EVENT (message data from ScreenEvent)

• Source: https://www.freebasic.net/wiki/wikka.php?wakka=KeyPgEvent
• Last revised: 2022-06-07

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Pre-defined structure (UDT) from fbgfx.bi used by Screenevent to return event data

Syntax

#include once "fbgfx.bi"
using fb
dim variable as Event

Description

Here we report the EVENT structure for clarity:

start GeSHi

Type EVENT Field = 1
    Type As Long
    Union
        Type
            scancode As Long
            ascii As Long
        End Type
        Type
            x As Long
            y As Long
            dx As Long
            dy As Long
        End Type
        button As Long
        z As Long
        w As Long
    End Union
End Type

end GeSHi

The Type field will contain the event type ID, while the remaining 4 integers will hold sensitive data to the event type.

Event types

The event type is identified by an ID number returned into the first integer of the event buffer (the .type field in the EVENT structure). Known event type IDs - and their values at time of writing - are:

• EVENT_KEY_PRESS (1) A key was pressed on the keyboard. The .scancode field contains the platform independent scancode value for the key; if the key has an ascii representation, it is held into the .ascii field, which otherwise has a value of 0.
• EVENT_KEY_RELEASE (2) A key was released on the keyboard. The .scancode and .ascii fields have the same meaning as with the EVENT_KEY_PRESS event.
• EVENT_KEY_REPEAT (3) A key is being held down repeatedly. The .scancode and .ascii fields have the same meaning as with the EVENT_KEY_PRESS event.
• EVENT_MOUSE_MOVE (4) The mouse was moved while it was on the program window. The .x and .y fields contain the new mouse position relative to the upper-left corner of the screen, while the .dx and .dy fields contain the motion deltas.
• EVENT_MOUSE_BUTTON_PRESS (5) One of the mouse buttons was pressed. The .button field has one bit set identifying the button that was pressed; bit 0 identifies the left mouse button, bit 1 the right mouse button and bit 2 the middle mouse button.
• EVENT_MOUSE_BUTTON_RELEASE (6) One of the mouse buttons was released. The .button field has the same meaning as with the EVENT_MOUSE_BUTTON_PRESS event.
• EVENT_MOUSE_DOUBLE_CLICK (7) One of the mouse buttons was double clicked. The .button field has the same meaning as with the EVENT_MOUSE_BUTTON_PRESS event.
• EVENT_MOUSE_WHEEL (8) The mouse wheel was used; the new wheel position is returned into the .z field.
• EVENT_MOUSE_ENTER (9) The mouse was moved into the program window.
• EVENT_MOUSE_EXIT (10) The mouse was moved out of the program window.
• EVENT_WINDOW_GOT_FOCUS (11) The program window has got focus.
• EVENT_WINDOW_LOST_FOCUS (12) The program window has lost focus.
• EVENT_WINDOW_CLOSE (13) The user attempted to close the program window.
• EVENT_MOUSE_HWHEEL (14) The horizontal mouse wheel was used; the new horizontal wheel position is returned into the .w field.

The fbgfx.bi header file contains a definition of the EVENT user data type, so it is not necessary to declare it manually.

Examples

See example at ScreenEvent.

Dialect Differences

• In lang fb, the structure and constants are stored in the FB Namespace. This is not the case in other dialects.

Differences from QB

• New to FreeBASIC

See also

• ScreenEvent
• Event Handling
• Keyboard scancodes
• Keyboard Input

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