window 调整大小时位图消失

Question

我有一个简单的 GUI，当我在某个选项卡上时应该会显示图像。我在选项卡进程中有 WM_PAINT 消息，如下所示

case WM_PAINT:
    {
            PAINTSTRUCT psLOGO;
            RECT rcLOGO;
            HDC hdcLOGO;
            //Prepares for painting window
            hdcLOGO = BeginPaint(hwndMonitor, &psLOGO);
            //Retrieves the coordinates of the windows client area
            GetClientRect(hwndMonitor, &rcLOGO);
            //creates a copy of the memory device context 
            HDC hdcDoubleLOGO = CreateCompatibleDC(hdcLOGO);
            HBITMAP Logo = LoadBitmap(GetModuleHandle(NULL), MAKEINTRESOURCE(IDB_BITMAP1));         //Get a bitmap of the picture to be updated
            HBITMAP bmOldLOGO = (HBITMAP)SelectObject(hdcDoubleLOGO, Logo);                                 //Get a handle to the image being replaced
            BitBlt(hdcLOGO, 0, 0, rcLOGO.right, rcLOGO.bottom, hdcDoubleLOGO, 0, 0, SRCCOPY);   //Bit block transfer of the bitmap color data

            SelectObject(hdcDoubleLOGO, bmOldLOGO);
            DeleteDC(hdcDoubleLOGO);
            EndPaint(hwndMonitor, &psLOGO);
            DeleteObject(Logo);
        break;
    }

hwndMonitor 是该特定标签页的句柄

当我打开选项卡时图像显示，但如果我调整 window 的大小，或者如果我最小化并重新打开 GUI，图像将会消失

我必须转到另一个选项卡并返回该选项卡才能取回图像

我在 WM_PAINT 消息中做错了什么吗？

Answer 1

您还必须对 WM_SIZE 消息做出反应。调整 window 的大小不会释放绘制消息。

在 WM_SIZE 只需拨打：

InvalidateRect(hwnd,&rect,TRUE);
UpdateWindow(hwnd);

rect 是具有当前 window 大小的矩形。 Invalidate 标记要重绘的矩形，UpdateWindow 确保它立即重绘。

window 调整大小时位图消失

Bitmap disappears when window is resized

c

mfc

bitmap

visual-studio