Improved handling of screen removal

* now, redraws are triggered when necessary, as pointed out in #26

src/wm/client.rs

@@ -731,6 +731,7 @@ impl ScreenSet {
         }
     }
 
+    /// Get an immutable reference to the set of screens.
     pub fn screens(&self) -> &[(Crtc, Screen)] {
         &self.screens
     }
@@ -799,17 +800,21 @@ impl ScreenSet {
         }
     }
 
-    /// Remove a CRTC from our list of screens.
-    pub fn remove(&mut self, old_crtc: Crtc) {
-        if let Some(&(crtc, _)) = self.screens.get(self.current_screen) {
+    /// Remove a CRTC from our list of screens and return whether a redraw is necessary.
+    pub fn remove(&mut self, old_crtc: Crtc) -> bool {
+        let ret = if let Some(&(crtc, _)) = self.screens.get(self.current_screen) {
             if crtc == old_crtc {
                 self.current_screen = 0;
+                true
+            } else {
+                false
             }
         } else {
             panic!("logic error in ScreenSet :O");
-        }
+        };
 
         self.screens.retain(|&(crtc, _)| crtc != old_crtc);
+        ret
     }
 
     /// Apply a screen matching to all screens (that is, CRTCs) that we know of.

src/wm/window_system.rs

@@ -136,7 +136,6 @@ impl<'a> Wm<'a> {
                         root: root,
                         randr_base: 0,
                         border_width: config.border_width,
-                        // TODO: remove this ugly hack
                         safe_x: screen.width_in_pixels() as u32,
                         border_colors: colors,
                         screens: try!(Wm::setup_screens(con, root)),
@@ -503,8 +502,11 @@ impl<'a> Wm<'a> {
             let crtc_change: randr::CrtcChange = ev.u().cc();
 
             if crtc_change.mode() == 0 {
-                self.screens.remove(crtc_change.crtc());
                 info!("a crtc/screen removed from the screen set");
+                if self.screens.remove(crtc_change.crtc()) {
+                    self.arrange_windows();
+                    self.reset_focus();
+                }
             } else {
                 self.screens.update(&crtc_change);
                 info!("a crtc/screen from the screen set changed");