How WM_PAINT message gets called in MFC,please explain it .
a)Who calls the WM_PAINT message?
b)When it gets called?
c)how it comes to message queue?
Please Explain it
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Answer / vijay
WM_Paint Message will be invoked by the system and not by
any application.
This message is sent when updatewindow or RedrawWindow
Function is called.
Dispactch Message Function dispatches the message , it gets
the message from the GetMessage() or PeekMessage()
Functions.
| Is This Answer Correct ? | 18 Yes | 2 No |
Answer / sai
a)The framework calls this member function
b)This function get called, when Windows or an application
makes a request to repaint a portion of an application's
window.
c)
| Is This Answer Correct ? | 12 Yes | 5 No |
Answer / imtiaz
2.System sends this message to a window procedure when
changes to the window have altered the content of the
client area.
1 & 3 .he message is sent when the UpdateWindow or
RedrawWindow function is called, or by the DispatchMessage
function when the application obtains a WM_PAINT message by
using the GetMessage or PeekMessage function
| Is This Answer Correct ? | 2 Yes | 0 No |
Answer / aditya
The WM_PAINT message is sent when the system or another
application makes a request to paint a portion of an
application's window. The message is sent when the
UpdateWindow or RedrawWindow function is called, or by the
DispatchMessage function when the application obtains a
WM_PAINT message by using the GetMessage or PeekMessage
function.
A window receives this message through its WindowProc
function.
| Is This Answer Correct ? | 1 Yes | 0 No |
Answer / saurabh shakya
n the preceding two examples, a CClientDC object was used to draw in the client area. This approach has the shortcoming that when the window is resized, the graphics are not repainted; in the preceding examples, they must be restored by again choosing the menu item. Using a CPaintDC object and putting the graphics calls into the OnPaint() function changes this behavior, so that the graphics are redrawn each time a WM_PAINT message is sent. This is done in all subsequent examples.
Windows OS sets the paint flag whenever a window gains one or more pixels. Windows OS sends a WM_PAINT message to the window whenever the client area needs to be repainted. When there are no higher-priority messages to be processed, the WM_PAINT message is processed and the window is repainted. The WM_PAINT message will be sent whenever any of the following events occur:
• The window has one or more invalid regions. (This is caused by one or more previously hidden areas of the window being brought back into view. Your window is brought back into view when a window that was above your window is closed or moved. Windows OS keeps track of all the invalid regions since the last repainting occurred and will repaint the invalid rectangle that encloses all invalid regions.)
• The user resizes the window.
• Part of the client area is scrolled.
• The application invalidates the client area, using one of the function calls: CWnd::Invalidate(), CWnd::InvalidateRect(), or CWnd::InvalidateRgn().
| Is This Answer Correct ? | 2 Yes | 1 No |
Answer / jli
When pWnd->Invalidate() get call.
then your pWnd will WM_APINT messages
| Is This Answer Correct ? | 0 Yes | 1 No |
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