C / C++ / MFC

3-Feb-12 3:59

Hi
I am trying to use "InvalidateRect" to paint part of screen. When I move a drawing a little faster, there will be some dirty left on screen.

How can I get rid of the screen dirty? Some code sample would be appreciated.

Best,

Richard MacCutchan3-Feb-12 4:02

Richard MacCutchan

3-Feb-12 4:02

transoft wrote:
there will be some dirty left on screen.

Please clarify, it is not clear where this occurs or what exactly you are referring to. You could also show some of the code you use to repaint your window.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

transoft3-Feb-12 4:11

3-Feb-12 4:11

Thank you for your reply.

I just used following code:

C++

InvalidateRect( rect, true );

Then I picked one drawing using mouse and drag it ( move it) to other place. when I move the drawing very slow (using mouse to move it slowly), it looks OK. But a little bit faster, there will be some dirty (some drawing not cleared) left on screen. Is there a way to avoid this?

Best,

Richard MacCutchan3-Feb-12 4:39

Richard MacCutchan

3-Feb-12 4:39

transoft wrote:
Is there a way to avoid this?

Yes, but I cannot recall the method. I think it's something to do with capturing the mouse and delaying repaint of the Window. Try a search on MSDN for what you are doing and see if you get any good hits.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

Albert Holguin3-Feb-12 5:11

Albert Holguin

3-Feb-12 5:11

What are you invalidating? ...this may be caused by you invalidating only a small portion of a window independent of the rest of the window (causing unnecessary redraws) or by invalidating somewhere where you probably shouldn't (also causing unnecessary redraws).

You really need to share more of the code for a more definitive solution.

transoft3-Feb-12 6:02

3-Feb-12 6:02

Yes, I just want to invalidate the drawing area that I am moving.

What I am doing is:

(1) while "mouse moving", I send out "InvalidateRect".
(2) do the Invalidating job

I think the problem coming from the delay "InvalidateRect" and actual paint. I also tried "RedrawWindow" without any success.

Thank you for your reply!

SledgeHammer013-Feb-12 14:14

SledgeHammer01

3-Feb-12 14:14

InvalidateRect() does what it is supposed to do. If you are leaving mess on the screen, it is because your rectangle is wrong / too small / etc. Or if your Invalidate / Paint rectangle is mismatched. What I mean is, if you move the mouse fast, you might erase 0,0,100,100, but by the time you get to the paint, you are working on rectangle 10,10,110,110. Also, how are you getting the rect to paint? The one that comes in through GetUpdateRect() is often wrong / slightly off.

transoft4-Feb-12 4:34

4-Feb-12 4:34

Thank you very much for your reply.

I calculated the drawing rectangle that I need to move. AND I also enlarge the rectangle by 1.3 factor. I am sure the problem is not from the region that needed to be updated.

The problem is that when I move the drawing slowly, everything is OK, but a little faster, there will be some mess on screen.

Thanks again!

SledgeHammer014-Feb-12 7:49

SledgeHammer01

4-Feb-12 7:49

transoft wrote:
I am sure the problem is not from the region that needed to be updated.

Then you would be highly mistaken sir! Smile | :)

Win32 drawing is message based (WM_ERASEBKGND & WM_PAINT). When you move slowly, you are getting all the messages point by point and your painting works correctly. When you are moving quickly, you MAY NOT get all messages. Windows is not going to send you a message for every single point when you are moving the mouse around like a crazy person! It compensates for that by skipping points.

What I indicated in my original response is your issue. 100% guaranteed.

You draw something at 0,0,100,100 and then move the mouse so quickly, the system never sends you an erase / paint cycle for 0,0,100,100 because you are already at 10,10,110,110.

For example:

Enlarging the rectangle by 0.0 may work for moving the mouse up to "10MPH"
Enlarging the rectangle by 1.0 may work for moving the mouse up to "20MPH"
Enlarging the rectangle by 2.0 may work for moving the mouse up to "50MPH"

So you get excited and enlarge the rectangle by 3.0 and everything works perfectly, right? NO. Everything works perfectly on YOUR machine which is a super duper gaming machine with a high end video card.

Then you take your app over to Bobs machine which has a lousy graphics card, anti-virus app running in the background and is cluttered with spyware from all his porn sites.

On Bob's machine, your app only works for moving the mouse up to "7MPH" and you get furious and start foaming at the mouth all angry!

True story Smile | :)

.

I have been doing Win32 GUI apps for 16 years and am a custom control master. I am fully aware of how the system works and all the nuances Smile | :)

.

BOTTOM LINE: if your update rectangle was correct, you wouldn't be here posting your question, now would you? Smile | :)

Over the years, I have learned that painting by update region is often a practice in futility and you will never get it perfect across machines at every mouse speed / video card combo.

You **MUST** double buffer your screens and keep track of what you drew on. DO NOT RELY ON WINDOWS TO SEND YOU ALL POINTS!!!

One other option is to realize that today is the year 2012 and move on to a "big boy" architecture like WPF where we don't worry about such nonsense anymore Smile | :)

. MFC was fine in 1986. Sorry Smile | :)

, had to be said Smile | :)

. I don't program in Win32 / MFC anymore after all these years because I refuse to deal with crap like pixel droppings anymore and instead focus on the application Smile | :)

.

