Move set_cursor_position to the graphics backend

src/backend/glutin.rs

@@ -2,6 +2,7 @@
 
 
 use backend::{SeatInternal, TouchSlotInternal};
+use backend::graphics::GraphicsBackend;
 use backend::graphics::opengl::{Api, OpenglGraphicsBackend, PixelFormat, SwapBuffersError};
 use backend::input::{Axis, AxisSource, InputBackend, InputHandler, KeyState, MouseButton, MouseButtonState,
                      Seat, SeatCapabilities, TouchEvent, TouchSlot};
@@ -79,6 +80,13 @@ impl GlutinHeadlessRenderer {
     }
 }
 
+impl GraphicsBackend for GlutinHeadlessRenderer {
+    fn set_cursor_position(&mut self, _x: u32, _y: u32) -> Result<(), ()> {
+        //FIXME: Maybe save position? Is it of any use?
+        Ok(())
+    }
+}
+
 impl OpenglGraphicsBackend for GlutinHeadlessRenderer {
     #[inline]
     fn swap_buffers(&self) -> Result<(), SwapBuffersError> {
@@ -130,6 +138,17 @@ impl GlutinWindowedRenderer {
     }
 }
 
+impl GraphicsBackend for GlutinWindowedRenderer {
+    fn set_cursor_position(&mut self, x: u32, y: u32) -> Result<(), ()> {
+        if let Some((win_x, win_y)) = self.window.get_position() {
+            self.window
+                .set_cursor_position(win_x + x as i32, win_y + y as i32)
+        } else {
+            Err(())
+        }
+    }
+}
+
 impl OpenglGraphicsBackend for GlutinWindowedRenderer {
     #[inline]
     fn swap_buffers(&self) -> Result<(), SwapBuffersError> {
@@ -233,15 +252,6 @@ impl InputBackend for GlutinInputBackend {
         &mut self.input_config
     }
 
-    fn set_cursor_position(&mut self, x: u32, y: u32) -> Result<(), ()> {
-        if let Some((win_x, win_y)) = self.window.get_position() {
-            self.window
-                .set_cursor_position(win_x + x as i32, win_y + y as i32)
-        } else {
-            Err(())
-        }
-    }
-
     /// Processes new events of the underlying event loop to drive the set `InputHandler`.
     ///
     /// You need to periodically call this function to keep the underlying event loop and

src/backend/graphics/mod.rs

@@ -2,5 +2,22 @@
 //!
 //! Note: Not every api may be supported by every backend
 
+/// General functions any graphics backend should support independently from it's rendering
+/// techique.
+pub trait GraphicsBackend {
+    /// Sets the cursor position and therefor updates the drawn cursors position.
+    /// Useful as well for e.g. pointer wrapping.
+    ///
+    /// Not guaranteed to be supported on every backend. The result usually
+    /// depends on the backend, the cursor might be "owned" by another more priviledged
+    /// compositor (running nested).
+    ///
+    /// In these cases setting the position is actually not required, as movement is done
+    /// by the higher compositor and not by the backend. It is still good practice to update
+    /// the position after every recieved event, but don't rely on pointer wrapping working.
+    ///
+    fn set_cursor_position(&mut self, x: u32, y: u32) -> Result<(), ()>;
+}
+
 pub mod software;
 pub mod opengl;

src/backend/graphics/opengl.rs

@@ -2,6 +2,8 @@
 
 use nix::c_void;
 
+use super::GraphicsBackend;
+
 /// Error that can happen when swapping buffers.
 #[derive(Debug, Clone)]
 pub enum SwapBuffersError {
@@ -61,7 +63,7 @@ pub struct PixelFormat {
 
 /// Trait that describes objects that have an OpenGl context
 /// and can be used to render upon
-pub trait OpenglGraphicsBackend {
+pub trait OpenglGraphicsBackend: GraphicsBackend {
     /// Swaps buffers at the end of a frame.
     fn swap_buffers(&self) -> Result<(), SwapBuffersError>;
 

src/backend/graphics/software.rs

@@ -3,8 +3,10 @@
 use std::error::Error;
 use wayland_server::protocol::wl_shm::Format;
 
+use super::GraphicsBackend;
+
 /// Trait that describes objects providing a software rendering implementation
-pub trait CpuGraphicsBackend<E: Error> {
+pub trait CpuGraphicsBackend<E: Error>: GraphicsBackend {
     /// Render a given buffer of a given format at a specified place in the framebuffer
     ///
     /// # Error

src/backend/input.rs

@@ -218,13 +218,6 @@ pub trait InputBackend: Sized {
 
     /// Processes new events of the underlying backend and drives the `InputHandler`.
     fn dispatch_new_events(&mut self) -> Result<(), Self::EventError>;
-
-    /// Sets the cursor position, useful for e.g. pointer wrapping.
-    ///
-    /// Not guaranteed to be supported on every backend. The result usually
-    /// depends on the capability of the backend, but may also fail for certain
-    /// specific actions. See the backends documentation.
-    fn set_cursor_position(&mut self, x: u32, y: u32) -> Result<(), ()>;
 }
 
 /// Implement to receive input events from any `InputBackend`.

src/backend/libinput.rs

@@ -80,13 +80,6 @@ impl InputBackend for LibinputInputBackend {
         &mut self.devices
     }
 
-    fn set_cursor_position(&mut self, _x: u32, _y: u32) -> Result<(), ()> {
-        // FIXME later.
-        // This will be doable with the hardware cursor api and probably some more cases
-        warn!(self.logger, "Setting the cursor position is currently unsupported by the libinput backend");
-        Err(())
-    }
-
     fn dispatch_new_events(&mut self) -> Result<(), IoError> {
         self.context.dispatch()?;
         for event in &mut self.context {