qr code generator in asp.net c# GtkProgressBar in Font

Painting ECC200 in Font GtkProgressBar

The GtkAssistant example introduced another new widget called GtkProgressBar. Progress bars are a simple way to show how much of a process has been completed and is useful for processes that take a long time to handle. Progress bars give the user a visual cue that progress is being made, so they do not think the program has frozen.

New progress bars are created with gtk_progress_bar_new(). The implementation of GtkProgressBar was made a lot simpler with the release of GTK+ 2.0, so be careful when using the API documentation, because a number of the displayed functions and properties are depreciated. The two examples following show you how to correctly use the GtkProgressBar widget. There are two ways to use the GtkProgressBar widget. If you are sure of how much progress a process has made, you should use gtk_progress_bar_set_fraction() to set a discrete value. This function accepts values between 0.0 and 1.0, where 1.0 sets the progress bar as 100 percent complete. while (percent <= 100.0) { gchar *message = g_strdup_printf ("%.0f%% Complete", percent); gtk_progress_bar_set_fraction (progress, percent / 100.0); gtk_progress_bar_set_text (progress, message); while (gtk_events_pending ()) gtk_main_iteration (); g_usleep (500000); percent += 5.0; } You may also want to display text that can be used to complement the progress bar. In the preceding example, gtk_progress_bar_set_text() was used to display the percent complete statistic, which is superimposed on the progress bar widget. If you are not able to detect the progress of the process, you can use pulses. In the preceding example, gtk_progress_bar_pulse() was used to move the progress bar one step for every pending event that was processed. You can set the pulse step with gtk_progress_bar_set_pulse_step(). gtk_progress_bar_set_pulse_step (GTK_PROGRESS_BAR (bar), 0.1); while (gtk_events_pending ()) { gtk_main_iteration (); gtk_progress_bar_pulse (); } By setting the pulse step to 0.1, the progress bar will fill itself up in the first ten steps and clear itself out in the next ten. This process will continue for as long as you continue pulsing the progress bar.

There are times that you may want to skip to specific assistant pages if conditions are correct. For example, let us assume your application is creating a new project. Depending on the chosen language, you want to jump to either the third or fourth page. In this case, you will want to define your own GtkAssistantPageFunc function for forward motion.

You can use gtk_assistant_set_forward_page_func() to define a new page forward function for the assistant. By default, GTK+ will increment directly through the pages in order, one page at a time. By defining a new forward function, you can define the flow. void gtk_assistant_set_forward_page_func (GtkAssistant *assistant, GtkAssistantPageFunc page_func, gpointer data, GDestroyNotify destroy_func); For example, assistant_forward() is a simple GtkAssistantPageFunc implementation that moves from page two to either three or four depending on the condition returned by decide_next_page(). static gint assistant_forward (gint current_page, gpointer data) { gint next_page = 0; switch (current_page) { case 0: next_page = 1; break; case 1: next_page = (decide_next_page() 2 : 3); break; case 2: case 3: next_page = 4; break; default: next_page = -1; } return next_page; }

Note By returning -1 from a page forward function, the user will be presented with a critical error and

the assistant will not move to another page. The critical error message will tell the user that the page flow is broken.

In the assistant_forward() function, flow is changed based on the Boolean value returned by the fictional function decide_next_page(). In either case, the last page will be page 4. If the current page is not within bounds, -1 is returned, so an exception is thrown by GTK+.

While this GtkAssistant example is very simple, implementations of this widget can become very complex as they expand in number of pages. This widget could be re-created with a dialog, a GtkNotebook with hidden tabs, and a few buttons (I have had to do that very thing multiple times!), but it makes the process a lot easier.