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/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
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/*!
\example statemachine/eventtransitions
\title Event Transitions Example
\brief The Event Transitions example shows how to use event transitions,
a feature of \l{The State Machine Framework}.
The Event Transitions Example illustrates how states change when a
user enters or leaves the area of a button. The states are handled by
a QStateMachine object. The screen consists of a QVBoxLayout with a
central button.
When the mouse is outside the button, the text in the button displays
"Outside". When the mouse enters the button, it displays "Inside".
\borderedimage transitions.png
\snippet statemachine/eventtransitions/main.cpp 0
The \c Window class's constructors begins by creating a button.
This button is added to \c layout, which is a QVBoxLayout object.
Then two states are created: \c s1 is the state
"Outside", and \c s2 is the state "Inside".
\snippet statemachine/eventtransitions/main.cpp 1
State \c s1 is the state "Outside" and state \c s2 is state "Inside".
\snippet statemachine/eventtransitions/main.cpp 2
When the button receives an event of type QEvent::Enter and the state
machine is in state \c s1, the machine will transition to state \c s2.
\snippet statemachine/eventtransitions/main.cpp 3
When the button receives an event of type QEvent::Leave and the state
machine is in state \c s2, the machine will transition back to state \c
s1.
\snippet statemachine/eventtransitions/main.cpp 4
Next, state \c s3 is created. \c s3 will be entered when the button
receives an event of type QEvent::MouseButtonPress and the state machine
is in state \c s2. When the button receives an event of type
QEvent::MouseButtonRelease and the state machine is in state \c s3, the
machine will revert to state \c s2.
\snippet statemachine/eventtransitions/main.cpp 5
Finally, the states are added to the machine as top-level states, the
initial state is set to be \c s1 ("Outside"), and the machine is started.
\snippet statemachine/eventtransitions/main.cpp 6
The main() function constructs a Window object that displays the QVBoxLayout
object \c layout with its \c button.
*/
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