Python: How to convert GTK2 DrawingArea "expose_event" action into GTK3 "draw" action?

Development
,
1

I have existing Python code which was written for GTK2.

A dynamically created image is kept and modified in a “GdkPixbuf” object. Whenever it changed “queue_draw()” is called.

So far a “expose_event” action handler then did the actual display which no longer works with GTK3.

My first guess is that I have to replace “expose_event” with “draw” to bring my GdkPixbuf to display. So far the pixmap is drawn with:

obj.window.draw_pixbuf(obj.style.fg_gc[Gtk.StateType.NORMAL], self.preview_pixmap, 0, 0, 0, 0)

Where “obj” is the reference to the “DrawingArea” element.

This worked for GTK2 but I completely fail to adapt this to GTK3. If I’m right then the second argument to my “draw” handler will be directly the cairo surface but how do I get my pixbuf onto the cairo surface?

Thank you very much in advance.

2

Hi,

Don’t call draw() yourself.
Gtk will call it for you (when it needs to show something or after you call queue_draw()), and will provide the cairo context.

3

For drawing the pixbuf, look at Gdk.cairo_set_source_pixbuf :

def draw(cairo_context):
    Gdk.cairo_set_source_pixbuf(cairo_context, pixbuf, 0, 0)
    cairo_context.paint()
    return True