screencast: implement format negotation

src/portal/ptl_render_ctx.rs

@@ -1,6 +1,17 @@
-use {crate::gfx_api::GfxContext, std::rc::Rc, uapi::c};
+use {
+    crate::gfx_api::{GfxContext, GfxFormat},
+    ahash::AHashMap,
+    std::rc::Rc,
+    uapi::c,
+};
 
 pub struct PortalRenderCtx {
     pub _dev_id: c::dev_t,
     pub ctx: Rc<dyn GfxContext>,
 }
+
+pub struct PortalServerRenderCtx {
+    pub ctx: Rc<PortalRenderCtx>,
+    pub usable_formats: Rc<AHashMap<u32, GfxFormat>>,
+    pub server_formats: Option<AHashMap<u32, GfxFormat>>,
+}