Implement headless rendering

src/osx/mod.rs

@@ -1,4 +1,10 @@
-use {Event, WindowBuilder};
+use Event;
+
+#[cfg(feature = "window")]
+use WindowBuilder;
+
+#[cfg(feature = "headless")]
+use HeadlessRendererBuilder;
 
 use cocoa::base::{id, NSUInteger, nil};
 use cocoa::appkit::*;
@@ -11,6 +17,14 @@ pub struct Window {
     context: id,
 }
 
+pub struct HeadlessContext(Window);
+
+impl Deref<Window> for HeadlessContext {
+    fn deref(&self) -> &Window {
+        &self.0
+    }
+}
+
 pub struct MonitorID;
 
 pub fn get_available_monitors() -> Vec<MonitorID> {
@@ -31,14 +45,28 @@ impl MonitorID {
     }
 }
 
+#[cfg(feature = "window")]
 impl Window {
-    pub fn new(_builder: WindowBuilder) -> Result<Window, String> {
+    pub fn new(builder: WindowBuilder) -> Result<Window, String> {
+        Window::new_impl(builder.dimensions, builder.title.as_slice(), true)
+    }
+}
 
+#[cfg(feature = "headless")]
+impl HeadlessContext {
+    pub fn new(builder: HeadlessRendererBuilder) -> Result<HeadlessContext, String> {
+        Window::new_impl(Some(builder.dimensions), "", false)
+            .map(|w| HeadlessContext(w))
+    }
+}
+
+impl Window {
+    fn new_impl(dimensions: Option<(uint, uint)>, title: &str, visible: bool) -> Result<Window, String> {
         let app = match Window::create_app() {
             Some(app) => app,
             None      => { return Err(format!("Couldn't create NSApplication")); },
         };
-        let window = match Window::create_window(_builder.dimensions.unwrap_or((800, 600)), _builder.title.as_slice()) {
+        let window = match Window::create_window(dimensions.unwrap_or((800, 600)), title) {
             Some(window) => window,
             None         => { return Err(format!("Couldn't create NSWindow")); },
         };