Add window cursor control

- added new `cursor` attribute, which defaults to `false` if a window is 
full-screen
- added documentation of this
- also added in missing documentation of `fullscreen` and `screen` 
window attributes

docs/windows.md

@@ -119,6 +119,28 @@ window rendering tree. If not specified, it defaults to `16` bits. The color
 depth of the actual `!window` on-screen frame-buffer cannot be controlled and
 is OS-defined.
 
+The `!window` node also supports the following specific attributes:
+
+`screen=` `0`...
+: Specifies which screen to open the window on. This is OS and configuration
+dependent, but generally screen `0` is the "main" screen and additional screens
+are numbered upwards from that. Default is `0` unless the `--screen`
+[command-line option](install.md#running-flitter) has been provided.
+
+`fullscreen=` [`true` | `false`]
+: Specifies whether to show the window in full-screen mode. If set to `true`,
+the window will be expanded to fill the entire screen. If the window `size`
+does not match the aspect ratio of the screen then black borders will be shown
+at the top/bottom or left/right sides as necessary. This attribute may be
+changed programmatically to switch the window in and out of full-screen mode.
+Default is `false` unless the `--fullscreen` [command-line
+option](install.md#running-flitter) has been provided.
+
+`cursor=` [`true` | `false`]
+: Whether the pointer cursor should be shown within the window. This attribute
+may be changed programmatically to show and hide the cursor. Default is
+`true` unless the window is in full-screen mode.
+
 The default shader program used for `!window` and `!offscreen` nodes is a
 single-pass shader that composites together the output textures of all child
 nodes. It can be controlled with the following additional attributes:

src/flitter/render/window/__init__.py

@@ -445,6 +445,7 @@ def __init__(self, screen=0, fullscreen=False, vsync=False, offscreen=False, **k
         self._visible = not offscreen
         self._screen = None
         self._fullscreen = None
+        self._cursor = None
         self._resizable = None
         self._title = None
         self._beat = None
@@ -476,6 +477,7 @@ def create(self, engine, node, resized, *, opengl_es=False, **kwargs):
         screen = node.get('screen', 1, int, self.default_screen)
         fullscreen = node.get('fullscreen', 1, bool, self.default_fullscreen) if self._visible else False
         resizable = node.get('resizable', 1, bool, True) if self._visible else False
+        cursor = node.get('cursor', 1, bool, not fullscreen)
         title = node.get('title', 1, str, "Flitter")
         if self.window is None:
             self.engine = engine
@@ -519,6 +521,9 @@ def create(self, engine, node, resized, *, opengl_es=False, **kwargs):
         if self._visible and resizable != self._resizable:
             glfw.set_window_attrib(self.window, glfw.RESIZABLE, glfw.TRUE if resizable else glfw.FALSE)
             self._resizable = resizable
+        if cursor != self._cursor:
+            glfw.set_input_mode(self.window, glfw.CURSOR, glfw.CURSOR_NORMAL if cursor else glfw.CURSOR_HIDDEN)
+            self._cursor = cursor
         if self._visible and (resized or screen != self._screen or fullscreen != self._fullscreen):
             monitors = glfw.get_monitors()
             monitor = monitors[screen] if screen < len(monitors) else monitors[0]