font fallback guifont extension

src/editor/mod.rs

@@ -33,8 +33,7 @@ pub struct Editor {
     pub grid: CharacterGrid,
     pub title: String,
     pub mouse_enabled: bool,
-    pub font_name: Option<String>,
-    pub font_size: Option<f32>,
+    pub guifont: Option<String>,
     pub cursor: Cursor,
     pub default_style: Arc<Style>,
     pub defined_styles: HashMap<u64, Arc<Style>>,
@@ -49,8 +48,7 @@ impl Editor {
             grid: CharacterGrid::new(window_geometry_or_default()),
             title: "Neovide".to_string(),
             mouse_enabled: true,
-            font_name: None,
-            font_size: None,
+            guifont: None,
             cursor: Cursor::new(),
             default_style: Arc::new(Style::new(Colors::new(
                 Some(colors::WHITE),
@@ -307,14 +305,8 @@ impl Editor {
     fn set_option(&mut self, gui_option: GuiOption) {
         trace!("Option set {:?}", &gui_option);
         match gui_option {
-            GuiOption::GuiFont(font_description) => {
-                let parts: Vec<&str> = font_description.split(':').collect();
-                self.font_name = Some(parts[0].to_string());
-                for part in parts.iter().skip(1) {
-                    if part.starts_with('h') && part.len() > 1 {
-                        self.font_size = part[1..].parse::<f32>().ok();
-                    }
-                }
+            GuiOption::GuiFont(guifont) => {
+                self.guifont = Some(guifont);
             }
             _ => {}
         }

src/renderer/caching_shaper.rs

@@ -10,7 +10,11 @@ use log::{trace, warn};
 use lru::LruCache;
 use skribo::{FontCollection, FontFamily, FontRef as SkriboFont, LayoutSession, TextStyle};
 use skulpin::skia_safe::{Data, Font as SkiaFont, TextBlob, TextBlobBuilder, Typeface};
+
 use std::collections::HashMap;
+use std::iter;
+
+use super::font_options::FontOptions;
 
 const STANDARD_CHARACTER_STRING: &str =
     "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
@@ -158,29 +162,27 @@ struct ShapeKey {
 
 pub fn build_collection_by_font_name(
     loader: &mut FontLoader,
-    font_name: Option<&str>,
+    fallback_list: &Vec<String>,
     bold: bool,
     italic: bool,
 ) -> FontCollection {
     let mut collection = FontCollection::new();
 
-    if let Some(font_name) = font_name {
-        let weight = if bold { Weight::BOLD } else { Weight::NORMAL };
-        let style = if italic { Style::Italic } else { Style::Normal };
-        let properties = Properties {
-            weight,
-            style,
-            stretch: Stretch::NORMAL,
-        };
-
-        let gui_fonts = &[font_name, SYSTEM_DEFAULT_FONT];
-
-        for font_name in gui_fonts {
-            if let Some(family) = loader.get_or_load(font_name, false) {
-                if let Some(font) = family.get(properties) {
-                    collection.add_family(FontFamily::new_from_font(font.clone()));
-                    break;
-                }
+    let weight = if bold { Weight::BOLD } else { Weight::NORMAL };
+    let style = if italic { Style::Italic } else { Style::Normal };
+    let properties = Properties {
+        weight,
+        style,
+        stretch: Stretch::NORMAL,
+    };
+
+    let gui_fonts = fallback_list.iter().map(|fallback_item| fallback_item.as_ref()).chain(iter::once(SYSTEM_DEFAULT_FONT));
+
+    for font_name in gui_fonts {
+        if let Some(family) = loader.get_or_load(font_name, false) {
+            if let Some(font) = family.get(properties) {
+                collection.add_family(FontFamily::new_from_font(font.clone()));
+                break;
             }
         }
     }
@@ -207,11 +209,11 @@ struct FontSet {
 }
 
 impl FontSet {
-    fn new(font_name: Option<&str>, mut loader: &mut FontLoader) -> FontSet {
+    fn new(fallback_list: &Vec<String>, mut loader: &mut FontLoader) -> FontSet {
         FontSet {
-            normal: build_collection_by_font_name(&mut loader, font_name, false, false),
-            bold: build_collection_by_font_name(&mut loader, font_name, true, false),
-            italic: build_collection_by_font_name(&mut loader, font_name, false, true),
+            normal: build_collection_by_font_name(&mut loader, fallback_list, false, false),
+            bold: build_collection_by_font_name(&mut loader, fallback_list, true, false),
+            italic: build_collection_by_font_name(&mut loader, fallback_list, false, true),
         }
     }
 
