Re: GTK3+ (3.14) drawing area on scrolledwindow. Bug?

[Emmanuele Bassi <ebassi gmail com>]

Hi;

On 6 May 2015 at 10:35, rsm <rsm imap cc> wrote:
>         for i in range(3):
>             da=Gtk.DrawingArea()
>             da.connect("draw", self.draw, [0.3, 0.4, 0.6], da)
>             da.set_size_request(100,100)
>             box.add(da)
>
>         sw.add(vp)
>         vp.add(box)
>         self.add(sw)
>         self.show_all()
>
>     def draw(self, widget, event, color, da):
>         cr = widget.get_property('window').cairo_create()
>         cr.rectangle(0, 0, 100, 100)
>         cr.set_source_rgb(color[0], color[1], color[2])
>         cr.fill()

The implementation of the GtkWidget::draw signal handler is wrong.

The draw signal provides you with the Cairo context to draw on; you do
not need (and actually you mustn't) use Gdk.Window.cairo_create().

You're also passing the drawing area widget, but that's the widget
that emits the signal, so it's pointless.

A valid draw signal implementation is:

  def draw(self, widget, cr):
      cr.rectangle(x, y, width, height)
      cr.set_source_rgb(red, green, blue)
      cr.fill()
      return True

You should read the API reference for GTK+ 3.x:

  https://developer.gnome.org/gtk/stable

as well as the Python API reference:

  http://lazka.github.io/pgi-docs/#Gtk-3.0

Ciao,
 Emmanuele.

-- 
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