Lagged GDI paint. can't find source of problem

I'm working on a networked paint program which is starting to work fine, except that after a paint command is sent to the server and the server echos it back, there is a a 10-30 second lag in the program, then it goes back to normal. Does anyone know what might be causing this? There is a lot of code, so I have only posted select pieces. The lag occurs after the command is received and drawn, but I don't see what the program is doing after that, where the lag could come from.


This is the process which handles all the socket programming. I'm working with a winsock wrapper class to handle all network programming (of which I've worked through and tested and am positive works fine).

Code:

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LRESULT WINAPI TopDlgProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{

        //socket activity on the server half of the program.
        if (uMsg == perServer.getEvent())
        {
                nEventCode = WSAGETSELECTEVENT(lParam);
                nErrorCode = WSAGETSELECTERROR(lParam);
                switch (nEventCode)
                {
                        case FD_READ:
                                ZeroMemory(crchat, 1024);

                                lstUser.reset();
                                while (lstUser.next()) {
                                        if (lstUser.getData().getSocket() == (SOCKET)wParam) break;
                                }
                                lstUser.getData().perReadLine(crchat, 1024, "DELIMITER");

                                perServer.perSend(crchat, 1024, lstUser.getData().getSocket());

                                //lstUser.reset();
                                //while (lstUser.next()) {
                                //        perServer.perSend(crchat, 1024, lstUser.getData().getSocket());
                                //}

                                return false;
                                break;
                        case FD_WRITE:
                                return false;
                                break;
                        case FD_ACCEPT:
                                lstUser.insert(perServer.perAccept());
                                AppendChatBuff("[Server] User Connected!");
                                return false;
                                break;
                        case FD_CLOSE:
                                AppendChatBuff("[Server] User Left!");
                                return false;
                                break;
                        default:
                                return false;
                                break;
                }
        }

        //occurs when socket activity occurs on client
        if (uMsg == perClient.getEvent())
        {
                nEventCode = WSAGETSELECTEVENT(lParam);
                nErrorCode = WSAGETSELECTERROR(lParam);
                switch (nEventCode)
                {
                        case FD_READ:
                                ZeroMemory(crchat, 1024);
                                perClient.perReadLine(crchat, 1024, "DELIMITER");
                                DecodeMessage(crchat, 1024);
                                break;
                        case FD_WRITE:
                                break;
                        case FD_CONNECT:
                                if (nErrorCode)
                                {
                                        perClient.perClose();
                                        AppendChatBuff("[Client] Connection failed!");
                                        break;
                                }
                                AppendChatBuff("[Client] Connected!");
                                break;
                        case FD_CLOSE:
                                perClient.perClose();
                                AppendChatBuff("[Client] Disconnected!");
                                break;
                        default:
                                break;
                }
        }

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Here is the canvas dialog process, in which everything is painted.

Code:

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LRESULT WINAPI CanvasDlgProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam){
        switch(uMsg)
        {
        case WM_LBUTTONDOWN:
                if (GetForegroundWindow() != hDlgCanvas) return false;
                crDrawing.pStart.x = LOWORD(lParam);
                crDrawing.pStart.y = HIWORD(lParam);
                crDrawing.LineWidth = 5;
                crDrawing.cRed = GetRValue(crForeground);
                crDrawing.cBlue = GetBValue(crForeground);
                crDrawing.cGreen = GetGValue(crForeground);
                if (crDrawing.ToolID == PIXELBRUSH)
                {
                        crDrawing.MakePacket();
                        perClient.perSend(crDrawing.szPacket, 17);
                }
                break;
        case WM_LBUTTONUP:
                if (GetForegroundWindow() != hDlgCanvas) return false;
                crDrawing.pEnd.x = LOWORD(lParam);
                crDrawing.pEnd.y = HIWORD(lParam);
                crDrawing.MakePacket();
                perClient.perSend(crDrawing.szPacket, 17);
                break;
        case WM_MOUSEMOVE:
                if (GetForegroundWindow() != hDlgCanvas) return false;
                if ((wParam == MK_LBUTTON) && (crDrawing.ToolID == PIXELBRUSH))
                {
                        crDrawing.pStart.x = LOWORD(lParam);
                        crDrawing.pStart.y = HIWORD(lParam);
                        crDrawing.LineWidth = 5;
                        crDrawing.cRed = GetRValue(crForeground);
                        crDrawing.cBlue = GetBValue(crForeground);
                        crDrawing.cGreen = GetGValue(crForeground);       
                        crDrawing.MakePacket();
                        perClient.perSend(crDrawing.szPacket, 17);
                }
        case WM_CTLCOLORDLG:
                HBRUSH hbrTemp;
                hbrTemp = CreateSolidBrush(RGB(255, 255, 255));
                return (LRESULT)hbrTemp;
                break;
        case WM_DESTROY:
                break;
        }
        return false;
}

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Here is the function which recieves a command to draw an object and then draws it accordingly. I know it's a bad idea to create an HDC everytime, but I changed it to this way to try and isolate the problem. Even when hdcCanvas was a global (and hPen as well), it still did the lagging.

Code:

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void DrawObj(CPaintTool crPaintTool)
{
        HDC hdcCanvas = GetDC(hDlgCanvas);
        COLORREF crColor = RGB(crPaintTool.cRed, crPaintTool.cGreen, crPaintTool.cBlue);
        HPEN hPen = CreatePen(PS_SOLID, crPaintTool.LineWidth, crColor);
        SelectObject(hdcCanvas, (HGDIOBJ)hPen);

        switch (crPaintTool.ToolID)
        {
        case PIXELBRUSH:
                MoveToEx(hdcCanvas, crPaintTool.pStart.x, crPaintTool.pStart.y, NULL);
                LineTo(hdcCanvas, crPaintTool.pStart.x, crPaintTool.pStart.y);
                break;

        case LINE:
                MoveToEx(hdcCanvas, crPaintTool.pStart.x, crPaintTool.pStart.y, NULL);
                LineTo(hdcCanvas, crPaintTool.pEnd.x, crPaintTool.pEnd.y);
                break;

        case RECTANGLE:
                MoveToEx(hdcCanvas, crPaintTool.pStart.x, crPaintTool.pStart.y, NULL);
                LineTo(hdcCanvas, crPaintTool.pStart.x, crPaintTool.pEnd.y);
                LineTo(hdcCanvas, crPaintTool.pEnd.x, crPaintTool.pEnd.y);
                LineTo(hdcCanvas, crPaintTool.pEnd.x, crPaintTool.pStart.y);
                LineTo(hdcCanvas, crPaintTool.pStart.x, crPaintTool.pStart.y);
                break;

        case CIRCLE:
                Ellipse(hdcCanvas, crPaintTool.pStart.x, crPaintTool.pStart.y, crPaintTool.pEnd.x, crPaintTool.pEnd.y);
                break;

        default:
                break;
        }
        DeleteObject(hPen);
        ReleaseDC(hDlgCanvas, hdcCanvas);
        DeleteDC(hdcCanvas);
}

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I can't even trace where the lag is comming from. Doing a debug and stepping through leads me nowhere. I appreciate time taken to look through this.