feat: add properties to offset frame

src/pingxelflutsink/imp.rs

@@ -1,4 +1,4 @@
-use gstreamer::glib::{self, ParamSpec, ParamSpecBoolean, ParamSpecString, Value};
+use gstreamer::glib::{self, ParamSpec, ParamSpecBoolean, ParamSpecString, ParamSpecUInt, Value};
 use gstreamer::prelude::*;
 use gstreamer::subclass::prelude::*;
 use gstreamer::subclass::ElementMetadata;
@@ -35,6 +35,8 @@ struct Settings {
     bind_address: Option<SocketAddr>,
     diff_only: bool,
     prefix: Option<Ipv6Addr>,
+    x: u32,
+    y: u32,
 }
 
 #[derive(Default)]
@@ -79,6 +81,14 @@ impl ObjectImpl for PingxelflutSink {
                     .nick("Destination prefix")
                     .blurb("Prefix of pingxelflut server")
                     .build(),
+                ParamSpecUInt::builder("x")
+                    .nick("X offset")
+                    .blurb("Offset along X axis")
+                    .build(),
+                ParamSpecUInt::builder("y")
+                    .nick("Y offset")
+                    .blurb("Offset along Y axis")
+                    .build(),
             ]
         });
 
@@ -106,6 +116,12 @@ impl ObjectImpl for PingxelflutSink {
                     .map(|s| s.parse().ok())
                     .unwrap_or(None);
             }
+            "x" => {
+                settings.x = value.get::<u32>().unwrap();
+            }
+            "y" => {
+                settings.y = value.get::<u32>().unwrap();
+            }
             _ => unimplemented!(),
         }
     }
@@ -125,6 +141,8 @@ impl ObjectImpl for PingxelflutSink {
                 .as_ref()
                 .map(|addr| addr.to_string())
                 .to_value(),
+            "x" => settings.x.to_value(),
+            "y" => settings.y.to_value(),
             _ => unimplemented!(),
         }
     }
@@ -246,10 +264,11 @@ impl VideoSinkImpl for PingxelflutSink {
         let prefix = settings.prefix.as_ref().unwrap();
 
         if let State::Started { ref socket } = *self.state.lock().unwrap() {
-            for y in 0..cmp::min(frame.height(), HEIGHT) {
-                for x in 0..cmp::min(frame.width(), WIDTH) {
-                    let i =
-                        (y * frame.plane_stride()[0] as u32 + x * frame.n_components()) as usize;
+            for y in settings.y..cmp::min(settings.y + frame.height(), HEIGHT) {
+                for x in settings.x..cmp::min(settings.x + frame.width(), WIDTH) {
+                    let i = ((y - settings.y) * frame.plane_stride()[0] as u32
+                        + (x - settings.x) * frame.n_components())
+                        as usize;
                     let (r, g, b) = (data[i] as u16, data[i + 1] as u16, data[i + 2] as u16);
 
                     if settings.diff_only