Cropping Capability

Functions
XN_C_API XnStatus XN_C_DECL	xnSetCropping (XnNodeHandle hInstance, const XnCropping *pCropping)
XN_C_API XnStatus XN_C_DECL	xnGetCropping (XnNodeHandle hInstance, XnCropping *pCropping)
XN_C_API XnStatus XN_C_DECL	xnRegisterToCroppingChange (XnNodeHandle hInstance, XnStateChangedHandler handler, void *pCookie, XnCallbackHandle *phCallback)
XN_C_API void XN_C_DECL	xnUnregisterFromCroppingChange (XnNodeHandle hInstance, XnCallbackHandle hCallback)

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Detailed Description

The Cropping capability (XN_CAPABILITY_CROPPING) allows a Map Generator to output a selected area of the frame instead of the entire frame. When cropping is turned on, the data buffer looks just like resolution is smaller, meaning data is packed. For example if the MapGenerator is working in VGA resolution (640x480) and the application chose a cropping of 300x200, then after first 300 pixels the next pixel row begins. Pixels outside the cropping area are not returned in the buffer (and not just being blacked out). This is very useful for performance boost.

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Function Documentation

XN_C_API XnStatus XN_C_DECL xnGetCropping	(	XnNodeHandle	hInstance,
		XnCropping *	pCropping
	)

Gets current cropping configuration.

Parameters:

hInstance	[in] A handle to the instance.
pCropping	[out] Current cropping configuration.

Returns:

XN_STATUS_INVALID_OPERATION if this production node does not support the Cropping capability.

XN_C_API XnStatus XN_C_DECL xnRegisterToCroppingChange	(	XnNodeHandle	hInstance,
		XnStateChangedHandler	handler,
		void *	pCookie,
		XnCallbackHandle *	phCallback
	)

Registers a callback function to cropping changes.

Parameters:

hInstance	[in] A handle to the instance.
handler	[in] A pointer to a function that will be called when cropping changes.
pCookie	[in] A user cookie that will be passed to the callback function.
phCallback	[out] Optional. Will be filled with a handle to be passed to xnUnregisterFromCroppingChange().

XN_C_API XnStatus XN_C_DECL xnSetCropping	(	XnNodeHandle	hInstance,
		const XnCropping *	pCropping
	)

Sets the cropping.

Parameters:

hInstance	[in] A handle to the instance.
pCropping	[in] The cropping configuration to be set.

Returns:

XN_STATUS_INVALID_OPERATION if this production node does not support the Cropping capability.

XN_C_API void XN_C_DECL xnUnregisterFromCroppingChange	(	XnNodeHandle	hInstance,
		XnCallbackHandle	hCallback
	)

Unregisters a callback function which was registered using xnRegisterToCroppingChange().

Parameters:

hInstance	[in] A handle to the instance.
hCallback	[in] The handle to the callback returned from xnRegisterToCroppingChange().