examples: Add screen cast with pipewire (#247)

Fixes #155

.typos.toml

@@ -1,3 +1,4 @@
 [default.extend-words]
 # Ignore false-positives
 eis = "eis"
+datas = "datas"

Cargo.toml

@@ -64,6 +64,8 @@ zbus = { version = "5.0", default-features = false, features = ["url"] }
 [dev-dependencies]
 serde_json = "1.0"
 reis = { version = "0.4", features = ["tokio"] }
+pipewire = "0.8.0"
+tokio = { version = "1.41", features = [ "rt-multi-thread", "macros" ] }
 
 [package.metadata.docs.rs]
 features = ["backend", "gtk4", "raw_handle"]

examples/screen_cast_pw.rs

@@ -0,0 +1,224 @@
+use std::os::fd::{IntoRawFd, OwnedFd};
+
+use ashpd::desktop::{
+    screencast::{CursorMode, Screencast, SourceType, Stream as ScreencastStream},
+    PersistMode,
+};
+use pipewire as pw;
+use pw::{properties::properties, spa};
+
+struct UserData {
+    format: spa::param::video::VideoInfoRaw,
+}
+
+async fn open_portal() -> ashpd::Result<(ScreencastStream, OwnedFd)> {
+    let proxy = Screencast::new().await?;
+    let session = proxy.create_session().await?;
+    proxy
+        .select_sources(
+            &session,
+            CursorMode::Hidden,
+            SourceType::Monitor.into(),
+            false,
+            None,
+            PersistMode::DoNot,
+        )
+        .await?;
+
+    let response = proxy.start(&session, None).await?.response()?;
+    let stream = response
+        .streams()
+        .first()
+        .expect("no stream found / selected")
+        .to_owned();
+
+    let fd = proxy.open_pipe_wire_remote(&session).await?;
+
+    Ok((stream, fd))
+}
+
+async fn start_streaming(node_id: u32, fd: OwnedFd) -> Result<(), pw::Error> {
+    pw::init();
+
+    let mainloop = pw::main_loop::MainLoop::new(None)?;
+    let context = pw::context::Context::new(&mainloop)?;
+    let core = context.connect_fd(fd, None)?;
+
+    let data = UserData {
+        format: Default::default(),
+    };
+
+    let stream = pw::stream::Stream::new(
+        &core,
+        "video-test",
+        properties! {
+            *pw::keys::MEDIA_TYPE => "Video",
+            *pw::keys::MEDIA_CATEGORY => "Capture",
+            *pw::keys::MEDIA_ROLE => "Screen",
+        },
+    )?;
+
+    let _listener = stream
+        .add_local_listener_with_user_data(data)
+        .state_changed(|_, _, old, new| {
+            println!("State changed: {:?} -> {:?}", old, new);
+        })
+        .param_changed(|_, user_data, id, param| {
+            let Some(param) = param else {
+                return;
+            };
+            if id != pw::spa::param::ParamType::Format.as_raw() {
+                return;
+            }
+
+            let (media_type, media_subtype) =
+                match pw::spa::param::format_utils::parse_format(param) {
+                    Ok(v) => v,
+                    Err(_) => return,
+                };
+
+            if media_type != pw::spa::param::format::MediaType::Video
+                || media_subtype != pw::spa::param::format::MediaSubtype::Raw
+            {
+                return;
+            }
+
+            user_data
+                .format
+                .parse(param)
+                .expect("Failed to parse param changed to VideoInfoRaw");
+
+            println!("got video format:");
+            println!(
+                "\tformat: {} ({:?})",
+                user_data.format.format().as_raw(),
+                user_data.format.format()
+            );
+            println!(
+                "\tsize: {}x{}",
+                user_data.format.size().width,
+                user_data.format.size().height
+            );
+            println!(
+                "\tframerate: {}/{}",
+                user_data.format.framerate().num,
+                user_data.format.framerate().denom
+            );
+
+            // prepare to render video of this size
+        })
+        .process(|stream, _| {
+            match stream.dequeue_buffer() {
+                None => println!("out of buffers"),
+                Some(mut buffer) => {
+                    let datas = buffer.datas_mut();
+                    if datas.is_empty() {
+                        return;
+                    }
+
+                    // copy frame data to screen
