Struct gstreamer::PadTemplate

#[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);
  }

Properties

`caps`

The capabilities of the pad described by the pad template.

Readable | Writeable | Construct Only

`direction`

The direction of the pad described by the pad template.

Readable | Writeable | Construct Only

`gtype`

The type of the pad described by the pad template.

Readable | Writeable | Construct Only

`name-template`

The name template of the pad template.

Readable | Writeable | Construct Only

`presence`

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

Readable | Writeable | Construct Only

Object

`name`

Readable | Writeable | Construct

`parent`

The parent of the object. Please note, that when changing the ‘parent’ property, we don’t emit notify and deep-notify signals due to locking issues. In some cases one can use element-added or element-removed signals on the parent to achieve a similar effect.

Readable | Writeable

Signals

`pad-created`

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

Object

`deep-notify`

The deep notify signal is used to be notified of property changes. It is typically attached to the toplevel bin to receive notifications from all the elements contained in that bin.

Detailed

Implements

GstObjectExt, glib::ObjectExt

Implementations§

impl PadTemplate

pub fn new(
    name_template: &str,
    direction: PadDirection,
    presence: PadPresence,
    caps: &Caps
) -> Result<PadTemplate, BoolError>

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.

pub fn with_gtype(
    name_template: &str,
    direction: PadDirection,
    presence: PadPresence,
    caps: &Caps,
    pad_type: Type
) -> Result<PadTemplate, BoolError>

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.

pub fn pad_created(&self, pad: &impl IsA<Pad>)

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

`pad`

the Pad that created it

pub fn connect_pad_created<F: Fn(&Self, &Pad) + Send + Sync + 'static>(
&self,
f: F
) -> SignalHandlerId

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

`pad`

the pad that was created.

impl PadTemplate

pub fn from_static_pad_template_with_gtype(
pad_template: &StaticPadTemplate,
pad_type: Type
) -> Result<PadTemplate, BoolError>

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.

pub fn caps(&self) -> &Caps

Gets the capabilities of the pad template.

Returns

the Caps of the pad template. Unref after usage.

pub fn documentation_caps(&self) -> &Caps

Available on crate feature v1_18 only.

See [set_documentation_caps()][Self::set_documentation_caps()].

Returns

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

pub fn direction(&self) -> PadDirection

The direction of the pad described by the pad template.

pub fn gtype(&self) -> Type

The type of the pad described by the pad template.

pub fn name_template(&self) -> &str

The name template of the pad template.

pub fn presence(&self) -> PadPresence

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

pub fn builder<'a>(
    name_template: &'a str,
    direction: PadDirection,
    presence: PadPresence,
    caps: &'a Caps
) -> PadTemplateBuilder<'a>

Trait Implementations§

impl Clone for PadTemplate

fn clone(&self) -> Self

Returns a copy of the value. Read more

1.0.0 · source§

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more

impl Debug for PadTemplate

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

impl HasParamSpec for PadTemplate

type ParamSpec = ParamSpecObject

type SetValue = PadTemplate

Preferred value to be used as setter for the associated ParamSpec.

type BuilderFn = fn(_: &str) -> ParamSpecObjectBuilder<'_, PadTemplate>

fn param_spec_builder() -> Self::BuilderFn

impl Hash for PadTemplate

fn hash<H>(&self, state: &mut H)where
H: Hasher,

Feeds this value into the given Hasher. Read more

1.3.0 · source§

fn hash_slice<H>(data: &[Self], state: &mut H)where
H: Hasher,
Self: Sized,

Feeds a slice of this type into the given Hasher. Read more

impl Ord for PadTemplate

fn cmp(&self, other: &Self) -> Ordering

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

1.21.0 · source§

fn max(self, other: Self) -> Selfwhere
Self: Sized,

Compares and returns the maximum of two values. Read more

1.21.0 · source§

fn min(self, other: Self) -> Selfwhere
Self: Sized,

Compares and returns the minimum of two values. Read more

1.50.0 · source§

fn clamp(self, min: Self, max: Self) -> Selfwhere
Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval. Read more

impl ParentClassIs for PadTemplate

type Parent = Object

impl<OT: ObjectType> PartialEq<OT> for PadTemplate

fn eq(&self, other: &OT) -> bool

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

1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<OT: ObjectType> PartialOrd<OT> for PadTemplate

fn partial_cmp(&self, other: &OT) -> Option<Ordering>

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

1.0.0 · source§

fn lt(&self, other: &Rhs) -> bool

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

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fn le(&self, other: &Rhs) -> bool

