Table of Contents
gtkmm has various widgets that can be visually adjusted using the mouse or the keyboard, such as the Range widgets (described
in the Range Widgets section).
There are also a few widgets that display some adjustable
part of a larger area, such as the
Viewport widget. These widgets have Gtk::Adjustment
objects that express this common part of their API.
So that applications can react to changes, for instance when a user moves a scrollbar, Gtk::Adjustment
has a
changed
signal. You can then use the get_changed()
method to discover the new value.
The Gtk::Adjustment
constructor is as follows:
Gtk::Adjustment(float value, float lower, float upper, float step_increment = 1, float page_increment = 10, float page_size = 0);
The value
argument is the initial value of the adjustment, usually corresponding to the topmost or leftmost position
of an adjustable widget. The lower
and upper
arguments specifies the possible range of values which the adjustment can hold. The step_increment
argument
specifies the smaller of the two increments by which the user can
change the value, while the page_increment
is the larger one.
The page_size
argument usually corresponds somehow to the visible
area of a panning widget. The upper
argument is used to represent
the bottom most or right most coordinate in a panning widget's
child.
TODO: Investigate the upper argument properly. There was some unclear stuff about it not always being the upper value.