What Is HDC C++?

What is HDC C++? HDC : Stands for Handle to Device Context. this structure is used to obtain graphical components. PAINTSTRUCT : This is the Paint Structure. this structure allows to draw shapes.

What is HDC MSDN?

The GetDC function retrieves a handle to a device context (DC) for the client area of a specified window or for the entire screen. You can use the returned handle in subsequent GDI functions to draw in the DC.

What is HDC handle?

The printer device context handle is the Windows Handle to a Device Context (HDC). The value of the PRINTER-HDC attribute is meaningless when the SESSION:PRINTER-CONTROL-HANDLE has a value of zero (0) or the Unknown value ( ? ).

What is Startpaint?

The BeginPaint function prepares the specified window for painting and fills a PAINTSTRUCT structure with information about the painting.

What is the purpose of WM destroy message?

It is sent to the window procedure of the window being destroyed after the window is removed from the screen. This message is sent first to the window being destroyed and then to the child windows (if any) as they are destroyed.

Related faq for What Is HDC C++?

What is Wm_command?

The WM_COMMAND message is sent when the user selects a command item from a menu, when a control sends a notification message to its parent window, or when an accelerator keystroke is translated.

What is CDC and HDC?

CDC is a C++ class which - to a reasonable approximation - encapsulates an HDC, which is a handle to a device context. The documenation which you link to describes a conversion operator , which is a C++ construct that classes can supply to allow implicit conversion from an instance of a class to some other type.

Is foreground a window?

The foreground window (the result of of GetForegroundWindow() ) is the window that's currently getting input regardless of its relationship to the calling thread. The active window is essentially localized to your application; the foreground window is global to the system.

What is ReleaseDC?

The ReleaseDC function releases a device context (DC), freeing it for use by other applications. The effect of the ReleaseDC function depends on the type of DC. It frees only common and window DCs. It has no effect on class or private DCs.

What is device context win32?

A device context is a structure that defines a set of graphic objects and their associated attributes, as well as the graphic modes that affect output.

When should I call DestroyWindow?

When the user directly closes a frame window, this action generates the WM_CLOSE message, and the default response to this message is to call DestroyWindow. When a parent window is destroyed, Windows calls DestroyWindow for all its children.

What is Wm_syskeydown?

The WM_SYSKEYDOWN message indicates a system key, which is a key stroke that invokes a system command. There are two types of system key: ALT + any key. F10.

What is Wm_close?

The WM_CLOSE message gives you an opportunity to prompt the user before closing the window. If you really do want to close the window, call the DestroyWindow function. case WM_CLOSE: if (MessageBox(hwnd, L"Really quit?", L"My application", MB_OKCANCEL) == IDOK) DestroyWindow(hwnd); // Else: User canceled.

What is Lparam and Wparam?

According to this, LPARAM is defined as LONG_PTR , which in 64-bit Windows is a signed, 64-bit value. WPARAM is defined as UINT_PTR , which in 64-bit Windows is an unsigned, 64-bit value. If you are defining your own message, you might want to assign its parameters accordingly.

What is CDC MFC?

CDC is the most fundamental class to draw in MFC. The CDC object provides member functions to perform the basic drawing steps, as well as members for working with a display context associated with the client area of a window.

Which function is used to select the particular GDI object created in MFC application?

To use the GDI objects you've created, select them into the printer device context in the OnPrint member function. If you need different GDI objects for different pages of the document, you can examine the m_nCurPage member of the CPrintInfo structure and select the GDI object accordingly.

What is ForegroundLockTimeout?

More Information. This behaviour is controlled by the registry setting "ForegroundLockTimeout". This is specifies the length of time (following user input) during which the system keeps applications from moving into the foreground.

What is SetForegroundWindow?

SetForegroundWindow makes the specified window the current foreground window and gives it the focus. This function should only be used with windows which your program owns. The function tells Windows to somehow draw the user's attention to the window, such as by flashing its icon in the taskbar.

How do you set a foreground window?

Making a window the foreground window requires more than just calling the SetForegroundWindow API. You must first determine the foreground thread and attach it to your window, using AttachThreadInput, then call SetForegroundWindow. That way they can share input states.

How do you destroy windows?

What is window device context?

A device context is a Windows data structure containing information about the drawing attributes of a device such as a display or a printer. All drawing calls are made through a device-context object, which encapsulates the Windows APIs for drawing lines, shapes, and text.

What is PostQuitMessage?

The PostQuitMessage function posts a WM_QUIT message to the thread's message queue and returns immediately; the function simply indicates to the system that the thread is requesting to quit at some time in the future. The exit value returned to the system must be the wParam parameter of the WM_QUIT message.

What is Wh_keyboard_ll?

WH_KEYBOARD_LL. The WH_KEYBOARD_LL hook enables you to monitor keyboard input events about to be posted in a thread input queue.

What is 0x8000 C++?

The 0x8000 bit of GetAsyncKeyState gives you the real time state of the key. This means that at the moment you call the function, the bit will be set if the key is currently being held down. or it will be clear if the key is not being held down.

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