位图绘制后拖放窗口时闪动现象的解决方案

Windows绘图处理

最新推荐文章于 2025-02-13 11:10:59 发布

原创最新推荐文章于 2025-02-13 11:10:59 发布 · 1.4k 阅读

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#callback

本文介绍了一个Windows应用程序的绘图处理过程，重点展示了如何使用位图资源进行绘制，并通过内存DC来提高绘图效率。文中详细解释了在不同消息处理中进行的资源加载、背景消除、尺寸调整、绘图及销毁等操作。

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
PAINTSTRUCT ps;
RECT rect;

TCHAR szHello[MAX_LOADSTRING];
LoadString(hInst, IDS_HELLO, szHello, MAX_LOADSTRING);

static HDC hdc,hMemDC,hBmpDC;
static HBITMAP hBitmap;
static HBITMAP hMemDCBmp;

switch (message)
{
  case WM_CREATE:
   //读取资源位图
   hBitmap=LoadBitmap(hInst,MAKEINTRESOURCE(IDB_BITMAP1) );
   /*
   hBmpDC=CreateCompatibleDC(hdc);
   SelectObject(hBmpDC,hBitmap);
   */
   return 0;

  case WM_ERASEBKGND:

   return 0;

  case WM_SIZING:

   return 0;
  case WM_SIZE:
   return 0;

  case WM_PAINT:
   hdc=BeginPaint(hWnd, &ps);
   {
    GetClientRect(hWnd,&rect);

    //创建内存DC并将位图句柄选入
    hBmpDC=CreateCompatibleDC(hdc);
    SelectObject(hBmpDC,hBitmap);

    //建立新一个内存DC和位图句柄
    hMemDC=::CreateCompatibleDC(hdc);
    hMemDCBmp=CreateCompatibleBitmap(hdc,rect.right-rect.left,rect.bottom-rect.top);

    HGDIOBJ hBjOld=::SelectObject(hMemDC,hMemDCBmp);

    //先在内存DC上进行整个的画刷填充
    FillRect(hMemDC,&rect,(HBRUSH)GetStockObject(WHITE_BRUSH));

    BitBlt(hMemDC,0,0,rect.right-rect.left,rect.bottom-rect.top,hBmpDC,0,0,SRCCOPY);
    BitBlt(hdc,0,0,rect.right-rect.left,rect.bottom-rect.top,hMemDC,0,0,SRCCOPY);

    //func(rect);
    SelectObject(hMemDC,hBjOld);

    DeleteObject(hMemDCBmp);
    DeleteDC(hBmpDC);
    DeleteDC(hMemDC);
   }
   EndPaint(hWnd,&ps);

   return 0;

  case WM_DESTROY:
   DeleteObject(hBitmap);
   /*
   DeleteObject(hBitmap);
   DeleteObject(hMemDCBmp);
   DeleteDC(hBmpDC);
   DeleteDC(hMemDC);
   */
   PostQuitMessage(0);
   return 0;
  default:
   return DefWindowProc(hWnd, message, wParam, lParam);
   }
   return 0;
}