@@ -225,8 +227,7 @@ impl FontSet {
 }
 
 pub struct CachingShaper {
-    pub font_name: Option<String>,
-    pub base_size: f32,
+    pub options: FontOptions,
     font_set: FontSet,
     font_loader: FontLoader,
     font_cache: LruCache<String, SkiaFont>,
@@ -243,12 +244,14 @@ fn build_skia_font_from_skribo_font(skribo_font: &SkriboFont, base_size: f32) ->
 
 impl CachingShaper {
     pub fn new() -> CachingShaper {
+        let options = FontOptions::new(String::from(SYSTEM_DEFAULT_FONT), DEFAULT_FONT_SIZE);
         let mut loader = FontLoader::new();
+        let font_set = FontSet::new(&options.fallback_list, &mut loader);
+
 
         CachingShaper {
-            font_name: Some(String::from(SYSTEM_DEFAULT_FONT)),
-            base_size: DEFAULT_FONT_SIZE,
-            font_set: FontSet::new(Some(SYSTEM_DEFAULT_FONT), &mut loader),
+            options,
+            font_set,
             font_loader: loader,
             font_cache: LruCache::new(10),
             blob_cache: LruCache::new(10000),
@@ -259,7 +262,7 @@ impl CachingShaper {
         let font_name = skribo_font.font.postscript_name()?;
 
         if !self.font_cache.contains(&font_name) {
-            let font = build_skia_font_from_skribo_font(skribo_font, self.base_size)?;
+            let font = build_skia_font_from_skribo_font(skribo_font, self.options.size)?;
             self.font_cache.put(font_name.clone(), font);
         }
 
@@ -279,12 +282,12 @@ impl CachingShaper {
 
     pub fn shape(&mut self, text: &str, bold: bool, italic: bool) -> Vec<TextBlob> {
         let style = TextStyle {
-            size: self.base_size,
+            size: self.options.size,
         };
 
         let session = LayoutSession::create(text, &style, &self.font_set.get(bold, italic));
         let metrics = self.metrics();
-        let ascent = metrics.ascent * self.base_size / metrics.units_per_em as f32;
+        let ascent = metrics.ascent * self.options.size / metrics.units_per_em as f32;
         let mut blobs = Vec::new();
 
         for layout_run in session.iter_all() {
@@ -321,21 +324,23 @@ impl CachingShaper {
         self.blob_cache.get(&key).unwrap()
     }
 
-    pub fn change_font(&mut self, font_name: Option<&str>, base_size: Option<f32>) {
-        trace!("Font changed {:?} {:?}", &font_name, &base_size);
-        self.font_name = font_name.map(|name| name.to_string());
-        self.base_size = base_size.unwrap_or(DEFAULT_FONT_SIZE);
-        self.font_set = FontSet::new(font_name, &mut self.font_loader);
-        self.font_cache.clear();
-        self.blob_cache.clear();
+    pub fn update_font(&mut self, guifont_setting: &str) -> bool {
+        let updated = self.options.update(guifont_setting);
+        if updated {
+            trace!("Font changed: {:?}", self.options);
+            self.font_set = FontSet::new(&self.options.fallback_list, &mut self.font_loader);
+            self.font_cache.clear();
+            self.blob_cache.clear();
+        }
+        updated
     }
 
     pub fn font_base_dimensions(&mut self) -> (f32, f32) {
         let metrics = self.metrics();
         let font_height =
-            (metrics.ascent - metrics.descent) * self.base_size / metrics.units_per_em as f32;
+            (metrics.ascent - metrics.descent) * self.options.size / metrics.units_per_em as f32;
         let style = TextStyle {
-            size: self.base_size,
+            size: self.options.size,
         };
         let session =
             LayoutSession::create(STANDARD_CHARACTER_STRING, &style, &self.font_set.normal);
@@ -363,6 +368,6 @@ impl CachingShaper {
 
     pub fn underline_position(&mut self) -> f32 {
         let metrics = self.metrics();
-        -metrics.underline_position * self.base_size / metrics.units_per_em as f32
+        -metrics.underline_position * self.options.size / metrics.units_per_em as f32
     }
 }