But my response still stands. Your update rectangle can NOT be correct or your app would be working. It is not necessarily your fault... Win32 just doesn't feel like sending you all the information you need to do your "optimized" drawing.

CAsynSocket connection problem

MikeTHennessy7-Feb-12 12:10

MikeTHennessy

7-Feb-12 12:10

Several things come to mind:
1. The parameter "rect" refers to only the "area" that will be invalidated. If the objects you're moving occupy the entire client area, try using the function as follows: InvalidateRect(NULL);

2. With a little more work you may want to "buffer" output for speedier and flicker free operation.

3. Examine GDI+ as an alternative

ForNow2-Feb-12 16:03

ForNow

2-Feb-12 16:03

I am getting a 0 Return Code from CAsynSocket::connect doing GetLasterror I am getting
WSAEWOULDBLOCK 10035 (waitting for connection to complete)

However my CAsynSocket::Onconnect overridable is never called to complete the connection

Any Suggestion would be helpfull

«_Superman_»2-Feb-12 18:07

«_Superman_»

2-Feb-12 18:07

Please post the OnConnect function that you've written.

«_Superman_»
I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

Polymorphism in C

ForNow2-Feb-12 18:49

ForNow

2-Feb-12 18:49

My CAsynsocket clas lives whitin a CWIinThread Class
class SockCLeintThread : public CWinThread {
public:
DECLARE_DYNCREATE(SockCLeintThread)
// DECLARE_DYNAMIC(SockCLeintThread)
// IMPLEMENT_DYNAMIC(SockCLientThread)
public:
CWnd *sendwindow;
CWnd *call_wnd;
CString buffer;
char thread_id[15];;
SockClient thisocket; // Socket to do ocommunication
virtual BOOL InitInstance(); // Just for starters
virtual int Run(); // keep on moving
// virtual int ExitInstance();
void receive_work(WPARAM , LPARAM);
void Sendit(WPARAM, LPARAM);
void Receiveit(WPARAM, LPARAM);
void sockoper(WPARAM, LPARAM);
LPCTSTR ipaddr;
UINT port;
BOOL idle; // looking for work
SockCLeintThread();
~SockCLeintThread();
struct {
unsigned int is_connected : 1;
} flags;

protected:
DECLARE_MESSAGE_MAP()

};

My CASynsocket defination

class SockClient : public CAsyncSocket
{
 public:
      // SockCleint(char *sockptr);
        SockClient();
        char *sockbuffer;       // send and receive buffer
        int num_buff;
        CWnd *send_wnd;
        int thread_no;
   protected:
                         // window to send message to
        virtual void OnReceive(int nErrorCode);
        virtual void OnSend(int nErrorCode);
        virtual void OnConnect(int nErrorCode);
        virtual void OnClose(int nErrorCode);


};

In the initinstance for the CWinThread I do a create a get a good return code "1" howver for the connect I get a 0 GetLastError return

WSAEWOULDBLOCK
10035

OOL SockCLeintThread::InitInstance()
   {
int error_code;
CHERC_CMDApp* main_app;


            main_app = (CHERC_CMDApp *)AfxGetApp();



       SockCLeintThread* current = dynamic_cast<SockCLeintThread*>(current);

           SetThreadName(m_nThreadID,thread_id);

         if(thisocket.Create(port,SOCK_STREAM,FD_READ|FD_WRITE|FD_CONNECT,NULL)== 0)
         {
                         error_code =  thisocket.GetLastError();
                  }

    //                  thisocket.AsyncSelectFD_READ|FD_WRITE|FD_CONNECT|FD_CLOSE);  //REQUEST NOTIFICATION

                  

          main_app = (CHERC_CMDApp *)AfxGetApp();


          if( thisocket.Connect(ipaddr,port) == 0)
                  {
                         error_code =  thisocket.GetLastError();
                  }
           else
              current->flags.is_connected = 1;





    return TRUE;                                                   // [11]
   }

here is my ::OnConnect overridable

void SockClient :: OnConnect(int nErrorcode)
  {

      CHERC_CMDApp* main_app;

            main_app = (CHERC_CMDApp *)AfxGetApp();

    //   SockCLeintThread* current;
       SockCLeintThread* current = dynamic_cast<SockCLeintThread*>(current);
      current = (SockCLeintThread*)AfxGetThread();
       UNREFERENCED_PARAMETER(nErrorcode);
          CAsyncSocket::OnConnect(nErrorcode);
       current->flags.is_connected = 1;
  //    if(nErrorcode == WSAETIMEDOUT)
    //    Connect(current->ipaddr,current->port);

        AsyncSelect(FD_WRITE);
   //    main_app->pevent->SetEvent();
  }

Thanks

pyunwang2-Feb-12 19:00

pyunwang

2-Feb-12 19:00

sometimes the operation of the non-blocking (a nonblocking) sockets, can not be completed immediately, it will return this error code. This error is not a serious error, the operation will again after some time try to perform. Since the establishment of the connection will inevitably take some time, so sometimes a nonblocking SOCK_STREAM socket call CONNECT back to the WSAEWOULDBLOCK (10 035) error code