# Module Tk

    module Tk: sig .. end

Basic functions and types for LablTk

###### Initialization and termination

    val openTk : ?display:string -> ?clas:string -> unit -> Widget.toplevel Widget.widget

Initialize LablTk and open a toplevel window. `display` is described according to the X11 conventions. `clas` is used for the X11 resource mechanism.

    val mainLoop : unit -> unit

Start the main event loop

    val closeTk : unit -> unit

Quit the main loop and close all open windows.

    val destroy : 'a Widget.widget -> unit

Destroy an individual widget.

###### Application wide commands

    val update : unit -> unit

Synchronize display with internal state.

    val appname_get : unit -> string

    val appname_set : string -> unit

Get or set the application name.

###### Dimensions

    type units = [ `Cm of float | `In of float | `Mm of float | `Pix of int | `Pt of float ]

    val pixels : units -> int

Converts various on-screen units to pixels, respective to the default display. Available units are pixels, centimeters, inches, millimeters and points

###### Widget layout commands

    type anchor = [ `Center | `E | `N | `Ne | `Nw | `S | `Se | `Sw | `W ]

    type fillMode = [ `Both | `None | `X | `Y ]

    type side = [ `Bottom | `Left | `Right | `Top ]

    val pack : ?after:'a Widget.widget ->
           ?anchor:anchor ->
           ?before:'b Widget.widget ->
           ?expand:bool ->
           ?fill:fillMode ->
           ?inside:'c Widget.widget ->
           ?ipadx:int ->
           ?ipady:int ->
           ?padx:int -> ?pady:int -> ?side:side -> 'd Widget.widget list -> unit

Pack a widget inside its parent, using the standard layout engine.

    val grid : ?column:int ->
           ?columnspan:int ->
           ?inside:'a Widget.widget ->
           ?ipadx:int ->
           ?ipady:int ->
           ?padx:int ->
           ?pady:int ->
           ?row:int -> ?rowspan:int -> ?sticky:string -> 'b Widget.widget list -> unit

Pack a widget inside its parent, using the grid layout engine.

    type borderMode = [ `Ignore | `Inside | `Outside ]

    val place : ?anchor:anchor ->
           ?bordermode:borderMode ->
           ?height:int ->
           ?inside:'a Widget.widget ->
           ?relheight:float ->
           ?relwidth:float ->
           ?relx:float ->
           ?rely:float -> ?width:int -> ?x:int -> ?y:int -> 'b Widget.widget -> unit

Pack a widget inside its parent, at absolute coordinates.

    val raise_window : ?above:'a Widget.widget -> 'b Widget.widget -> unit

    val lower_window : ?below:'a Widget.widget -> 'b Widget.widget -> unit

Raise or lower the window associated to a widget.

###### Event handling

    type modifier = [ `Alt
           | `Button1
           | `Button2
           | `Button3
           | `Button4
           | `Button5
           | `Control
           | `Double
           | `Lock
           | `Meta
           | `Mod1
           | `Mod2
           | `Mod3
           | `Mod4
           | `Mod5
           | `Shift
           | `Triple ]

    type event = [ `ButtonPress
           | `ButtonPressDetail of int
           | `ButtonRelease
           | `ButtonReleaseDetail of int
           | `Circulate
           | `ColorMap
           | `Configure
           | `Destroy
           | `Enter
           | `Expose
           | `FocusIn
           | `FocusOut
           | `Gravity
           | `KeyPress
           | `KeyPressDetail of string
           | `KeyRelease
           | `KeyReleaseDetail of string
           | `Leave
           | `Map
           | `Modified of modifier list * event
           | `Motion
           | `Property
           | `Reparent
           | `Unmap
           | `Visibility ]

An event can be either a basic X event, or modified by a key or mouse modifier.
`type ``eventInfo = {`

`` | `mutable ev_Above : `int`;`
`` | `mutable ev_ButtonNumber : `int`;`
`` | `mutable ev_Count : `int`;`
`` | `mutable ev_Detail : `string`;`
`` | `mutable ev_Focus : `bool`;`
`` | `mutable ev_Height : `int`;`
`` | `mutable ev_KeyCode : `int`;`
`` | `mutable ev_Mode : `string`;`
`` | `mutable ev_OverrideRedirect : `bool`;`
`` | `mutable ev_Place : `string`;`
`` | `mutable ev_State : `string`;`
`` | `mutable ev_Time : `int`;`
`` | `mutable ev_Width : `int`;`
`` | `mutable ev_MouseX : `int`;`
`` | `mutable ev_MouseY : `int`;`
`` | `mutable ev_Char : `string`;`
`` | `mutable ev_BorderWidth : `int`;`
`` | `mutable ev_SendEvent : `bool`;`
`` | `mutable ev_KeySymString : `string`;`
`` | `mutable ev_KeySymInt : `int`;`
`` | `mutable ev_RootWindow : `int`;`
`` | `mutable ev_SubWindow : `int`;`
`` | `mutable ev_Type : `int`;`
`` | `mutable ev_Widget : `Widget.any Widget.widget`;`
`` | `mutable ev_RootX : `int`;`
`` | `mutable ev_RootY : `int`;`

}
Event related information accessible in callbacks.

    type eventField = [ `Above
           | `BorderWidth
           | `ButtonNumber
           | `Char
           | `Count
           | `Detail
           | `Focus
           | `Height
           | `KeyCode
           | `KeySymInt
           | `KeySymString
           | `Mode
           | `MouseX
           | `MouseY
           | `OverrideRedirect
           | `Place
           | `RootWindow
           | `RootX
           | `RootY
           | `SendEvent
           | `State
           | `SubWindow
           | `Time
           | `Type
           | `Widget
           | `Width ]

In order to access the above event information, one has to pass a list of required event fields to the `bind` function.

    val bind : events:event list ->
           ?extend:bool ->
           ?breakable:bool ->
           ?fields:eventField list ->
           ?action:(eventInfo -> unit) -> 'a Widget.widget -> unit

Bind a succession of `events` on a widget to an `action`. If `extend` is true then then binding is added after existing ones, otherwise it replaces them. `breakable` should be true when `break` is to be called inside the action. `action` is called with the `fields` required set in an `eventInfo` structure. Other fields should not be accessed. If `action` is omitted then existing bindings are removed.

    val bind_class : events:event list ->
           ?extend:bool ->
           ?breakable:bool ->
           ?fields:eventField list ->
           ?action:(eventInfo -> unit) -> ?on:'a Widget.widget -> string -> unit

Same thing for all widgets of a given class. If a widget is given with label `~on:`, the binding will be removed as soon as it is destroyed.

    val bind_tag : events:event list ->
           ?extend:bool ->
           ?breakable:bool ->
           ?fields:eventField list ->
           ?action:(eventInfo -> unit) -> ?on:'a Widget.widget -> string -> unit

Same thing for all widgets having a given tag

    val break : unit -> unit

Used inside a bound action, do not call other actions after this one. This is only possible if this action was bound with `~breakable:true`.