opt: fetch rgba positively for sessions on flutter

src/flutter_ffi.rs

@@ -20,6 +20,7 @@ use std::{
     os::raw::c_char,
     str::FromStr,
 };
+use crate::ui_session_interface::InvokeUiSession;
 
 // use crate::hbbs_http::account::AuthResult;
 
@@ -47,7 +48,7 @@ fn initialize(app_dir: &str) {
 
 pub enum EventToUI {
     Event(String),
-    Rgba(ZeroCopyBuffer<Vec<u8>>),
+    Rgba,
 }
 
 pub fn start_global_event_stream(s: StreamSink<String>, app_type: String) -> ResultType<()> {
@@ -103,6 +104,16 @@ pub fn session_get_remember(id: String) -> Option<bool> {
     }
 }
 
+pub fn session_get_rgba(id: String) -> Option<ZeroCopyBuffer<Vec<u8>>> {
+    if let Some(session) = SESSIONS.read().unwrap().get(&id) {
+        return match session.get_rgba() {
+            Some(buf) => Some(ZeroCopyBuffer(buf)),
+            _ => None
+        };
+    }
+    None
+}
+
 pub fn session_get_toggle_option(id: String, arg: String) -> Option<bool> {
     if let Some(session) = SESSIONS.read().unwrap().get(&id) {
         Some(session.get_toggle_option(arg))