+                    let data = &mut datas[0];
+                    println!("got a frame of size {}", data.chunk().size());
+                }
+            }
+        })
+        .register()?;
+
+    println!("Created stream {:#?}", stream);
+
+    let obj = pw::spa::pod::object!(
+        pw::spa::utils::SpaTypes::ObjectParamFormat,
+        pw::spa::param::ParamType::EnumFormat,
+        pw::spa::pod::property!(
+            pw::spa::param::format::FormatProperties::MediaType,
+            Id,
+            pw::spa::param::format::MediaType::Video
+        ),
+        pw::spa::pod::property!(
+            pw::spa::param::format::FormatProperties::MediaSubtype,
+            Id,
+            pw::spa::param::format::MediaSubtype::Raw
+        ),
+        pw::spa::pod::property!(
+            pw::spa::param::format::FormatProperties::VideoFormat,
+            Choice,
+            Enum,
+            Id,
+            pw::spa::param::video::VideoFormat::RGB,
+            pw::spa::param::video::VideoFormat::RGB,
+            pw::spa::param::video::VideoFormat::RGBA,
+            pw::spa::param::video::VideoFormat::RGBx,
+            pw::spa::param::video::VideoFormat::BGRx,
+            pw::spa::param::video::VideoFormat::YUY2,
+            pw::spa::param::video::VideoFormat::I420,
+        ),
+        pw::spa::pod::property!(
+            pw::spa::param::format::FormatProperties::VideoSize,
+            Choice,
+            Range,
+            Rectangle,
+            pw::spa::utils::Rectangle {
+                width: 320,
+                height: 240
+            },
+            pw::spa::utils::Rectangle {
+                width: 1,
+                height: 1
+            },
+            pw::spa::utils::Rectangle {
+                width: 4096,
+                height: 4096
+            }
+        ),
+        pw::spa::pod::property!(
+            pw::spa::param::format::FormatProperties::VideoFramerate,
+            Choice,
+            Range,
+            Fraction,
+            pw::spa::utils::Fraction { num: 25, denom: 1 },
+            pw::spa::utils::Fraction { num: 0, denom: 1 },
+            pw::spa::utils::Fraction {
+                num: 1000,
+                denom: 1
+            }
+        ),
+    );
+    let values: Vec<u8> = pw::spa::pod::serialize::PodSerializer::serialize(
+        std::io::Cursor::new(Vec::new()),
+        &pw::spa::pod::Value::Object(obj),
+    )
+    .unwrap()
+    .0
+    .into_inner();
+
+    let mut params = [spa::pod::Pod::from_bytes(&values).unwrap()];
+
+    stream.connect(
+        spa::utils::Direction::Input,
+        Some(node_id),
+        pw::stream::StreamFlags::AUTOCONNECT | pw::stream::StreamFlags::MAP_BUFFERS,
+        &mut params,
+    )?;
+
+    println!("Connected stream");
+
+    mainloop.run();
+
+    Ok(())
+}
+
+#[tokio::main]
+async fn main() {
+    let (stream, fd) = open_portal().await.expect("failed to open portal");
+    let pipewire_node_id = stream.pipe_wire_node_id();
+
+    println!(
+        "node id {}, fd {}",
+        pipewire_node_id,
+        &fd.try_clone().unwrap().into_raw_fd()
+    );
+
+    if let Err(e) = start_streaming(pipewire_node_id, fd).await {
+        eprintln!("Error: {}", e);
+    };
+}

src/desktop/camera.rs

@@ -16,6 +16,19 @@
 //!     Ok(())
 //! }
 //! ```
+//! An example on how to connect with Pipewire can be found [here](https://github.com/bilelmoussaoui/ashpd/blob/master/examples/screen_cast_pw.rs).
+//! Although the example's primary focus is screen casting, stream connection logic remains the same -- with one accessibility change:
+//! ```rust,ignore
+//! let stream = pw::stream::Stream::new(
+//!    &core,
+//!    "video-test",
+//!    properties! {
+//!        *pw::keys::MEDIA_TYPE => "Video",
+//!        *pw::keys::MEDIA_CATEGORY => "Capture",
+//!        *pw::keys::MEDIA_ROLE => "Screen", // <-- make this 'Camera'
+//!    },
+//! )?;
+//! ```
 
 use std::{collections::HashMap, os::fd::OwnedFd};
 

src/desktop/screencast.rs

@@ -34,6 +34,7 @@
 //!     Ok(())
 //! }
 //! ```
+//! An example on how to connect with Pipewire can be found [here](https://github.com/bilelmoussaoui/ashpd/blob/master/examples/screen_cast_pw.rs).
 
 use std::{collections::HashMap, fmt::Debug, os::fd::OwnedFd};