Controls are flicker madly on resize. I'm trying double buffering but I still ...

ok so for the past half year I've been trying to double buffer my app as it flickers madly when I resize it. Well I was able to Set WM_ERASEBGRND to true to stop it from erasing the Background and under my WM_PAINT my windows procedure I was able to blitblt a gray background on my form so its just not all black.

The thing is is that all of the controls flicker and I even replaced all of my SetWindowPos with DeferWindowPos.

Before this I used WS_EX_COMPOSITED and eve though it does a pretty good job with it, it doesn't update any of my scroll bars. For example if I clicked on a scroll thumb and moved it to the top you have to let go of it for it to update the scroll bar. And when you click down on the buttons for the scroll bars they no longer sink in like they use to which causes problems.

Anyways here is the code I'm using which I found off line and trying to get it to work so my controls stop flickering:

Code:

---

case WM_ERASEBKGND:
    return 1;
    break;

HDC          hdcMem;
HBITMAP      hbmMem;
HANDLE      hOld;
 
PAINTSTRUCT  ps;
HDC          hdc;
RECT Temp_Rect;

case WM_PAINT:
 Temp_Rect=SSMAIN_RECT;
    // Get DC for window
    hdc = BeginPaint(hwnd, &ps);
 
    // Create an off-screen DC for double-buffering
    hdcMem = CreateCompatibleDC(hdc);
    hbmMem = CreateCompatibleBitmap(hdc, SSMAIN_WIDTH,SSMAIN_HEIGHT);
 
    hOld  = (HBITMAP)SelectObject(hdcMem, hbmMem);
 
    // Draw into hdcMem here
 
    // Transfer the off-screen DC to the screen
    Temp_Rect.left=-200;
      Temp_Rect.top=-200;
    FillRect(hdcMem, &Temp_Rect, (HBRUSH) (COLOR_WINDOW+7));
    BitBlt(hdc, 0, 0,  SSMAIN_WIDTH, SSMAIN_HEIGHT, hdcMem, 0, 0, SRCCOPY);
 
    // Free-up the off-screen DC
    SelectObject(hdcMem, hOld);
    DeleteObject(hbmMem);
    DeleteDC    (hdcMem);
 
    EndPaint(hwnd, &ps);
 
    break;

---

Hi,

I had a problem with flickering using tab control. I solved it with the help of sublass procedure
Here how it looks like:

Code:

---

WinTabBase* object = (WinTabBase*)GetWindowLong(hWnd,GWL_USERDATA);

        /*if(uMsg == WM_LBUTTONDOWN)
        {
                //return 0;
        }*/

        if(uMsg == WM_RBUTTONDOWN)
        {
                SendMessage(hWnd,WM_LBUTTONDOWN,wParam,lParam);
                POINT cpos;
                GetCursorPos(&cpos);
                TrackPopupMenu(object->tabmenu,TPM_LEFTALIGN,cpos.x,cpos.y,0,object->handle,0);
        }

        if (uMsg == WM_ERASEBKGND)
        return 1;
    if (uMsg == WM_PAINT)
        {

        ValidateRect (hWnd, NULL);

        HDC hControlDC;
        HDC hMemoryDC;
        RECT rc;     
        HBITMAP hBitmap;   
        HGDIOBJ hSave;     

        GetClientRect (hWnd, & rc);

        hControlDC = GetDC (hWnd);
        hMemoryDC = CreateCompatibleDC (hControlDC);

        hBitmap = CreateCompatibleBitmap (hControlDC, rc.right, rc.bottom);
        hSave = SelectObject (hMemoryDC, hBitmap);

     
        CallWindowProc (object->prevwndproc, hWnd, WM_ERASEBKGND, (WPARAM)hMemoryDC, 0);

       
        CallWindowProc (object->prevwndproc, hWnd, WM_PRINTCLIENT, (WPARAM)hMemoryDC, PRF_CLIENT);

