Add command line override for font system

src/font/mod.rs

@@ -86,19 +86,40 @@ impl FontSystemSelection {
             }
         }
     }
+    pub fn variants() -> Vec<&'static str> {
+        vec![
+            "FontConfigAndFreeType",
+            "FontLoaderAndFreeType",
+            "FontLoaderAndRustType",
+            "CoreText",
+        ]
+    }
 }
 
-fn new_font_system() -> Box<FontSystem> {
-    FontSystemSelection::default().new_font_system()
+impl std::str::FromStr for FontSystemSelection {
+    type Err = Error;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s.to_lowercase().as_ref() {
+            "fontconfigandfreetype" => Ok(FontSystemSelection::FontConfigAndFreeType),
+            "fontloadandfreetype" => Ok(FontSystemSelection::FontLoaderAndFreeType),
+            "fontloaderandrusttype" => Ok(FontSystemSelection::FontLoaderAndRustType),
+            "coretext" => Ok(FontSystemSelection::CoreText),
+            _ => Err(format_err!(
+                "{} is not a valid FontSystemSelection variant, possible values are {:?}",
+                s,
+                FontSystemSelection::variants()
+            )),
+        }
+    }
 }
 
 impl FontConfiguration {
     /// Create a new empty configuration
-    pub fn new(config: Rc<Config>) -> Self {
+    pub fn new(config: Rc<Config>, system: FontSystemSelection) -> Self {
         Self {
             config,
             fonts: RefCell::new(HashMap::new()),
-            system: new_font_system(),
+            system: system.new_font_system(),
         }
     }
 

src/main.rs

@@ -24,7 +24,7 @@ use crate::guiloop::GuiSelection;
 use crate::guiloop::GuiSystem;
 
 mod font;
-use crate::font::FontConfiguration;
+use crate::font::{FontConfiguration, FontSystemSelection};
 
 mod pty;
 pub use crate::pty::{openpty, Child, Command, ExitStatus, MasterPty, SlavePty};
@@ -82,6 +82,15 @@ struct Opt {
     )]
     gui_system: Option<GuiSelection>,
 
+    #[structopt(
+        long = "font-system",
+        raw(
+            possible_values = "&FontSystemSelection::variants()",
+            case_insensitive = "true"
+        )
+    )]
+    font_system: Option<FontSystemSelection>,
+
     /// Instead of executing your shell, run PROG.
     /// For example: `wezterm -- bash -l` will spawn bash
     /// as if it were a login shell.
@@ -96,9 +105,10 @@ fn main() -> Result<(), Error> {
     } else {
         config::Config::load()?
     });
-    println!("Using configuration: {:#?}", config);
+    println!("Using configuration: {:#?}\nopts: {:#?}", config, opts);
 
-    let fontconfig = Rc::new(FontConfiguration::new(Rc::clone(&config)));
+    let font_system = opts.font_system.unwrap_or(config.font_system);
+    let fontconfig = Rc::new(FontConfiguration::new(Rc::clone(&config), font_system));
 
     let cmd = if opts.prog.len() > 0 {
         Some(opts.prog.iter().map(|x| x.as_os_str()).collect())