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diff --git a/examples/widgets/doc/src/stickman.qdoc b/examples/widgets/doc/src/stickman.qdoc new file mode 100644 index 0000000000..cffdb64822 --- /dev/null +++ b/examples/widgets/doc/src/stickman.qdoc @@ -0,0 +1,102 @@ +/**************************************************************************** +** +** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/ +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:FDL$ +** GNU Free Documentation License +** Alternatively, this file may be used under the terms of the GNU Free +** Documentation License version 1.3 as published by the Free Software +** Foundation and appearing in the file included in the packaging of +** this file. +** +** Other Usage +** Alternatively, this file may be used in accordance with the terms +** and conditions contained in a signed written agreement between you +** and Nokia. +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \example animation/stickman + \title Stickman Example + + The Stickman example shows how to animate transitions in a state machine to implement key frame + animations. + + \image stickman-example.png + + In this example, we will write a small application which animates the joints in a skeleton and + projects a stickman figure on top. The stickman can be either "alive" or "dead", and when in the + "alive" state, he can be performing different actions defined by key frame animations. + + Animations are implemented as composite states. Each child state of the animation state + represents a frame in the animation by setting the position of each joint in the stickman's + skeleton to the positions defined for the particular frame. The frames are then bound together + with animated transitions that trigger on the source state's propertiesAssigned() signal. Thus, + the machine will enter the state representing the next frame in the animation immediately after + it has finished animating into the previous frame. + + \image stickman-example1.png + + The states for an animation is constructed by reading a custom animation file format and + creating states that assign values to the the "position" properties of each of the nodes in the + skeleton graph. + + \snippet animation/stickman/lifecycle.cpp 1 + + The states are then bound together with signal transitions that listen to the + propertiesAssigned() signal. + + \snippet animation/stickman/lifecycle.cpp 2 + + The last frame state is given a transition to the first one, so that the animation will loop + until it is interrupted when a transition out from the animation state is taken. To get smooth + animations between the different key frames, we set a default animation on the state machine. + This is a parallel animation group which contains animations for all the "position" properties + and will be selected by default when taking any transition that leads into a state that assigns + values to these properties. + + \snippet animation/stickman/lifecycle.cpp 3 + + Several such animation states are constructed, and are placed together as children of a top + level "alive" state which represents the stickman life cycle. Transitions go from the parent + state to the child state to ensure that each of the child states inherit them. + + \image stickman-example2.png + + This saves us the effort of connect every state to every state with identical transitions. The + state machine makes sure that transitions between the key frame animations are also smooth by + applying the default animation when interrupting one and starting another. + + Finally, there is a transition out from the "alive" state and into the "dead" state. This is + a custom transition type called LightningSrikesTransition which samples every second and + triggers at random (one out of fifty times on average.) + + \snippet animation/stickman/lifecycle.cpp 4 + + When it triggers, the machine will first enter a "lightningBlink" state which uses a timer to + pause for a brief period of time while the background color of the scene is white. This gives us + a flash effect when the lightning strikes. + + \snippet animation/stickman/lifecycle.cpp 5 + + We start and stop a QTimer object when entering and exiting the state. Then we transition into + the "dead" state when the timer times out. + + \snippet animation/stickman/lifecycle.cpp 0 + + When the machine is in the "dead" state, it will be unresponsive. This is because the "dead" + state has no transitions leading out. + + \image stickman-example3.png + +*/ |