Add mouse cursor support

Add a new api, window.set_cursor, for setting the cursor. The enum MouseCursor lists the possible cursors.

Only X11 is implemented. On OSX, Android, & Win32 the window.set_cursor function
either does nothing or calls the "unimplemented!" macro.

src/android/mod.rs

@@ -280,6 +280,9 @@ impl Window {
 
     pub fn set_window_resize_callback(&mut self, _: Option<fn(uint, uint)>) {
     }
+
+    pub fn set_cursor(&self, cursor: MouseCursor) {
+    }
 }
 
 unsafe impl Send for Window {}

src/lib.rs

@@ -90,6 +90,62 @@ pub enum Api {
     OpenGlEs,
 }
 
+#[derive(Show, Copy)]
+pub enum MouseCursor {
+    /// The platform-dependent default cursor.
+    Default,
+    /// A simple crosshair.
+    Crosshair,
+    /// A hand (often used to indicate links in web browsers).
+    Hand,
+    /// Self explanatory.
+    Arrow,
+    /// Indicates something is to be moved.
+    Move,
+    /// Indicates text that may be selected or edited.
+    Text,
+    /// Program busy indicator.
+    Wait,
+    /// Help indicator (often rendered as a "?")
+    Help,
+    /// Progress indicator. Shows that processing is being done. But in contrast
+    /// with "Wait" the user may still interact with the program. Often rendered
+    /// as a spinning beach ball, or an arrow with a watch or hourglass. 
+    Progress,
+
+    /// Cursor showing that something cannot be done.
+    NotAllowed,
+    ContextMenu,
+    NoneCursor,
+    Cell,
+    VerticalText,
+    Alias,
+    Copy,
+    NoDrop,
+    Grab,
+    Grabbing,
+    AllScroll,
+    ZoomIn,
+    ZoomOut,
+
+    /// Indicate that some edge is to be moved. For example, the 'SeResize' cursor
+    /// is used when the movement starts from the south-east corner of the box.
+    EResize,
+    NResize,
+    NeResize,
+    NwResize,
+    SResize,
+    SeResize,
+    SwResize,
+    WResize,
+    EwResize,
+    NsResize,
+    NeswResize,
+    NwseResize,
+    ColResize,
+    RowResize,
+}
+
 /// Object that allows you to build windows.
 #[cfg(feature = "window")]
 pub struct WindowBuilder<'a> {
@@ -559,6 +615,11 @@ impl Window {
     pub fn set_window_resize_callback(&mut self, callback: Option<fn(uint, uint)>) {
         self.window.set_window_resize_callback(callback);
     }
+
+    /// Modifies the mouse cursor of the window.
+    pub fn set_cursor(&mut self, cursor: MouseCursor) {
+        self.window.set_cursor(cursor);
+    }
 }
 
 #[cfg(feature = "window")]

src/osx/mod.rs

@@ -491,4 +491,8 @@ impl Window {
     pub fn set_window_resize_callback(&mut self, callback: Option<fn(uint, uint)>) {
         self.resize = callback;
     }
+
+    pub fn set_cursor(&self, cursor: MouseCursor) {
+        unimplemented!()
+    }
 }

src/win32/mod.rs

@@ -285,6 +285,10 @@ impl Window {
 
     pub fn set_window_resize_callback(&mut self, _: Option<fn(uint, uint)>) {
     }
+
+    pub fn set_cursor(&self, cursor: MouseCursor) {
+        unimplemented!()
+    }
 }
 
 #[unsafe_destructor]

src/x11/ffi.rs

@@ -1384,6 +1384,7 @@ extern "C" {
 #[link(name = "GL")]
 #[link(name = "X11")]
 #[link(name = "Xxf86vm")]
+#[link(name = "Xcursor")]
 extern "C" {
     pub fn XCloseDisplay(display: *mut Display);
     pub fn XCheckMaskEvent(display: *mut Display, event_mask: libc::c_long,
@@ -1454,6 +1455,9 @@ extern "C" {
         x: libc::c_int, y: libc::c_int) -> Bool;
     pub fn XF86VidModeGetAllModeLines(dpy: *mut Display, screen: libc::c_int,
         modecount_return: *mut libc::c_int, modesinfo: *mut *mut *mut XF86VidModeModeInfo) -> Bool;
+
+    pub fn XcursorLibraryLoadCursor(dpy: *mut Display, name: *const libc::c_char) -> Cursor;
+    pub fn XDefineCursor(dby: *mut Display, w: Window, cursor: Cursor);
 }
 
 /*

src/x11/window/mod.rs

@@ -1,4 +1,4 @@
-use {Event, BuilderAttribs};
+use {Event, BuilderAttribs, MouseCursor};
 use CreationError;
 use CreationError::OsError;
 use libc;
@@ -611,4 +611,48 @@ impl Window {
 
     pub fn set_window_resize_callback(&mut self, _: Option<fn(uint, uint)>) {
     }
+
+    pub fn set_cursor(&self, cursor: MouseCursor) {
+        unsafe {
+            use std::ffi::CString;
+            let cursor_name = match cursor {
+                MouseCursor::Default => "left_ptr",
+                MouseCursor::Crosshair => "crosshair",
+                MouseCursor::Hand => "hand",
+                MouseCursor::Arrow => "arrow",
+                MouseCursor::Move => "fleur",
+                MouseCursor::Text => "xterm",
+                MouseCursor::Wait => "watch",
+                MouseCursor::Help => "question_arrow",
+                MouseCursor::Progress => "watch", // TODO: Find better matching X11 cursor
+                MouseCursor::EResize => "right_side",
+                MouseCursor::NResize => "top_side",
+                MouseCursor::NeResize => "top_right_corner",
+                MouseCursor::NwResize => "top_left_corner",
+                MouseCursor::SResize => "bottom_side",
+                MouseCursor::SeResize => "bottom_right_corner",
+                MouseCursor::SwResize => "bottom_left_corner",
+                MouseCursor::WResize => "left_side",
+                MouseCursor::EwResize => "h_double_arrow",
+                MouseCursor::NsResize => "v_double_arrow",
+
+                
+                MouseCursor::NeswResize | MouseCursor::NwseResize => "sizing", // TODO: Better matching X11 cursor
+                
+                MouseCursor::ColResize | MouseCursor::RowResize => "double_arrow", // TODO: Better matching X11 cursor
+
+                /// TODO: Find matching X11 cursors
+                MouseCursor::NotAllowed | MouseCursor::ContextMenu |
+                MouseCursor::NoneCursor | MouseCursor::Cell |
+                MouseCursor::VerticalText | MouseCursor::Alias |
+                MouseCursor::Copy | MouseCursor::NoDrop | MouseCursor::Grab |
+                MouseCursor::Grabbing | MouseCursor::AllScroll |
+                MouseCursor::ZoomIn | MouseCursor::ZoomOut => "left_ptr",
+            };
+            let c_string = CString::from_slice(cursor_name.as_bytes());
+            let xcursor = ffi::XcursorLibraryLoadCursor(self.x.display, c_string.as_ptr());
+            ffi::XDefineCursor (self.x.display, self.x.window, xcursor);
+            ffi::XFlush(self.x.display);
+        }
+    }
 }