       
        BitBlt (hControlDC, 0, 0, rc.right, rc.bottom, hMemoryDC, 0, 0, SRCCOPY);

        DeleteObject (SelectObject (hMemoryDC, hSave));
        DeleteDC (hMemoryDC);
        ReleaseDC (hWnd, hControlDC);

        return 0;
    }

        if(uMsg == WM_COMMAND)
        {
                object->OnCommand(hWnd,uMsg,wParam,lParam);
        }


    return CallWindowProc (object->prevwndproc, hWnd, uMsg, wParam, lParam);

---

Basically i'm doing the same as you but in subclass procedure. Hope it will help.

Quote:

---

Originally Posted by Sh@dow

Hi,

I had a problem with flickering using tab control. I solved it with the help of sublass procedure
Here how it looks like:

Code:

---

WinTabBase* object = (WinTabBase*)GetWindowLong(hWnd,GWL_USERDATA);

        /*if(uMsg == WM_LBUTTONDOWN)
        {
                //return 0;
        }*/

        if(uMsg == WM_RBUTTONDOWN)
        {
                SendMessage(hWnd,WM_LBUTTONDOWN,wParam,lParam);
                POINT cpos;
                GetCursorPos(&cpos);
                TrackPopupMenu(object->tabmenu,TPM_LEFTALIGN,cpos.x,cpos.y,0,object->handle,0);
        }

        if (uMsg == WM_ERASEBKGND)
        return 1;
    if (uMsg == WM_PAINT)
        {

        ValidateRect (hWnd, NULL);

        HDC hControlDC;
        HDC hMemoryDC;
        RECT rc;     
        HBITMAP hBitmap;   
        HGDIOBJ hSave;     

        GetClientRect (hWnd, & rc);

        hControlDC = GetDC (hWnd);
        hMemoryDC = CreateCompatibleDC (hControlDC);

        hBitmap = CreateCompatibleBitmap (hControlDC, rc.right, rc.bottom);
        hSave = SelectObject (hMemoryDC, hBitmap);

     
        CallWindowProc (object->prevwndproc, hWnd, WM_ERASEBKGND, (WPARAM)hMemoryDC, 0);

       
        CallWindowProc (object->prevwndproc, hWnd, WM_PRINTCLIENT, (WPARAM)hMemoryDC, PRF_CLIENT);

       
        BitBlt (hControlDC, 0, 0, rc.right, rc.bottom, hMemoryDC, 0, 0, SRCCOPY);

        DeleteObject (SelectObject (hMemoryDC, hSave));
        DeleteDC (hMemoryDC);
        ReleaseDC (hWnd, hControlDC);

        return 0;
    }

        if(uMsg == WM_COMMAND)
        {
                object->OnCommand(hWnd,uMsg,wParam,lParam);
        }


    return CallWindowProc (object->prevwndproc, hWnd, uMsg, wParam, lParam);

---

Basically i'm doing the same as you but in subclass procedure. Hope it will help.

---

Thanks Shadow for the code and all.

Does this mean I have to subclass each control that I have on my parent form also?

Also wouldn't that cause problems with certain controls that needs to do its own specific painting as well?

Thanks

I don't know what controls do you use. I had a tab control. I did subclassing only for it, not for controls that is have. I worked for me.
As i understood you have flickering when you resize your parent form. Try to subclass only this parent form and see if it helps.

Quote:

---

Originally Posted by Sh@dow

I don't know what controls do you use. I had a tab control. I did subclassing only for it, not for controls that is have. I worked for me.
As i understood you have flickering when you resize your parent form. Try to subclass only this parent form and see if it helps.

---

How would I go about subclassing the parent form?

Wouldn't that be the same as editing the WM_PAINT message of your windows procedure?

Also I changed the size of bitblt for a certain area.

Now heres the thing, the area where the bitblt is flickers while the rest of my windows doesn't as it leaves a trail of the other controls of the form when I resize it.

