindowEx(NULL, "LISTBOX", "",
                                WS_VISIBLE | WS_CHILD | WS_VSCROLL | LBS_HASSTRINGS |
                                LBS_NOINTEGRALHEIGHT | LBS_NOTIFY | WS_BORDER,
                                40, 40, 300, 300, hwnd, (HMENU)LISTBOX1, GetModuleHandle(0), NULL);
                       
                        SendMessage(hList, LB_ADDSTRING, NULL, (LPARAM)"String1");
                        SendMessage(hList, LB_ADDSTRING, NULL, (LPARAM)"String2");
                        SendMessage(hList, LB_ADDSTRING, NULL, (LPARAM)"String3");
                        return 0;
                }
        case WM_CLOSE:
        case WM_DESTROY:
                PostQuitMessage(0);
        return 0;
        default:
                return DefWindowProc(hwnd, msg, wParam, lParam);
    }
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
                                  LPSTR lpCmdLine, int nCmdShow)
{
    WNDCLASSEX wc;
    HWND hwnd;
    MSG Msg;
       
    wc.cbSize        = sizeof(WNDCLASSEX);
    wc.style        = 0;
    wc.lpfnWndProc  = WndProc;
    wc.cbClsExtra    = 0;
    wc.cbWndExtra    = 0;
    wc.hInstance    = hInstance;
    wc.hIcon        = LoadIcon(NULL, IDI_APPLICATION);
    wc.hCursor      = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wc.lpszMenuName  = NULL;
    wc.lpszClassName = "WindowFickerCls";
    wc.hIconSm      = LoadIcon(NULL, IDI_APPLICATION);
       
    if(!RegisterClassEx(&wc))
    {
        MessageBox(NULL, "Window Registration Failed!", "Error!",
            MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }
       
    hwnd = CreateWindowEx(
        WS_EX_CLIENTEDGE,
        "WindowFickerCls",
        "No Flickering",
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 400, 400,
        NULL, NULL, hInstance, NULL);
       
    if(hwnd == NULL)
    {
        MessageBox(NULL, "Window Creation Failed!", "Error!",
            MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }
       
    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);
       
    while(GetMessage(&Msg, NULL, 0, 0) > 0)
    {
        TranslateMessage(&Msg);
        DispatchMessage(&Msg);
    }
    return Msg.wParam;
}

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Ok, i did that, now it works. Thanks.

Code:

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objekt.style = CS_HREDRAW | CS_VREDRAW;

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Should my "objekt.style" contain something or just NULL;

The style property can be NULL, yes.
Other window class styles can be found here: http://msdn.microsoft.com/library/de...boutwindow.asp