Base class for GtkHScale and GtkVScale.
A GtkScale is a widget that looks very like a
GtkScrollbar without the arrow buttons at either
end and with the ability to display the current value as text.
There are some issues with the value display, in that scrolling-aware
container widgets will not allow their child's
GtkAdjustment to be overwritten, which means that
the GtkScale cannot have focus unless it takes
the values given by the container to the scrollable widget. This in turn
misconfigures the display area, which is calculated with regard to
the upper value of the associated adjustment object. When a container
sets an adjustment, each value is 0 at the start, and the later values
are calculated on the fly after the widgets have been drawn.
Although it is possible to use the GtkWidget
method queue_resize() to force
the text area to resize according to the width of the new adjustment
values, the widget does not fully redraw unless it has a configure event
- that is, you need to manually resize it and then restore it.
For all these reasons, it is unadvisable to use the draw-value feature
where the GtkScale is associated with a
Signal which allows the display value of the scale to be changed.