The Gtk::ProgressBar is typically used to display the progress of a long running operation. It provides a visual clue that processing is underway. The Gtk::ProgressBar 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 Gtk::ProgressBar 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 set_fraction() periodically to update the progress bar.
When an application has no accurate way of knowing the amount of work to do, it can use the Gtk::ProgressBar 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 Gtk::ProgressBar. 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.
Constructor & Destructor Documentation
virtual Gtk::ProgressBar::~ProgressBar
(
)
[virtual]
Gtk::ProgressBar::ProgressBar
(
)
Member Function Documentation
double Gtk::ProgressBar::get_fraction
(
)
const
Returns the current fraction of the task that's been completed.
Indicates that some progress is made, but you don't know how much.
Causes the progress bar to enter "activity mode," where a block bounces back and forth. Each call to pulse() causes the block to move by a little bit (the amount of movement per pulse is determined by set_pulse_step()).
void Gtk::ProgressBar::set_fraction
(
double
fraction
)
Causes the progress bar to "fill in" the given fraction of the bar.
The fraction should be between 0.0 and 1.0, inclusive.