Also I have a toolbar,rebar,buttons,static, and a rtf control on my form.

I'm extremely lost with this ><

ok guys since this is not working for me I guess I'm going have to clip the areas where the controls are after I figure out how to do that

>>How would I go about subclassing the parent form?

After creating the form (CreateWindow / CreateWindowEx) do the following:

Code:

---

prevwndproc = (WNDPROC) SetWindowLong (
            handle, GWL_WNDPROC, (LONG) TabCtrlSubclassProc);

---

This code sets a new window procedure TabCtrlSubclassProc which is defined by you.
In the procedure you do your custom job after that do a

Code:

---

CallWindowProc (object->prevwndproc, hWnd, uMsg, wParam, lParam);

---

to call a normal window procedure.

Don't pay attention to the "object->". Since TabCtrlSubclassProc must be defined as static i use object as an additional parameter to the procedure to get handles and other window specific data. I store it using"

Code:

---

SetWindowLong(handle,GWL_USERDATA,(LONG)this);

---

And getting using:

Code:

---

WinTabBase* object = (WinTabBase*)GetWindowLong(hWnd,GWL_USERDATA);

---

This might help:
http://msdn.microsoft.com/en-us/libr...lassing_window

Quote:

---

Originally Posted by Senith

ok guys since this is not working for me I guess I'm going have to clip the areas where the controls are after I figure out how to do that

---

In fact, what you really have to do is to prepare a simple minimalistic compilable project that reproduces your problem, and upload the one here in the thread. usually this is most effective way to investigate your problem and provide a solution to it.

Quote:

---

Originally Posted by Igor Vartanov

In fact, what you really have to do is to prepare a simple minimalistic compilable project that reproduces your problem, and upload the one here in the thread. usually this is most effective way to investigate your problem and provide a solution to it.

---

Ok thanks, I really appreciate that :D.

I have to get some work done though so when I get back I'll upload my program for you all

Thanks again :D ^^

Also I have some images here as well

1. [img] http://phantomworksstudios.com/cpp/flickeringarea.png [/img]
2. [img] http://phantomworksstudios.com/cpp/flickeringpng.png [/img]

Due to my servers restriction I have to have my application within a zip file.
http://phantomworksstudios.com/cpp/ssgdiproblem.zip
There are two.

One is where I only bitblt part of the window which is the top left while the other one I bitblt the whole thing


I'll be back on later all

Thanks again :D ^^

I am not sure why did you deliver executable. Did misunderstood Igor’s post?

Quote:

---

Originally Posted by Igor Vartanov

...prepare a simple minimalistic compilable project that reproduces your problem, and upload the one here in the thread.

---

He meant to create project that reproduces a problem, so we will have a chance to see the cause not the effect.

Quote:

---

Originally Posted by JohnCz

I am not sure why did you deliver executable. Did misunderstood Igor’s post?
He meant to create project that reproduces a problem, so we will have a chance to see the cause not the effect.

---

I'm sorry I did misunderstood that.

If you mean create another project just with the double buffer and some controls then yes I've done that as well and I still get the same results.

Also I don't know why but the only control in my app that doesn't flicker is everything inside of one static control which has it own windows proc and is the parent of a rtf and a list box which doesn't flicker.

Everything else though does flicker so i don't know whats going on

Also my OS is windows 2008 Server Standard and I'm using wxDevC++ as my IDE.

Quote:

---

Originally Posted by Senith

If you mean create another project just with the double buffer and some controls then yes I've done that as well and I still get the same results.

---

OK, you have created project that does the same.
The thing we are asking for is to compress (zip) entire project (solution, project, source and resource files) and attach it to your post.
Before you do that remove Debug and Release folder as well as .ncb file.

This way we can build and debug your code to find what is causing flicker problem.

It seems like your code for double-buffering is in the WndProc for the main window (please confirm).

