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.