ruby-****@sourc*****
ruby-****@sourc*****
2004年 2月 28日 (土) 03:00:42 JST
-------------------------
REMOTE_ADDR = 217.117.55.140
REMOTE_HOST =
URL = http://ruby-gnome2.sourceforge.jp/?tut-gst-bins-ghost-pads
-------------------------
= Ghost Pads
You can see from the following figure how a bin has no pads of its own. This is where "ghost pads" come into play.
{{image_left("bin-element-noghost.png")}}
{{br}}
A ghost pad is a pad from some element in the bin that has been promoted to the bin. This way, the bin also has a pad. The bin becomes just another element with a pad and you can then use the bin just like any other element. This is a very important feature for creating custom bins.
{{image_left("bin-element-ghost.png")}}
{{br}}
The above figure is a representation of a ghost pad. The sink pad of element one is now also a pad of the bin.
Ghost pads can actually be added to all Gst::Element objects and not just Gst::Bin objects. Use the following code example to add a ghost pad to a bin:
element = Gst::ElementFactory.make("mad")
bin = Gst::Bin.new
bin.add(element)
bin.add_ghost_pad(element.get_pad("sink"), "sink")
In the above example, the bin now also has a pad: the pad called 'sink' of the given element.
We can now, for example, link the source pad of a filesrc element to the bin with:
filesrc = Gst::ElementFactory.make("filesrc")
filesrc >> bin