From your screenshots, it also seems like you do not actually have any controls per se, but rather you are brute-force-drawing the _shapes_ of what look like controls (but aren't actually "real" controls) into the the double buffer.

If so, then you are setting about this in the wrong way. In addition, it explains why a few of your "real" controls (you mentioned a static control and a list box) are behaving properly.

The correct way is to let the controls draw themselves from their own WndProcs (which may be the windows-supplied default WndProc for the control). Then in your main window, do only one thing: set the WS_CLIPCHILDREN style. No need to override the main window's WM_ERASEBKGRD.

Anyway, we look forward to your post of the source code for a minimal program that exhibits the problems you are experiencing.

Mike

Quote:

---

Originally Posted by MikeAThon

It seems like your code for double-buffering is in the WndProc for the main window (please confirm).

From your screenshots, it also seems like you do not actually have any controls per se, but rather you are brute-force-drawing the _shapes_ of what look like controls (but aren't actually "real" controls) into the the double buffer.

If so, then you are setting about this in the wrong way. In addition, it explains why a few of your "real" controls (you mentioned a static control and a list box) are behaving properly.

The correct way is to let the controls draw themselves from their own WndProcs (which may be the windows-supplied default WndProc for the control). Then in your main window, do only one thing: set the WS_CLIPCHILDREN style. No need to override the main window's WM_ERASEBKGRD.

Anyway, we look forward to your post of the source code for a minimal program that exhibits the problems you are experiencing.

Mike

---

(I haven't been online for a while due to work and the internet not working correctly)

And that is correct as the double buffer is within the WndProc of my application.

Also I have the double buffering working now. Some styles of the control such as "WS_CLIPCHILDREN, WS_CLIPSIBLINGS AND WS_EX_TRANSPARENT" were causing some problems with my double buffering which I have working now :D


(Thanks for your info WS_CLIPCHILDREN really appreciate it. I've tried that though with my first application, Everything withing it flickered. )

Also if I misunderstood your post please let me know :D.

Also all the controls on my form are real controls and not custom made (Yet)

Also I ran into the problem with my frame control. For some reason every other control within my app has its background clipped besides my frame(button). So of course everytime I resize the frame will flicker. Now if I add WS_EX_TRANSPARENT to the frame control the background of it is not being up dated as leaves a trail of windows behind. Almost as if its being clipped after I set it to WS_EX_TRANSPARENT.

So I know how to get around that too(an idea that popped into my mind. Explained below) as well, but i'm stuck atm.

I need to be able to draw onto the background of the frame control without erasing the frames border(ie I want to preserve the frames edges and text)

Thanks everyone for your help. It really helped me out.

Also if you guys will still like to see my code let me know and I'll post it. (Still need to clean it up as its a mess now *Working on it*)

Yes, please post ypur code.

Quote:

---

Originally Posted by Senith

Also if I misunderstood your post please let me know :D.

---

I think it's possible that you might have misunderstood. As requested by JohnCz, please post code. Not the actual code of your project, but simple code that demonstrates the flicker that you are encountering.

Generally speaking, with no special effort at all, a resizable dialog will not show any appreciable flicker until there are maybe 50-80 controls on it simultaneously. I don't think you have that many controls. And note that I said that "no special effort" is required for flicker-free performance. Just ensure that WS_CLIPCHILDREN is set. So the fact that you are seeing significant flicker, and the fact that WS_CLIPCHILDREN made it worse, tell me that there is something wrong with the overall architecture, fundamentally.

You state that you are using "actual" controls ("actual" meaning that the controls have their own WndProcs that are probably the default WndProcs supplied by Windows). If so, you are somehow overriding the WM_PAINT messages sent to the controls themselves, and somehow painting the controls in a doulbe-buffering mechanism in the WM_PAINT handler for the parent dialog. Please let us know (show the code) if you are using some abomination like a SendMessage of WM_PAINT to the control from within the WM_PAINT handler of the dialog, like so:

Code:

---

// from the WM_PAINT handler of the parent dialog
// pseudo-code

hdc = BeginPaint()
hdcMem = create memory device context

SendMessage( hwndControl_1, WM_PAINT, hdcMem, 0L );
SendMessage( hwndControl_2, WM_PAINT, hdcMem, 0L );


BitBlt( hdcMem into the hdc );

ReleaseEverything
EndPaint();

---

If you are doing something like this, then it's not a wonder that there is flicker.

