A widget for displaying incremental or continuous progress.
The GtkProgressBar is typically used to display the progress of a long
running operation. It provides a visual clue that processing is underway.
The GtkProgressBar can be used in two different modes: percentage mode
and activity mode.
When an application can determine how much work needs to take place
(e.g. read a fixed number of bytes from a file) and can monitor its
progress, it can use the GtkProgressBar in percentage mode and the user
sees a growing bar indicating the percentage of the work that has been
completed. In this mode, the application is required to call
to update the progress bar.
When an application has no accurate way of knowing the amount of work
to do, it can use the GtkProgressBar in activity mode, which shows
activity by a block moving back and forth within the progress area.
In this mode, the application is required to call
pulse() perodically to update
the progress bar.
There is quite a bit of flexibility provided to control the appearance
of the GtkProgressBar. Functions are provided to control the orientation
of the bar, optional text can be displayed along with the bar,
and the step size used in activity mode can be set.
The progress bar is not updated after calling
set_fraction() , but in the
main loop. This means that, in a long running operation, you need
to let the UI update itself by using
Creates a new progress bar.