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

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fn gt(&self, other: &Rhs) -> bool

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

1.0.0 · source§

fn ge(&self, other: &Rhs) -> bool

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

impl StaticType for PadTemplate

fn static_type() -> Type

Returns the type identifier of Self.

impl Eq for PadTemplate

impl IsA<Object> for PadTemplate

impl Send for PadTemplate

impl Sync for PadTemplate

Auto Trait Implementations§

impl RefUnwindSafe for PadTemplate

impl Unpin for PadTemplate

impl UnwindSafe for PadTemplate

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impl<T> Any for Twhere
T: 'static + ?Sized,

fn type_id(&self) -> TypeId

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T: ?Sized,

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Mutably borrows from an owned value. Read more

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Upcasts an object to a reference of its superclass or interface T. Read more

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Calls U::from(self).

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Sets the property property_name of the object to value value. Read more

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Sets the property property_name of the object to value value. Read more

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Sets multiple properties of the object at once. Read more

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Sets multiple properties of the object at once. Read more

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Check if the object has a property property_name of the given type_. Read more

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Get the type of the property property_name of this object. Read more

fn find_property(&self, property_name: &str) -> Option<ParamSpec>

Get the ParamSpec of the property property_name of this object.

fn list_properties(&self) -> PtrSlice<ParamSpec>

Return all ParamSpec of the properties of this object.

fn freeze_notify(&self) -> PropertyNotificationFreezeGuard

Freeze all property notifications until the return guard object is dropped. Read more

unsafe fn set_qdata<QD>(&self, key: Quark, value: QD)where
QD: 'static,

Set arbitrary data on this object with the given key. Read more

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QD: 'static,

Return previously set arbitrary data of this object with the given key. Read more

unsafe fn steal_qdata<QD>(&self, key: Quark) -> Option<QD>where
QD: 'static,

Retrieve previously set arbitrary data of this object with the given key. Read more

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QD: 'static,

Set arbitrary data on this object with the given key. Read more

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QD: 'static,

Return previously set arbitrary data of this object with the given key. Read more

unsafe fn steal_data<QD>(&self, key: &str) -> Option<QD>where
QD: 'static,

Retrieve previously set arbitrary data of this object with the given key. Read more

fn block_signal(&self, handler_id: &SignalHandlerId)

Block a given signal handler. Read more

fn unblock_signal(&self, handler_id: &SignalHandlerId)

Unblock a given signal handler.

fn stop_signal_emission(&self, signal_id: SignalId, detail: Option<Quark>)

Stop emission of the currently emitted signal.

fn stop_signal_emission_by_name(&self, signal_name: &str)

Stop emission of the currently emitted signal by the (possibly detailed) signal name.

fn connect<F>(
    &self,
    signal_name: &str,
    after: bool,
    callback: F
) -> SignalHandlerIdwhere
    F: Fn(&[Value]) -> Option<Value> + Send + Sync + 'static,

Connect to the signal signal_name on this object. Read more

fn connect_id<F>(
    &self,
    signal_id: SignalId,
    details: Option<Quark>,
    after: bool,
    callback: F
) -> SignalHandlerIdwhere
    F: Fn(&[Value]) -> Option<Value> + Send + Sync + 'static,

Connect to the signal signal_id on this object. Read more

fn connect_local<F>(
    &self,
    signal_name: &str,
    after: bool,
    callback: F
) -> SignalHandlerIdwhere
    F: Fn(&[Value]) -> Option<Value> + 'static,

Connect to the signal signal_name on this object. Read more

fn connect_local_id<F>(
    &self,
    signal_id: SignalId,
    details: Option<Quark>,
    after: bool,
    callback: F
) -> SignalHandlerIdwhere
    F: Fn(&[Value]) -> Option<Value> + 'static,

Connect to the signal signal_id on this object. Read more

unsafe fn connect_unsafe<F>(
    &self,
    signal_name: &str,
    after: bool,
    callback: F
) -> SignalHandlerIdwhere
    F: Fn(&[Value]) -> Option<Value>,

Connect to the signal signal_name on this object. Read more

unsafe fn connect_unsafe_id<F>(
    &self,
    signal_id: SignalId,
    details: Option<Quark>,
    after: bool,
    callback: F
) -> SignalHandlerIdwhere
    F: Fn(&[Value]) -> Option<Value>,

Connect to the signal signal_id on this object. Read more

fn connect_closure(
    &self,
    signal_name: &str,
    after: bool,
    closure: RustClosure
) -> SignalHandlerId