Mike

Quote:

---

Originally Posted by MikeAThon

I think it's possible that you might have misunderstood. As requested by JohnCz, please post code. Not the actual code of your project, but simple code that demonstrates the flicker that you are encountering.

Generally speaking, with no special effort at all, a resizable dialog will not show any appreciable flicker until there are maybe 50-80 controls on it simultaneously. I don't think you have that many controls. And note that I said that "no special effort" is required for flicker-free performance. Just ensure that WS_CLIPCHILDREN is set. So the fact that you are seeing significant flicker, and the fact that WS_CLIPCHILDREN made it worse, tell me that there is something wrong with the overall architecture, fundamentally.

You state that you are using "actual" controls ("actual" meaning that the controls have their own WndProcs that are probably the default WndProcs supplied by Windows). If so, you are somehow overriding the WM_PAINT messages sent to the controls themselves, and somehow painting the controls in a doulbe-buffering mechanism in the WM_PAINT handler for the parent dialog. Please let us know (show the code) if you are using some abomination like a SendMessage of WM_PAINT to the control from within the WM_PAINT handler of the dialog, like so:

Code:

---

// from the WM_PAINT handler of the parent dialog
// pseudo-code

hdc = BeginPaint()
hdcMem = create memory device context

SendMessage( hwndControl_1, WM_PAINT, hdcMem, 0L );
SendMessage( hwndControl_2, WM_PAINT, hdcMem, 0L );


BitBlt( hdcMem into the hdc );

ReleaseEverything
EndPaint();

---

If you are doing something like this, then it's not a wonder that there is flicker.

Mike

---

Well what you said so far is pretty much true other then using SendMessage within the WM_PAINT.

Also I somehow manage to fix most of the flickering within my control other then the frame. I'm using WS_CLIPCHILDREN now on my main form as without it would cause all of my controls to flicker.

What ever I did it allowed the CLIPCHILDREN style to work correctly now from the looks of it

Also I read on another forum that you should never send a WM_PAINT message to a control using SendMessage other then windows. So I haven't done that.

Now for the WM_PAINT of my control for the WndProc is as fallows:

Code:

---


    case WM_ERASEBKGND:
      return true ;
    break;
 
    case WM_PAINT:

        HDC          hdcMem;
        HBITMAP      hbmMem;
        HANDLE      hOld;
        PAINTSTRUCT  ps;
        HDC          hdc;
        RECT Temp_Rect;


        RECT Menu_Rect;
        MENUINFO mi;
        GetMenuInfo(GetMenu(hwnd),&mi);   
        RECT Client;
        GetClientRect(hwnd,&Client);   
        RECT Rebar_Rect;
        GetWindowRect(hwnd,&SSMAIN_RECT);
        GetWindowRect(SSMAIN_REBARWINDOW,&Rebar_Rect);
        SSMAIN_WIDTH=SSMAIN_RECT.right-SSMAIN_RECT.left;
        SSMAIN_HEIGHT=SSMAIN_RECT.bottom-SSMAIN_RECT.top;
        Temp_Rect=SSMAIN_RECT;       
       
        hdc = BeginPaint(hwnd, &ps);     
        hdcMem = CreateCompatibleDC(hdc);
        hbmMem = CreateCompatibleBitmap(hdc, SSMAIN_WIDTH,SSMAIN_HEIGHT);
        hOld  = (HBITMAP)SelectObject(hdcMem, hbmMem);
       
        cout<<"PAIN: WP TOP: "    <<SSMAIN_RECT.top<<endl;
        cout <<"SSMAIN Client bottom:"<<Client.bottom<<endl;       
        cout<<"2WP Explorer Rect: L:T:R:B"<<SSMAIN_EXPLORERWINDOW_RECT.left<<":"<<SSMAIN_EXPLORERWINDOW_RECT.top<<":"<<SSMAIN_EXPLORERWINDOW_RECT.right<<":"<<SSMAIN_EXPLORERWINDOW_RECT.bottom<<endl;
       
