Re: Refreshing gtk window without any mouse/keyboard intervention

[Gus Koppel <gtk spamkiller bytechase cx>]

Nisha P Kurur wrote:

> We are trying to create a gtk application which should run without much of 
> manual intervention. Few buttons are placed in a row and each button has 
> an image at the top which changes to red on selection. This image changes 
> to green when the button goes out of selection. So the whole process has 
> to be done in a scan mode without any manual intervention.
>
> The problem with our code (attached with this mail) is that the events are 
> generated and the callback functions are called. But the window is not 
> refreshed properly. The window gets updated only when there is any
> mouse/keyboard movement.

1. using the sleep() function in a GUI application is very bad
   programming style by all means, even if taking place in a custom
   thread. It's a relict of shell programming. You should rather use
   gtk_timeout_add() or g_timeout_add(). Probably you can even do without
   multiple threads then, which may avoid some hard to find bugs in the
   future and makes debugging much easier. See:

http://developer.gnome.org/doc/API/2.0/gtk/gtk-General.html#gtk-timeout-add
http://developer.gnome.org/doc/API/2.0/glib/glib-The-Main-Event-Loop.html#g-timeout-add

2. you have to make sure that GTK+ can pass through its main loop for
   changes to be drawn. In a single-threaded application this would
   have to happen after your g_signal_emit_by_name() calls. See:

http://developer.gnome.org/doc/API/2.0/gtk/gtk-General.html#gtk-main-iteration-do

3. you probably know that the switch-case tree of your example is  
   bloated, i.e. contains much redundancy which could (and probably
   should) be avoided. Of 7 statements, 3 are completely identical
   and the other ones could be unified by simply using your "index"
   variable instead of distinct constants to pass to the respective
   functions. Add a little list of const strings for the xpm_label_box()
   call and you can do completely without a switch-case, that is, with
   only 1 instead of 9 blocks of that code.

Golden rule of programming: _never_ use the copy & paste feature of your
text editor for more than three or four lines of code, especially not
multiple times! Write sub functions (or in this case: just restructure a
code block) instead.