get_framegrabber_callbackT_get_framegrabber_callbackGetFramegrabberCallbackGetFramegrabberCallbackget_framegrabber_callback (Operator)
Name
get_framegrabber_callbackT_get_framegrabber_callbackGetFramegrabberCallbackGetFramegrabberCallbackget_framegrabber_callback — Query callback function of an image acquisition device.
Signature
Description
The operator get_framegrabber_callbackget_framegrabber_callbackGetFramegrabberCallbackGetFramegrabberCallbackget_framegrabber_callback queries a callback function
for the image acquisition device specified by AcqHandleAcqHandleAcqHandleacqHandleacq_handle. If the
callback function was registered via set_framegrabber_callbackset_framegrabber_callbackSetFramegrabberCallbackSetFramegrabberCallbackset_framegrabber_callback
before, CallbackFunctionCallbackFunctionCallbackFunctioncallbackFunctioncallback_function contains a pointer to it, otherwise
NULL. Furthermore, UserContextUserContextUserContextuserContextuser_context contains a pointer to the
user-specific context data that was set via
set_framegrabber_callbackset_framegrabber_callbackSetFramegrabberCallbackSetFramegrabberCallbackset_framegrabber_callback (or NULL).
With the parameter CallbackTypeCallbackTypeCallbackTypecallbackTypecallback_type, you can select different callback
types. Suggested values are:
- 'exception':
The image acquisition has raised an exception.
- 'exposure_end':
The exposure of the next image has been finished.
- 'exposure_start':
The exposure of the next image has been started.
- 'transfer_end':
A new image is ready to be fetched
by grab_image_asyncgrab_image_asyncGrabImageAsyncGrabImageAsyncgrab_image_async.
Depending on the functionality of the underlying API, additional values
for CallbackTypeCallbackTypeCallbackTypecallbackTypecallback_type are possible. All actually supported callback
types of a specific image acquisition device can be queried by
calling get_framegrabber_paramget_framegrabber_paramGetFramegrabberParamGetFramegrabberParamget_framegrabber_param with the parameter
'available_callback_types'. For more details see the
documentation of the specific image acquisition interface.
Attention
For a multithreaded application,
info_framegrabberinfo_framegrabberInfoFramegrabberInfoFramegrabberinfo_framegrabber, open_framegrabberopen_framegrabberOpenFramegrabberOpenFramegrabberopen_framegrabber, and
close_framegrabberclose_framegrabberCloseFramegrabberCloseFramegrabberclose_framegrabber are executed exclusively.
get_framegrabber_callbackget_framegrabber_callbackGetFramegrabberCallbackGetFramegrabberCallbackget_framegrabber_callback runs in parallel with all non-exclusive
operators inside and outside of this group.
Execution Information
- Multithreading type: reentrant (runs in parallel with non-exclusive operators).
- Multithreading scope: global (may be called from any thread).
- Processed without parallelization.
Parameters
AcqHandleAcqHandleAcqHandleacqHandleacq_handle (input_control) framegrabber → HFramegrabber, HTupleHHandleHTupleHtuple (handle) (IntPtr) (HHandle) (handle)
Handle of the acquisition device to be used.
CallbackTypeCallbackTypeCallbackTypecallbackTypecallback_type (input_control) string → HTuplestrHTupleHtuple (string) (string) (HString) (char*)
Callback type.
Default:
'transfer_end'
"transfer_end"
"transfer_end"
"transfer_end"
"transfer_end"
Suggested values:
'exception'"exception""exception""exception""exception", 'exposure_end'"exposure_end""exposure_end""exposure_end""exposure_end", 'exposure_start'"exposure_start""exposure_start""exposure_start""exposure_start", 'transfer_end'"transfer_end""transfer_end""transfer_end""transfer_end"
CallbackFunctionCallbackFunctionCallbackFunctioncallbackFunctioncallback_function (output_control) pointer → HTupleintHTupleHtuple (integer) (IntPtr) (Hlong) (Hlong)
Pointer to the callback function.
UserContextUserContextUserContextuserContextuser_context (output_control) pointer → HTupleintHTupleHtuple (integer) (IntPtr) (Hlong) (Hlong)
Pointer to user-specific context data.
Result
If the image acquisition device is open and the specified callback type
is supported, the operator get_framegrabber_callbackget_framegrabber_callbackGetFramegrabberCallbackGetFramegrabberCallbackget_framegrabber_callback returns the
value 2 (
H_MSG_TRUE)
. Otherwise an exception is raised.
Possible Predecessors
open_framegrabberopen_framegrabberOpenFramegrabberOpenFramegrabberopen_framegrabber,
set_framegrabber_callbackset_framegrabber_callbackSetFramegrabberCallbackSetFramegrabberCallbackset_framegrabber_callback
Possible Successors
grab_imagegrab_imageGrabImageGrabImagegrab_image,
grab_datagrab_dataGrabDataGrabDatagrab_data,
grab_image_startgrab_image_startGrabImageStartGrabImageStartgrab_image_start,
grab_image_asyncgrab_image_asyncGrabImageAsyncGrabImageAsyncgrab_image_async,
grab_data_asyncgrab_data_asyncGrabDataAsyncGrabDataAsyncgrab_data_async,
set_framegrabber_paramset_framegrabber_paramSetFramegrabberParamSetFramegrabberParamset_framegrabber_param,
close_framegrabberclose_framegrabberCloseFramegrabberCloseFramegrabberclose_framegrabber
See also
open_framegrabberopen_framegrabberOpenFramegrabberOpenFramegrabberopen_framegrabber,
info_framegrabberinfo_framegrabberInfoFramegrabberInfoFramegrabberinfo_framegrabber,
set_framegrabber_callbackset_framegrabber_callbackSetFramegrabberCallbackSetFramegrabberCallbackset_framegrabber_callback
Module
Foundation