        FillRect(hdcMem, &Client, (HBRUSH) (COLOR_WINDOW+7));       
        BitBlt(hdc, 0, 0,  SSMAIN_WIDTH, SSMAIN_HEIGHT, hdcMem, 0, 0, SRCCOPY);   
       
        SelectObject(hdcMem, hOld);
        DeleteObject(hbmMem);
        DeleteDC(hdcMem);
        EndPaint(hwnd, &ps);
    break;

---

Also so far I'm still new to the double buffer procedure so I've been looking around sites to find more info out about it and used the basic code below and adopted it from their.

Code:

---

WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);     
        hdcMem = CreateCompatibleDC(hdc);
        hbmMem = CreateCompatibleBitmap(hdc, SSMAIN_WIDTH,SSMAIN_HEIGHT);
        hOld  = (HBITMAP)SelectObject(hdcMem, hbmMem);

//... Code that I added on my self

        SelectObject(hdcMem, hOld);
        DeleteObject(hbmMem);
        DeleteDC(hdcMem);
        EndPaint(hwnd, &ps);
break;

---

If you guys need anything else please let me know.

OK guys now I know why the frame is not working correctly.

Here the thing.

When I turn the frame back into a button and run the program it doesn't flicker at all.

When I turn it back into a frame(Group Box, button) its drawing just the frame and leaves the background transparent so since the background is being clipped by the main window, it shows the frame with a transparent background within the clip region which you all know never updates.

So this means that anything that will cover that area will stay their as it is not being erased which is a good thing.

However! its not good when the frame which is a button is drawing its background transparent.

I need it to have a main background color that fills it without replacing the main frame in this case will just be one solid background on the frame without the frame borders. This I do not want

So the thing is now how can I draw a non transparent background within the frame that does not replace the frame border region?

Thanks and also the frame(button does not have the WS_EX_TRANSPARENT style set)

Thanks again everyone! :D

ok as I feared when you use the BS_GROUPBOX it will automatically set a transparent background which I can't have as the parent clips the area behind it.

So I'm just going to go ahead and draw the control my self. Should be all that hard.

So thank you all for helping me out with this.

really appreciate it!

As your code is written, double buffering is not a cause of your problem and is a complete red-herring.

Which all of us would have been able to tell you immediately, without all the back-and-forth, had you responded to our request for a minimum code sample that demonstrates your problem.

As for your double-buffering code, it does nothing and should be eliminated.

Good luck,
Mike

Quote:

---

Originally Posted by MikeAThon

As your code is written, double buffering is not a cause of your problem and is a complete red-herring.

Which all of us would have been able to tell you immediately, without all the back-and-forth, had you responded to our request for a minimum code sample that demonstrates your problem.

As for your double-buffering code, it does nothing and should be eliminated.

Good luck,
Mike

---

Ok thanks Mike.

I'll remove the double buffer from my WM_PAINt, Better yet I'll remove the whole WM_PAINT.

I think when I tried that last time though and not returning WM_ERASEBKGND to true I think it did cause flicker again.

I can't remember so I'll let you all know what happens.

Also I'm still very new to the whole GDI process.

I still have to manually take over WM_PAINT for my button control or else it will draw the frame with a transparent background which I can't have. As I stated before the clip children clips the rgn behind it. So with the frame bg being transparent I can't have that.

So I have to draw the frame using GDI which I already have working.

Anyways thanks everyone for you help

I really do appreciate it :D ^^