calling gtk_widget_queue_draw from another thread

[Horst Löffel <bionicspoon web de>]

Hi,

I'm currently working on a library that uses GTK to open multiple 
windows for drawing operations. The library will be used in a console 
application as a plugin for graphical output. It has to run on win64 and 
linux.

Because the program acts as a plugin i have to run gtk_main in it's own 
thread. But drawing operations will come from another thread which i 
call "main" thread. So my solution was to share a cairo surface between 
the main thread and the GTK thread. The redrawing than just happens in 
the draw event callback of the GtkWidget, where i will just draw the 
cairo surface.

I read in the api documentation that 'gdk_threads_enter/leave' is 
deprecated and we should use 'g_idle_add' instead.
So everytime i want the widget to update it's contents i pack a 
'gtk_widget_queue_draw' into an idle function. It works but I'm 
basically flooding the GTK event loop with tons of 'g_idle_add + 
queue_draw'.

It works surprisingly well on linux though. All the events seem to be 
handled very quickly. But on windows the graphic updates are very slow 
and jumpy. I think the windows version can't handle all the 
'g_idle_adds' well enough.

I am wondering if there is a better solution to my problem.


Horst