add ability to list available fonts

src/bridge/ui_commands.rs

@@ -4,7 +4,7 @@ use std::sync::Arc;
 use log::error;
 use log::trace;
 
-use nvim_rs::Neovim;
+use nvim_rs::{Neovim, call_args, rpc::model::IntoVal};
 use tokio::sync::mpsc::{unbounded_channel, UnboundedReceiver};
 
 use crate::bridge::TxWrapper;
@@ -15,7 +15,9 @@ use crate::windows_utils::{
 };
 
 // Serial commands are any commands which must complete before the next value is sent. This
-// includes keyboard and mouse input which would cuase problems if sent out of order.
+// includes keyboard and mouse input which would cause problems if sent out of order.
+//
+// When in doubt, use Parallel Commands.
 #[derive(Debug, Clone)]
 pub enum SerialCommand {
     Keyboard(String),
@@ -113,6 +115,7 @@ pub enum ParallelCommand {
     FileDrop(String),
     FocusLost,
     FocusGained,
+    DisplayAvailableFonts(Vec<String>),
     #[cfg(windows)]
     RegisterRightClick,
     #[cfg(windows)]
@@ -140,6 +143,44 @@ impl ParallelCommand {
             ParallelCommand::FileDrop(path) => {
                 nvim.command(format!("e {}", path).as_str()).await.ok();
             }
+            ParallelCommand::DisplayAvailableFonts(fonts) => {
+                let mut content: Vec<String> = vec![
+                    "What follows are the font names available for guifont. To use one of these, type:",
+                    "",
+                    "    :set guifont=<font name>:h<font size>",
+                    "",
+                    "where <font name> is one of the following with spaces escaped",
+                    "and <font size> is the desired font size. As an example:",
+                    "",
+                    "    :set guifont=Cascadia\\ Code\\ PL:h12",
+                    "",
+                    "You may specify multiple fonts separated by commas like so:",
+                    "",
+                    "    :set guifont=Cascadia\\ Code\\ PL,Delugia\\ Nerd\\ Font:h12",
+                    "",
+                    "------------------------------",
+                    "Available Fonts on this System",
+                    "------------------------------",
+                ].into_iter().map(|text| text.to_owned()).collect();
+                content.extend(fonts);
+
+                nvim.command("split").await.ok();
+                nvim.command("noswapfile hide enew").await.ok();
+                nvim.command("setlocal buftype=nofile").await.ok();
+                nvim.command("setlocal bufhidden=hide").await.ok();
+                nvim.command("\"setlocal nobuflisted").await.ok();
+                nvim.command("\"lcd ~").await.ok();
+                nvim.command("file scratch").await.ok();
+                nvim.call(
+                    "nvim_buf_set_lines", 
+                    call_args![
+                        0i64,
+                        0i64,
+                        -1i64,
+                        false,
+                        content
+                    ]).await.ok();
+            }
             #[cfg(windows)]
             ParallelCommand::RegisterRightClick => {
                 if unregister_rightclick() {

src/editor/mod.rs

@@ -63,6 +63,7 @@ pub enum DrawCommand {
 pub enum WindowCommand {
     TitleChanged(String),
     SetMouseEnabled(bool),
+    ListAvailableFonts,
 }
 
 pub struct Editor {
@@ -421,9 +422,16 @@ impl Editor {
     fn set_option(&mut self, gui_option: GuiOption) {
         trace!("Option set {:?}", &gui_option);
         if let GuiOption::GuiFont(guifont) = gui_option {
+            if guifont == "*".to_owned() {
+                self.window_command_sender
+                    .send(WindowCommand::ListAvailableFonts)
+                    .ok();
+            }
+
             self.draw_command_batcher
                 .queue(DrawCommand::FontChanged(guifont))
                 .ok();
+
             for window in self.windows.values() {
                 window.redraw();
             }

src/renderer/fonts/caching_shaper.rs

@@ -106,6 +106,10 @@ impl CachingShaper {
         self.blob_cache.clear();
     }
 
+    pub fn font_names(&self) -> Vec<String> {
+        self.font_loader.font_names()
+    }
+
     fn info(&mut self) -> (Metrics, f32) {
         let font_pair = self.current_font_pair();
         let size = self.current_size();

src/renderer/fonts/font_loader.rs

@@ -162,4 +162,8 @@ impl FontLoader {
 
         Some(font_arc)
     }
+
+    pub fn font_names(&self) -> Vec<String> {
+        self.font_mgr.family_names().collect()
+    }
 }

src/renderer/grid_renderer.rs

@@ -41,6 +41,10 @@ impl GridRenderer {
         }
     }
 
+    pub fn font_names(&self) -> Vec<String> {
+        self.shaper.font_names()
+    }
+
     /// Convert PhysicalSize to grid size
     pub fn convert_physical_to_grid(&self, physical: PhysicalSize<u32>) -> Dimensions {
         Dimensions::from(physical) / self.font_dimensions

src/renderer/mod.rs

@@ -75,6 +75,10 @@ impl Renderer {
         }
     }
 
+    pub fn font_names(&self) -> Vec<String> {
+        self.grid_renderer.font_names()
+    }
+
     /// Draws frame
     ///
     /// # Returns

src/window/mod.rs

@@ -88,7 +88,8 @@ impl GlutinWindowWrapper {
                 WindowCommand::TitleChanged(new_title) => self.handle_title_changed(new_title),
                 WindowCommand::SetMouseEnabled(mouse_enabled) => {
                     self.mouse_manager.enabled = mouse_enabled
-                }
+                },
+                WindowCommand::ListAvailableFonts => self.send_font_names(),
             }
         }
     }
@@ -98,6 +99,11 @@ impl GlutinWindowWrapper {
         self.windowed_context.window().set_title(&self.title);
     }
 
+    pub fn send_font_names(&self) {
+        let font_names = self.renderer.font_names();
+        self.ui_command_sender.send(UiCommand::Parallel(ParallelCommand::DisplayAvailableFonts(font_names))).unwrap();
+    }
+
     pub fn handle_quit(&mut self) {
         if SETTINGS.get::<CmdLineSettings>().remote_tcp.is_none() {
             self.ui_command_sender