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Leap Motion C++ API Reference
0.8.0
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The Listener class defines a set of callback functions that you can override in a subclass to respond to events dispatched by the Controller object. More...
Public Member Functions | |
Listener () | |
Constructs a Listener object. | |
virtual void | onConnect (const Controller &) |
Called when the Controller object connects to the Leap Motion software, or when this Listener object is added to a Controller that is already connected. | |
virtual void | onDisconnect (const Controller &) |
Called when the Controller object disconnects from the Leap Motion software. | |
virtual void | onExit (const Controller &) |
Called when this Listener object is removed from the Controller or the Controller instance is destroyed. | |
virtual void | onFocusGained (const Controller &) |
Called when this application becomes the foreground application. | |
virtual void | onFocusLost (const Controller &) |
Called when this application loses the foreground focus. | |
virtual void | onFrame (const Controller &) |
Called when a new frame of hand and finger tracking data is available. | |
virtual void | onInit (const Controller &) |
Called once, when this Listener object is newly added to a Controller. | |
virtual | ~Listener () |
Destructs this Listener object. | |
The Listener class defines a set of callback functions that you can override in a subclass to respond to events dispatched by the Controller object.
To handle Leap Motion events, create an instance of a Listener subclass and assign it to the Controller instance. The Controller calls the relevant Listener callback function when an event occurs, passing in a reference to itself. You do not have to implement callbacks for events you do not want to handle.
The Controller object calls these Listener functions from a thread created by the Leap Motion library, not the thread used to create or set the Listener instance.
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inline |
Constructs a Listener object.
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inlinevirtual |
Destructs this Listener object.
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inlinevirtual |
Called when the Controller object connects to the Leap Motion software, or when this Listener object is added to a Controller that is already connected.
controller | The Controller object invoking this callback function. |
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inlinevirtual |
Called when the Controller object disconnects from the Leap Motion software.
The controller can disconnect when the Leap Motion device is unplugged, the user shuts the Leap Motion software down, or the Leap Motion software encounters an unrecoverable error.
Note: When you launch a Leap-enabled application in a debugger, the Leap Motion library does not disconnect from the application. This is to allow you to step through code without losing the connection because of time outs.
controller | The Controller object invoking this callback function. |
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inlinevirtual |
Called when this Listener object is removed from the Controller or the Controller instance is destroyed.
controller | The Controller object invoking this callback function. |
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inlinevirtual |
Called when this application becomes the foreground application.
Only the foreground application receives tracking data from the Leap Motion Controller. This function is only called when the controller object is in a connected state.
controller | The Controller object invoking this callback function. |
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inlinevirtual |
Called when this application loses the foreground focus.
Only the foreground application receives tracking data from the Leap Motion Controller. This function is only called when the controller object is in a connected state.
controller | The Controller object invoking this callback function. |
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inlinevirtual |
Called when a new frame of hand and finger tracking data is available.
Access the new frame data using the Controller::frame() function.
Note, the Controller skips any pending onFrame events while your onFrame handler executes. If your implementation takes too long to return, one or more frames can be skipped. The Controller still inserts the skipped frames into the frame history. You can access recent frames by setting the history parameter when calling the Controller::frame() function. You can determine if any pending onFrame events were skipped by comparing the ID of the most recent frame with the ID of the last received frame.
controller | The Controller object invoking this callback function. |
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inlinevirtual |
Called once, when this Listener object is newly added to a Controller.
controller | The Controller object invoking this callback function. |