Re: Actor signals

["Patrick Shirkey" <pshirkey boosthardware com>]

On Tue, October 30, 2012 12:47 pm, Lionel Landwerlin wrote:
> On 30/10/12 01:37, Patrick Shirkey wrote:
> > On Tue, October 30, 2012 12:27 pm, Lionel Landwerlin wrote:
> > > On 30/10/12 01:19, Patrick Shirkey wrote:
> > > > Thanks for your advice.
> > > >
> > > > This is the pick method:
> > > >
> > > >       def do_pick (self, pick_color):
> > > >           if self.should_pick_paint() == False:
> > > >               return
> > > >
> > > >           box = self.get_allocation_box()
> > > >           self.__draw_shape(box.x2 - box.x1, box.y2 - box.y1,
> > > > pick_color)
> > > >
> > > >
> > > >
> > > > There's not much to it so I am not sure why it is doing something
> > > > weird
> > > > or
> > > > how to fix it.
> > > Are you sure the __draw_shape() method doesn't alterate the picking
> > > color when drawing? (opacity? mask?)
> > The opacity is being explicitly set in the button-press-event handler.
> >
> >      if(status == 0): # button-press-event
> >          opacity = 200
> >      else: # button-release-event/button-leave-event
> >          opacity = 255
> >
> >      set_opacity(opacity)
> >
> >
> > The __draw_shape function doesn't appear to have anything that would
> > cause
> > trouble. Also the code works for the top layer but not the bottom layer.
> > The issue appears to be that the id of the actor is not found for the
> > bottom layer but I am not sure why it would be unable to find it's own
> > id
> > especially when the top layer doesn't have this problem.
> >
> >
> > Here's the __draw_shape methods:
> >
> >      def do_draw_shape(self, width, height):
> >          pass
> >
> >      def __draw_shape(self, width, height, color=None, texture=None):
> >          tmp_alpha = self.get_paint_opacity() * color.alpha / 255
> >          if texture:
> >              Cogl.set_source_texture(texture)
> >          else:
> >              Cogl.set_source_color4ub(color.red, color.green,
> > color.blue,
> > tmp_alpha)
> >          self.do_draw_shape(width, height)
> >          Cogl.path_fill()
>
> Well that's the problem.
> When the pick function is called, it should ONLY draw with given color.
> Nothing else.
> No opacity.
>
> Clutter does picking (aka finding the actor underneath you pointer) by
> rendering each object of the scene with a different color.
> Then reading the value of the color at a given position in the rendered
> scene.
>
> If you change the opacity when doing the picking you're using a color
> that isn't known by Clutter, therefore leading to the warning you've seen.
>
> You should add an opacity argument to __draw_shape() and pass :
>
> self.get_paint_opacity() * color.alpha / 255
>
> when called from do_draw_shape() and pass
>
> color.alpha
>
> when called from do_pick()
>
> -Lionel

Thanks for that insight.


For reference this code is working for me now:

----

    def do_draw_shape(self, width, height):
        pass

    def __draw_shape(self, width, height, color=None, opacity=None,
texture=None):
        if texture:
            Cogl.set_source_texture(texture)
        else:
            Cogl.set_source_color4ub(color.red, color.green, color.blue,
opacity)
        self.do_draw_shape(width, height)
        Cogl.path_fill()

    def do_paint (self):
        box = self.get_allocation_box()
        if self._texture:
            self.__draw_shape(box.x2 - box.x1, box.y2 - box.y1,
self._color, texture = self._texture.get_cogl_texture())
        else:
            self._color.alpha = self.get_paint_opacity()
            self.__draw_shape(box.x2 - box.x1, box.y2 - box.y1, color =
self._color, opacity = self._color.alpha)

    def do_pick (self, pick_color):
        if self.should_pick_paint() == False:
            return

        box = self.get_allocation_box()
        self.__draw_shape(box.x2 - box.x1, box.y2 - box.y1, pick_color,
pick_color.alpha)

----


--
Patrick Shirkey
Boost Hardware Ltd