MdispHookFunction

Board	Supported
Host System	Yes
V4L2	Yes
Clarity UHD	Yes
Concord PoE	No
GenTL	Yes
GevIQ	Yes
GigE Vision	Yes
Indio	No
Iris GTX	Yes
Radient eV-CL	Yes
Rapixo CL	Yes
Rapixo CoF	Yes
Rapixo CXP	Yes
USB3 Vision	Yes

Hook a function to a display event.

Syntax

void MdispHookFunction(
    AIL_ID                     DisplayId,       //out
    AIL_INT                    HookType,        //in
    AIL_DISP_HOOK_FUNCTION_PTR HookHandlerPtr,  //in
    void *                     UserDataPtr      //in-out
)

Description

This function allows you to attach or detach a user-defined function to a specified display event. Once a hook-handler function is defined and hooked to an event, it is automatically called when the event occurs.

You can hook more than one function to an event by making separate calls to MdispHookFunction for each function that you want to hook. Aurora Imaging Library automatically chains and keeps an internal list of all these hooked functions. When a function is hooked, this new function is added to the end of the list. When the event happens, all user-defined functions in the list will be executed in the same order that they were hooked to the event. You can also remove any function from the list; in this case, Aurora Imaging Library preserves the order of the remaining functions in the list.

Note that this function is not available on network displays.

Parameters

DisplayId (out, AIL_ID)

Specifies the identifier of the target display.

HookType (in, AIL_INT)

Specifies the display event type. This parameter can be set to the following:

For specifying the display event type

Value	Description
M_KEY_CHAR	Calls the hook-handler function each time the user presses a character key, while the mouse cursor is in the display.
M_KEY_DOWN	Calls the hook-handler function each time the user presses a keyboard key, while the mouse cursor is in the display.
M_KEY_UP	Calls the hook-handler function each time the user releases a keyboard key, while the mouse cursor is in the display.
M_MOUSE_LEFT_BUTTON_DOWN	Calls the hook-handler function each time the user clicks the left mouse button, while the mouse cursor is in the display.
M_MOUSE_LEFT_BUTTON_UP	Calls the hook-handler function each time the user releases the left mouse button, while the mouse cursor is in the display.
M_MOUSE_LEFT_DOUBLE_CLICK	Calls the hook-handler function each time the user double-clicks the left mouse button, while the mouse cursor is in the display.
M_MOUSE_MIDDLE_BUTTON_DOWN	Calls the hook-handler function each time the user clicks the middle mouse button, while the mouse cursor is in the display.
M_MOUSE_MIDDLE_BUTTON_UP	Calls the hook-handler function each time the user releases the middle mouse button, while the mouse cursor is in the display.
M_MOUSE_MOVE	Calls the hook-handler function each time the mouse cursor moves, while in the display.
M_MOUSE_RIGHT_BUTTON_DOWN	Calls the hook-handler function each time the user clicks the right mouse button, while the mouse cursor is in the display.
M_MOUSE_RIGHT_BUTTON_UP	Calls the hook-handler function each time the user releases the right mouse button, while the mouse cursor is in the display.
M_MOUSE_WHEEL	Calls the hook-handler function each time the user scrolls the mouse wheel (up or down), while the mouse cursor is in the display.

For detaching the hook-handler function

Value	Description
M_UNHOOK	Unhooks the specified function if hooked to the specified event. When you use M_UNHOOK, you must provide the same values for all the parameters as when you originally hooked the function.

HookHandlerPtr (in, AIL_DISP_HOOK_FUNCTION_PTR)

Specifies the address of the function that should be called when the specified event occurs. The hook-handler function, pointed to by HookHandlerPtr, must be declared as follows:

UserDataPtr *(in-out, void)

Specifies the address of the user data that you want to make available to the hook-handler function. This address is passed to the hook-handler function, through its UserDataPtr parameter, when the specified event occurs. Set this parameter to M_NULL if not used.