src/renderer/font_options.rs

@@ -0,0 +1,55 @@
+#[derive(Clone, PartialEq, Debug)]
+pub struct FontOptions {
+    previous_guifont_setting: Option<String>,
+    pub fallback_list: Vec<String>,
+    pub size: f32
+}
+
+impl FontOptions {
+    pub fn new(name: String, size: f32) -> FontOptions {
+        FontOptions {
+            previous_guifont_setting: None,
+            fallback_list: vec!(name),
+            size
+        }
+    }
+
+    pub fn update(self: &mut FontOptions, guifont_setting: &str) -> bool {
+        if self.previous_guifont_setting.is_some() && 
+            guifont_setting == self.previous_guifont_setting.as_ref().unwrap() {
+            return false;
+        }
+        self.previous_guifont_setting = Some(guifont_setting.to_string());
+
+        let mut parts = guifont_setting
+            .split(':')
+            .filter(|part| !part.is_empty());
+        let mut updated = false;
+
+        if let Some(parts) = parts.next() {
+           let parsed_fallback_list: Vec<String> = parts
+                .split(',')
+                .filter(|fallback| !fallback.is_empty())
+                .map(|fallback| fallback.to_string())
+                .collect();
+
+           if parsed_fallback_list.len() > 0 && self.fallback_list != parsed_fallback_list {
+               self.fallback_list = parsed_fallback_list;
+               updated = true;
+           }
+        }
+
+        for part in parts {
+            if part.starts_with('h') && part.len() > 1 {
+                if let Some(size) = part[1..].parse::<f32>().ok() {
+                    if (self.size - size).abs() > std::f32::EPSILON {
+                        self.size = size;
+                        updated = true;
+                    }
+                }
+            }
+        }
+
+        updated
+    }
+}

src/renderer/mod.rs

@@ -6,8 +6,10 @@ use skulpin::skia_safe::{colors, dash_path_effect, Budgeted, Canvas, Paint, Rect
 use skulpin::CoordinateSystemHelper;
 
 mod caching_shaper;
-
+pub mod font_options;
 pub mod cursor_renderer;
+
+pub use font_options::*;
 pub use caching_shaper::CachingShaper;
 
 use crate::editor::{Style, EDITOR};
@@ -44,11 +46,14 @@ impl Renderer {
         }
     }
 
-    fn set_font(&mut self, name: Option<&str>, size: Option<f32>) {
-        self.shaper.change_font(name, size);
-        let (font_width, font_height) = self.shaper.font_base_dimensions();
-        self.font_width = font_width;
-        self.font_height = font_height;
+    fn update_font(&mut self, guifont_setting: &str) -> bool {
+        let updated = self.shaper.update_font(guifont_setting);
+        if updated {
+            let (font_width, font_height) = self.shaper.font_base_dimensions();
+            self.font_width = font_width;
+            self.font_height = font_height;
+        }
+        updated
     }
 
     fn compute_text_region(&self, grid_pos: (u64, u64), cell_width: u64) -> Rect {
@@ -100,7 +105,7 @@ impl Renderer {
 
         if style.underline || style.undercurl {
             let line_position = self.shaper.underline_position();
-            let stroke_width = self.shaper.base_size / 10.0;
+            let stroke_width = self.shaper.options.size / 10.0;
             self.paint
                 .set_color(style.special(&default_style.colors).to_color());
             self.paint.set_stroke_width(stroke_width);
@@ -152,32 +157,19 @@ impl Renderer {
     ) -> bool {
         trace!("Rendering");
 
-        let ((draw_commands, should_clear), default_style, cursor, font_name, font_size) = {
+        let ((draw_commands, should_clear), default_style, cursor, guifont_setting) = {
             let mut editor = EDITOR.lock();
             (
                 editor.build_draw_commands(),
                 editor.default_style.clone(),
                 editor.cursor.clone(),
-                editor.font_name.clone(),
-                editor.font_size,
+                editor.guifont.clone()
             )
         };
 
-        let current_font = Some(self.shaper.font_name.clone().unwrap_or(String::from("")));
-        let editor_font = if font_name.clone().unwrap_or_default().is_empty() {
-            &current_font
-        } else {
-            &font_name
-        };
-
-        let font_changed = current_font != *editor_font
-            || font_size
-                .map(|new_size| (new_size - self.shaper.base_size).abs() > std::f32::EPSILON)
-                .unwrap_or(false);
-
-        if font_changed {
-            self.set_font(font_name.as_deref(), font_size);
-        }
+        let font_changed = guifont_setting
+            .map(|guifont| self.update_font(&guifont))
+            .unwrap_or(false);
 
         if should_clear {
             self.surface = None;