Connect a closure to the signal signal_name on this object. Read more

fn connect_closure_id(
    &self,
    signal_id: SignalId,
    details: Option<Quark>,
    after: bool,
    closure: RustClosure
) -> SignalHandlerId

Connect a closure to the signal signal_id on this object. Read more

fn watch_closure(&self, closure: &impl AsRef<Closure>)

Limits the lifetime of closure to the lifetime of the object. When the object’s reference count drops to zero, the closure will be invalidated. An invalidated closure will ignore any calls to invoke_with_values, or invoke when using Rust closures.

fn emit<R>(&self, signal_id: SignalId, args: &[&dyn ToValue]) -> Rwhere
R: TryFromClosureReturnValue,

Emit signal by signal id. Read more

fn emit_with_values(&self, signal_id: SignalId, args: &[Value]) -> Option<Value>

Same as Self::emit but takes Value for the arguments.

fn emit_by_name<R>(&self, signal_name: &str, args: &[&dyn ToValue]) -> Rwhere
R: TryFromClosureReturnValue,

Emit signal by its name. Read more

fn emit_by_name_with_values(
    &self,
    signal_name: &str,
    args: &[Value]
) -> Option<Value>

Emit signal by its name. Read more

fn emit_by_name_with_details<R>(
    &self,
    signal_name: &str,
    details: Quark,
    args: &[&dyn ToValue]
) -> Rwhere
    R: TryFromClosureReturnValue,

Emit signal by its name with details. Read more

fn emit_by_name_with_details_and_values(
    &self,
    signal_name: &str,
    details: Quark,
    args: &[Value]
) -> Option<Value>

Emit signal by its name with details. Read more

fn emit_with_details<R>(
    &self,
    signal_id: SignalId,
    details: Quark,
    args: &[&dyn ToValue]
) -> Rwhere
    R: TryFromClosureReturnValue,

Emit signal by signal id with details. Read more

fn emit_with_details_and_values(
    &self,
    signal_id: SignalId,
    details: Quark,
    args: &[Value]
) -> Option<Value>

Emit signal by signal id with details. Read more

fn disconnect(&self, handler_id: SignalHandlerId)

Disconnect a previously connected signal handler.

fn connect_notify<F>(&self, name: Option<&str>, f: F) -> SignalHandlerIdwhere
F: Fn(&T, &ParamSpec) + Send + Sync + 'static,

Connect to the notify signal of the object. Read more

fn connect_notify_local<F>(&self, name: Option<&str>, f: F) -> SignalHandlerIdwhere
F: Fn(&T, &ParamSpec) + 'static,

Connect to the notify signal of the object. Read more

unsafe fn connect_notify_unsafe<F>(
    &self,
    name: Option<&str>,
    f: F
) -> SignalHandlerIdwhere
    F: Fn(&T, &ParamSpec),

Connect to the notify signal of the object. Read more

fn notify(&self, property_name: &str)

Notify that the given property has changed its value. Read more

fn notify_by_pspec(&self, pspec: &ParamSpec)

Notify that the given property has changed its value. Read more

fn downgrade(&self) -> WeakRef<T>

Downgrade this object to a weak reference.

fn add_weak_ref_notify<F>(&self, f: F) -> WeakRefNotify<T>where
F: FnOnce() + Send + 'static,

Add a callback to be notified when the Object is disposed.

fn add_weak_ref_notify_local<F>(&self, f: F) -> WeakRefNotify<T>where
F: FnOnce() + 'static,

Add a callback to be notified when the Object is disposed. Read more

fn bind_property<'f, 't, O, 'a>(
    &'a self,
    source_property: &'a str,
    target: &'a O,
    target_property: &'a str
) -> BindingBuilder<'a, 'f, 't>where
    O: ObjectType,

Bind property source_property on this object to the target_property on the target object. Read more

fn ref_count(&self) -> u32

Returns the strong reference count of this object.

unsafe fn run_dispose(&self)

Runs the dispose mechanism of the object. Read more

impl<T> Property for Twhere
T: HasParamSpec,

type Value = T

impl<T> PropertyGet for Twhere
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type Value = T

fn get<R, F>(&self, f: F) -> Rwhere
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Ensures that the type has been registered with the type system.

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T: Clone,

type Owned = T

The resulting type after obtaining ownership.

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type GlibType = <T as GlibPtrDefault>::GlibType

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Performs the conversion.

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