#[repr(transparent)]
pub struct PadTemplate { /* private fields */ }
Expand description

Padtemplates describe the possible media types a pad or an elementfactory can handle. This allows for both inspection of handled types before loading the element plugin as well as identifying pads on elements that are not yet created (request or sometimes pads).

Pad and PadTemplates have Caps attached to it to describe the media type they are capable of dealing with. caps() or GST_PAD_TEMPLATE_CAPS() are used to get the caps of a padtemplate. It’s not possible to modify the caps of a padtemplate after creation.

PadTemplates have a PadPresence property which identifies the lifetime of the pad and that can be retrieved with GST_PAD_TEMPLATE_PRESENCE(). Also the direction of the pad can be retrieved from the PadTemplate with GST_PAD_TEMPLATE_DIRECTION().

The GST_PAD_TEMPLATE_NAME_TEMPLATE () is important for GST_PAD_REQUEST pads because it has to be used as the name in the ElementExtManual::request_pad_simple() call to instantiate a pad from this template.

Padtemplates can be created with new() or with gst_static_pad_template_get (), which creates a PadTemplate from a StaticPadTemplate that can be filled with the convenient GST_STATIC_PAD_TEMPLATE() macro.

A padtemplate can be used to create a pad (see Pad::from_template() or gst_pad_new_from_static_template ()) or to add to an element class (see gst_element_class_add_static_pad_template ()).

The following code example shows the code to create a pad from a padtemplate.

⚠️ The following code is in C ⚠️

  GstStaticPadTemplate my_template =
  GST_STATIC_PAD_TEMPLATE (
    "sink",          // the name of the pad
    GST_PAD_SINK,    // the direction of the pad
    GST_PAD_ALWAYS,  // when this pad will be present
    GST_STATIC_CAPS (        // the capabilities of the padtemplate
      "audio/x-raw, "
        "channels = (int) [ 1, 6 ]"
    )
  );
  void
  my_method (void)
  {
    GstPad *pad;
    pad = gst_pad_new_from_static_template (&my_template, "sink");
    ...
  }

The following example shows you how to add the padtemplate to an element class, this is usually done in the class_init of the class:

⚠️ The following code is in C ⚠️

  static void
  my_element_class_init (GstMyElementClass *klass)
  {
    GstElementClass *gstelement_class = GST_ELEMENT_CLASS (klass);

    gst_element_class_add_static_pad_template (gstelement_class, &my_template);
  }

Implements

GstObjectExt, glib::ObjectExt

Implementations

Creates a new pad template with a name according to the given template and with the given arguments.

name_template

the name template.

direction

the PadDirection of the template.

presence

the PadPresence of the pad.

caps

a Caps set for the template.

Returns

a new PadTemplate.

This is supported on crate feature v1_14 only.

Creates a new pad template with a name according to the given template and with the given arguments.

name_template

the name template.

direction

the PadDirection of the template.

presence

the PadPresence of the pad.

caps

a Caps set for the template.

pad_type

The GType of the pad to create

Returns

a new PadTemplate.

Gets the capabilities of the pad template.

Returns

the Caps of the pad template. Unref after usage.

This is supported on crate feature v1_18 only.

See set_documentation_caps().

Returns

The caps to document. For convenience, this will return caps() when no documentation caps were set.

Emit the pad-created signal for this template when created by this pad.

pad

the Pad that created it

This is supported on crate feature v1_18 only.

Certain elements will dynamically construct the caps of their pad templates. In order not to let environment-specific information into the documentation, element authors should use this method to expose “stable” caps to the reader.

caps

the documented capabilities

The direction of the pad described by the pad template.

This is supported on crate feature v1_14 only.

The type of the pad described by the pad template.

The name template of the pad template.

When the pad described by the pad template will become available.

This signal is fired when an element creates a pad from this template.

pad

the pad that was created.

This is supported on crate feature v1_14 only.

Converts a StaticPadTemplate into a PadTemplate with a type.

pad_template

the static pad template

pad_type

The GType of the pad to create

Returns

a new PadTemplate.

Trait Implementations

Returns a copy of the value. Read more

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This method returns an Ordering between self and other. Read more

Compares and returns the maximum of two values. Read more

Compares and returns the minimum of two values. Read more

Restrict a value to a certain interval. Read more

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

Returns the type identifier of Self.

Auto Trait Implementations

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Similar to Self::set_property but fails instead of panicking.

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Similar to Self::set_property but fails instead of panicking.

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🔬 This is a nightly-only experimental API. (toowned_clone_into)

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