Question

我已经在Winapi计时器中设置了捕获屏幕截图的过程。我可以成功地将所述图像blit到窗口，但我怎么会反复这样做，让我们说每1-2秒？

我所拥有的电流代码可以一次点亮1-2秒，但它不会正确地向窗口显示（图像放错位置）。

我该如何做到这一点？

    #include <windows.h>
#include <iostream>

#include <windowsx.h>

  #define TIMERID 3232
 /*  Declare Windows procedure  */
  LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

 RECT rectangle{
   50,
   50,
   690,
   409
 };

 /*  Make the class name into a global variable  */
  char szClassName[ ] = "CodeBlocksWindowsApp";


 HDC handle_WindowDC;
  HDC handle_MemoryDC;
    HDC handle_ScreenDC;
    //BITMAP bitmap;
    HBITMAP handle_Bitmap;
     int x, y;
     HWND hand;

int WINAPI WinMain (HINSTANCE hThisInstance,
                 HINSTANCE hPrevInstance,
                 LPSTR lpszArgument,
                 int nCmdShow)
{
HWND hwnd;               /* This is the handle for our window */
MSG messages;            /* Here messages to the application are saved */
WNDCLASSEX wincl;        /* Data structure for the windowclass */

/* The Window structure */
wincl.hInstance = hThisInstance;
wincl.lpszClassName = szClassName;
wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
wincl.cbSize = sizeof (WNDCLASSEX);

/* Use default icon and mouse-pointer */
wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
wincl.lpszMenuName = NULL;                 /* No menu */
wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
wincl.cbWndExtra = 0;                      /* structure or the window instance */
/* Use Windows's default colour as the background of the window */
wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

/* Register the window class, and if it fails quit the program */
if (!RegisterClassEx (&wincl))
    return 0;

/* The class is registered, let's create the program*/
hwnd = CreateWindowEx (
       0,                   /* Extended possibilites for variation */
       szClassName,         /* Classname */
       "Code::Blocks Template Windows App",       /* Title Text */
       WS_OVERLAPPEDWINDOW, /* default window */
       CW_USEDEFAULT,       /* Windows decides the position */
       CW_USEDEFAULT,       /* where the window ends up on the screen */
       1600,                 /* The programs width */
       900,                 /* and height in pixels */
       HWND_DESKTOP,        /* The window is a child-window to desktop */
       NULL,                /* No menu */
       hThisInstance,       /* Program Instance handler */
       NULL                 /* No Window Creation data */
       );

/* Make the window visible on the screen */
ShowWindow (hwnd, nCmdShow);


        SetTimer(hwnd, TIMERID, 1000, (TIMERPROC)NULL);
/* Run the message loop. It will run until GetMessage() returns 0 */
while (GetMessage (&messages, NULL, 0, 0))
{
    /* Translate virtual-key messages into character messages */
    TranslateMessage(&messages);
    /* Send message to WindowProcedure */
    DispatchMessage(&messages);
}

/* The program return-value is 0 - The value that PostQuitMessage() gave */
return messages.wParam;
}


/*  This function is called by the Windows function DispatchMessage()  */

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)                  /* handle the messages */
{

    case WM_CREATE:{

    }

        //hand = CreateWindowEx(NULL, "STATIC", "", SS_BITMAP|WS_VISIBLE, 500,300, 640 ,360 , hwnd, HMENU(IDCSTATIC_BITMAP), GetModuleHandle(NULL), NULL);        }
    break;
    case WM_TIMER:
        switch(LOWORD(wParam)){

            case TIMERID:{

                //MessageBox(NULL,NULL,NULL,NULL);
                    handle_ScreenDC = GetDC(NULL);
                    handle_MemoryDC = CreateCompatibleDC(handle_ScreenDC);



                    x = GetDeviceCaps(handle_ScreenDC, HORZRES);
                    y = GetDeviceCaps(handle_ScreenDC, VERTRES);

                handle_Bitmap = CreateCompatibleBitmap(handle_ScreenDC, 640, 360);

                SelectObject(handle_MemoryDC, handle_Bitmap);
                StretchBlt(handle_MemoryDC, 0, 0, 640, 360, handle_ScreenDC, 0, 0, x, y, SRCCOPY);
                UpdateWindow(hwnd);
                BitBlt(handle_WindowDC, 50, 50, x, y, handle_MemoryDC, 0, 0, SRCCOPY);


            }
            break;
    }break;

    case WM_PAINT:{

        PAINTSTRUCT paintstruct;
        handle_WindowDC = BeginPaint(hwnd, &paintstruct);
        //BitBlt(handle_WindowDC, 50, 50, x, y, handle_MemoryDC, 0, 0, SRCCOPY);
        EndPaint(hwnd, &paintstruct);

    }
    break;
    case WM_DESTROY:
        PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
        break;

    case WM_LBUTTONDOWN:{

        std::cout <<"\nx: " << GET_X_LPARAM(lParam) << "\ny: " << GET_Y_LPARAM(lParam);
        tagPOINT point;
        point.x = GET_X_LPARAM(lParam);
        point.y = GET_Y_LPARAM(lParam);

        if( PtInRect(&rectangle, point)){

            int x, y;
            x = 2.5*(point.x - 50);
            y = 2.5*(point.y - 50);


            //I juse use setcursorpos for now, but when connecting to server.exe i will do a send() and send x,y coordinates along with
            //a click or rightclick, or whatever.
            SetCursorPos(x, y);

        }

    }
    break;
    default:                      /* for messages that we don't deal with */
        return DefWindowProc (hwnd, message, wParam, lParam);
}

return 0;
}

Answer 1

您正在使用WM_PAINT中的DC在WM_TIMER代码中绘制，在EndPaint()期间DC将被释放 - MSDN Docs表示“EndPaint发布了显示BeginPaint检索到的设备上下文'。

另外，请确保使用ReleaseDC(handle_ScreenDC)和DeleteObject(handle_MemoryDC)

发布您的DC

WM_TIMER的代码应该使矩形无效，在WM_PAINT期间完成所有绘画。有关示例代码，请参阅this article。

正确的方法反复blit到窗口DC？

1 个答案: