Tutorials > lablgtk2 tutorial > Container widgets > View ports

View ports

It is unlikely that you will ever need to use the Viewport widget directly. You are much more likely to use the Scrolled Window widget which itself uses the Viewport.

A viewport widget allows you to place a larger widget within it such that you can view a part of it at a time. It uses Adjustments to define the area that is currently in view.

A Viewport is created with the function GBin.viewport

val GBin.viewport :
	?hadjustment:GData.adjustment ->
	?vadjustment:GData.adjustment ->
	?shadow_type:Gtk.Tags.shadow_type ->
	?border_width:int ->
	?width:int ->
	?height:int ->
	?packing:(GObj.widget -> unit) ->
	?show:bool -> unit -> viewport

As you can see you can specify the horizontal and vertical Adjustments that the widget is to use when you create the widget. It will create its own if you don’t pass the arguments.

You can get and set the adjustments after the widget has been created using the following four functions:

method hadjustment : GData.adjustment
method vadjustment : GData.adjustment
method set_hadjustment : GData.adjustment -> unit
method set_vadjustment : GData.adjustment -> unit

The other viewport function is used to alter its appearance:

method set_shadow_type : Gtk.Tags.shadow_type -> unit

Possible values for the Gtk.Tags.shadow_type parameter are:

  `NONE,
  `IN,
  `OUT,
  `ETCHED_IN,
  `ETCHED_OUT