Added only secondary screen option

src/lib.rs

@@ -309,6 +309,22 @@ impl MultiScreen {
         }
     }
 
+    /// Returns the arguments for enabling only the second screen.
+    pub fn only_secondary_args(&self) -> Option<Vec<String>> {
+        if let Some((ref main, ref second)) = self.main_screens() {
+            Some(vec![
+                "--output".to_owned(),
+                main.name.clone(),
+                "--off".to_owned(),
+                "--output".to_owned(),
+                second.name.clone(),
+                "--auto".to_owned(),
+            ])
+        } else {
+            None
+        }
+    }
+
     /// Calls the xrandr program to disable all screens except the primary.
     pub fn only_primary(&self) -> Result<(), Error> {
         self.run_command(self.only_primary_args())
@@ -332,9 +348,17 @@ impl MultiScreen {
         }
     }
 
+    /// Calls the xrandr program to enable only the second screen.
+    pub fn only_secondary(&self) -> Result<(), Error> {
+        if let Some(args) = self.only_secondary_args() {
+            self.run_command(args)
+        } else {
+            Err(Error::NoScreenDetected)
+        }
+    }
+
     /// Run an xrandr command with its args.
     pub fn run_command(&self, args: Vec<String>) -> Result<(), Error> {
-
         Command::new("xrandr")
             .args(args)
             .spawn()?

src/tv.rs

@@ -10,7 +10,7 @@ fn main() {
              .help("Action to do")
              .takes_value(true)
              .value_name("ACTION")
-             .possible_values(&["disable", "duplicate", "enable"])
+             .possible_values(&["disable", "duplicate", "enable","only-secondary"])
              .required(true))
         .arg(Arg::with_name("position")
              .help("Specify the position of the second screen")
@@ -35,6 +35,7 @@ fn main() {
             let side = matches.value_of("position").unwrap().parse().unwrap();
             screens.two_screens(side)
         },
+        Some("only-secondary") => screens.only_secondary(),
         // Can never happen, clap will crash before this
         _ => Ok(())
     };