sizing: Create a standalone UI shape manager

The manager is used for sizing the layer surface. It promises never to exceed half the output height.

The selection of the current layout is not being done here, leading to worse behaviour in 1:1 scaling.

In the future, it could be used for sizing the keyboard itself and the suggestion box, as well as decide which layout to use, because layouts should have some sizing hints.

src/outputs.rs

@@ -17,7 +17,7 @@ pub mod c {
     // Defined in C
 
     #[repr(transparent)]
-    #[derive(Clone, PartialEq)]
+    #[derive(Clone, PartialEq, Copy)]
     pub struct WlOutput(*const c_void);
 
     #[repr(C)]
@@ -105,6 +105,24 @@ pub mod c {
 
     type COutputs = ::util::c::Wrapped<Outputs>;
 
+    /// A stable reference to an output.
+    #[derive(Clone)]
+    #[repr(C)]
+    pub struct OutputHandle {
+        wl_output: WlOutput,
+        outputs: COutputs,
+    }
+
+    impl OutputHandle {
+        // Cannot return an Output reference
+        // because COutputs is too deeply wrapped
+        pub fn get_state(&self) -> Option<OutputState> {
+            let outputs = self.outputs.clone_ref();
+            let outputs = outputs.borrow();
+            find_output(&outputs, self.wl_output.clone()).map(|o| o.current.clone())
+        }
+    }
+
     // Defined in Rust
 
     extern fn outputs_handle_geometry(
@@ -240,46 +258,15 @@ pub mod c {
     
     #[no_mangle]
     pub extern "C"
-    fn squeek_outputs_get_current(raw_collection: COutputs) -> WlOutput {
+    fn squeek_outputs_get_current(raw_collection: COutputs) -> OutputHandle {
         let collection = raw_collection.clone_ref();
         let collection = collection.borrow();
-        collection.outputs[0].output.clone()
-    }
-
-    #[no_mangle]
-    pub extern "C"
-    fn squeek_outputs_get_perceptual_width(
-        raw_collection: COutputs,
-        wl_output: WlOutput,
-    ) -> i32 {
-        let collection = raw_collection.clone_ref();
-        let collection = collection.borrow();
-
-        let output_state = find_output(&collection, wl_output)
-            .map(|o| &o.current);
-        match output_state {
-            Some(OutputState {
-                current_mode: Some(super::Mode { width, height } ),
-                transform: Some(transform),
-                scale,
-            }) => {
-                match transform {
-                    Transform::Normal
-                    | Transform::Rotated180
-                    | Transform::Flipped
-                    | Transform::FlippedRotated180 => width / scale,
-                    _ => height / scale,
-                }
-            },
-            _ => {
-                log_print!(
-                    logging::Level::Surprise,
-                    "Not enough info received on output",
-                );
-                0
-            },
+        OutputHandle {
+            wl_output: collection.outputs[0].output.clone(),
+            outputs: raw_collection.clone(),
         }
     }
+
     // TODO: handle unregistration
     
     fn find_output(
@@ -305,6 +292,14 @@ pub mod c {
     }
 }
 
+/// Generic size
+#[derive(Clone)]
+pub struct Size {
+    pub width: u32,
+    pub height: u32,
+}
+
+/// wl_output mode
 #[derive(Clone)]
 struct Mode {
     width: i32,
@@ -315,10 +310,16 @@ struct Mode {
 pub struct OutputState {
     current_mode: Option<Mode>,
     transform: Option<c::Transform>,
-    scale: i32,
+    pub scale: i32,
 }
 
 impl OutputState {
+    // More properly, this would have been a builder kind of struct,
+    // with wl_output gradually adding properties to it
+    // before it reached a fully initialized state,
+    // when it would transform into a struct without all (some?) of the Options.
+    // However, it's not clear which state is fully initialized,
+    // and whether it would make things easier at all anyway.
     fn uninitialized() -> OutputState {
         OutputState {
             current_mode: None,
@@ -326,6 +327,32 @@ impl OutputState {
             scale: 1,
         }
     }
+
+    pub fn get_pixel_size(&self) -> Option<Size> {
+        use self::c::Transform;
+        match self {
+            OutputState {
+                current_mode: Some(Mode { width, height } ),
+                transform: Some(transform),
+                scale: _,
+            } => Some(
+                match transform {
+                    Transform::Normal
+                    | Transform::Rotated180
+                    | Transform::Flipped
+                    | Transform::FlippedRotated180 => Size {
+                        width: *width as u32,
+                        height: *height as u32,
+                    },
+                    _ => Size {
+                        width: *height as u32,
+                        height: *width as u32,
+                    },
+                }
+            ),
+            _ => None,
+        }
+    }
 }
 
 pub struct Output {