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examples: Implement gst::ChildProxy interface in cairo compositor example

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This commit is contained in:
Sebastian Dröge 2022-03-30 21:37:26 +03:00
parent 2c7c46e153
commit ae234bb01e
1 changed files with 45 additions and 1 deletions
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46
examples/src/bin/cairo_compositor.rs
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@ -52,6 +52,7 @@ mod cairo_compositor {
const NAME: &'static str = "CairoCompositor";
type Type = super::CairoCompositor;
type ParentType = gst_video::VideoAggregator;
type Interfaces = (gst::ChildProxy,);
}
// Implementation of glib::Object virtual methods.
@ -179,6 +180,24 @@ mod cairo_compositor {
PAD_TEMPLATES.as_ref()
}
// Notify via the child proxy interface whenever a new pad is added or removed.
fn request_new_pad(
&self,
element: &Self::Type,
templ: &gst::PadTemplate,
name: Option<String>,
caps: Option<&gst::Caps>,
) -> Option<gst::Pad> {
let pad = self.parent_request_new_pad(element, templ, name, caps)?;
element.child_added(&pad, &pad.name());
Some(pad)
}
fn release_pad(&self, element: &Self::Type, pad: &gst::Pad) {
element.child_removed(pad, &pad.name());
self.parent_release_pad(element, pad);
}
}
// Implementation of gst_base::Aggregator virtual methods.
@ -306,6 +325,31 @@ mod cairo_compositor {
Ok(gst::FlowSuccess::Ok)
}
}
// Implementation of gst::ChildProxy virtual methods.
//
// This allows accessing the pads and their properties from e.g. gst-launch.
impl ChildProxyImpl for CairoCompositor {
fn children_count(&self, object: &Self::Type) -> u32 {
object.num_pads() as u32
}
fn child_by_name(&self, object: &Self::Type, name: &str) -> Option<glib::Object> {
object
.pads()
.into_iter()
.find(|p| p.name() == name)
.map(|p| p.upcast())
}
fn child_by_index(&self, object: &Self::Type, index: u32) -> Option<glib::Object> {
object
.pads()
.into_iter()
.nth(index as usize)
.map(|p| p.upcast())
}
}
}
// Creates a cairo context around the given video frame and then calls the closure to operate
@ -376,7 +420,7 @@ mod cairo_compositor {
// This here defines the public interface of our element and implements
// the corresponding traits so that it behaves like any other gst::Element.
glib::wrapper! {
pub struct CairoCompositor(ObjectSubclass<imp::CairoCompositor>) @extends gst_video::VideoAggregator, gst_base::Aggregator, gst::Element, gst::Object;
pub struct CairoCompositor(ObjectSubclass<imp::CairoCompositor>) @extends gst_video::VideoAggregator, gst_base::Aggregator, gst::Element, gst::Object, @implements gst::ChildProxy;
}
impl CairoCompositor {