set_drawing_object_callbackT_set_drawing_object_callbackSetDrawingObjectCallbackSetDrawingObjectCallback (Operator)

Name

set_drawing_object_callbackT_set_drawing_object_callbackSetDrawingObjectCallbackSetDrawingObjectCallback — Add a callback function to a drawing object.

Signature

Description

set_drawing_object_callbackset_drawing_object_callbackSetDrawingObjectCallbackSetDrawingObjectCallbackSetDrawingObjectCallback adds the callback function CallbackFunctionCallbackFunctionCallbackFunctionCallbackFunctioncallbackFunction to be called on the event(s) defined in DrawObjectEventDrawObjectEventDrawObjectEventDrawObjectEventdrawObjectEvent to the drawing object DrawHandleDrawHandleDrawHandleDrawHandledrawHandle. An event is an action, i.e., a user interaction with the mouse or a call to a HALCON operator, e.g., attach_drawing_object_to_windowattach_drawing_object_to_windowAttachDrawingObjectToWindowAttachDrawingObjectToWindowAttachDrawingObjectToWindow), that changes the current state of a given drawing object. The operator set_drawing_object_callbackset_drawing_object_callbackSetDrawingObjectCallbackSetDrawingObjectCallbackSetDrawingObjectCallback allows to define how to react to those events.

The following predefined events are available:

'on_attach'"on_attach""on_attach""on_attach""on_attach"

The corresponding callback will be called right after the object has been attached to the HALCON window and is ready for interaction.

'on_detach'"on_detach""on_detach""on_detach""on_detach"

The corresponding callback will be called right after the object has been detached from the window and is no longer available for interaction.

'on_drag'"on_drag""on_drag""on_drag""on_drag"

The corresponding callback will be called right after the object has been dragged with mouse interaction.

'on_resize'"on_resize""on_resize""on_resize""on_resize"

The corresponding callback will be called right after the object has been resized with mouse interaction.

'on_select'"on_select""on_select""on_select""on_select"

The corresponding callback will be called right after the object has been selected with mouse interaction.

It is possible to specify a particular callback for each desired event. Then the input parameters DrawObjectEventDrawObjectEventDrawObjectEventDrawObjectEventdrawObjectEvent and CallbackFunctionCallbackFunctionCallbackFunctionCallbackFunctioncallbackFunction must have the same length. It is also possible to use the same callback for different events. Then DrawObjectEventDrawObjectEventDrawObjectEventDrawObjectEventdrawObjectEvent has an arbitrary length and CallbackFunctionCallbackFunctionCallbackFunctionCallbackFunctioncallbackFunction contains one single value.

The callback is an integer of long type containing a pointer to a C function with the following signature:

Herror HDrawObjCallback(long DrawHandle, long WindowHandle, char *type)

On Windows systems, the __stdcall naming convention is used:

Herror (__stdcall HDrawObjCallback)(long DrawHandle, long WindowHandle, char* type)

The first parameter of the callback function contains the handle to the draw object that generated the event, the second one contains the handle of the window where the interaction took place. Finally, the third parameter indicates which event occurred.

Attention

No graphical operator should be called within the callback, like for example disp_objdisp_objDispObjDispObjDispObj, for otherwise a deadlock may occur.

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

Result

set_drawing_object_callbackset_drawing_object_callbackSetDrawingObjectCallbackSetDrawingObjectCallbackSetDrawingObjectCallback returns 2 (H_MSG_TRUE), if DrawHandleDrawHandleDrawHandleDrawHandledrawHandle is valid. Otherwise an exception is raised.

Possible Predecessors

attach_drawing_object_to_windowattach_drawing_object_to_windowAttachDrawingObjectToWindowAttachDrawingObjectToWindowAttachDrawingObjectToWindow

Possible Successors

close_windowclose_windowCloseWindowCloseWindowCloseWindow, clear_drawing_objectclear_drawing_objectClearDrawingObjectClearDrawingObjectClearDrawingObject, detach_drawing_object_from_windowdetach_drawing_object_from_windowDetachDrawingObjectFromWindowDetachDrawingObjectFromWindowDetachDrawingObjectFromWindow, get_drawing_object_iconicget_drawing_object_iconicGetDrawingObjectIconicGetDrawingObjectIconicGetDrawingObjectIconic, get_drawing_object_paramsget_drawing_object_paramsGetDrawingObjectParamsGetDrawingObjectParamsGetDrawingObjectParams

See also

create_drawing_object_rectangle1create_drawing_object_rectangle1CreateDrawingObjectRectangle1CreateDrawingObjectRectangle1CreateDrawingObjectRectangle1, attach_drawing_object_to_windowattach_drawing_object_to_windowAttachDrawingObjectToWindowAttachDrawingObjectToWindowAttachDrawingObjectToWindow, detach_drawing_object_from_windowdetach_drawing_object_from_windowDetachDrawingObjectFromWindowDetachDrawingObjectFromWindowDetachDrawingObjectFromWindow

Module

Foundation