Fix glyph cache crash

Author: InnocentusLime

src/text.rs

@@ -77,6 +77,13 @@ impl Font {
         self.atlas = atlas;
     }
 
+    pub(crate) fn set_characters(
+        &mut self,
+        characters: Arc<Mutex<HashMap<(char, u16), CharacterInfo>>>,
+    ) {
+        self.characters = characters;
+    }
+
     pub(crate) fn ascent(&self, font_size: f32) -> f32 {
         self.font.horizontal_line_metrics(font_size).unwrap().ascent
     }

src/ui/style.rs

@@ -10,7 +10,10 @@ use crate::{
     Error,
 };
 
-use std::sync::{Arc, Mutex};
+use std::{
+    collections::HashMap,
+    sync::{Arc, Mutex},
+};
 
 pub struct StyleBuilder {
     atlas: Arc<Mutex<Atlas>>,
@@ -60,6 +63,7 @@ impl StyleBuilder {
     pub fn with_font(self, font: &Font) -> Result<StyleBuilder, Error> {
         let mut font = font.clone();
         font.set_atlas(self.atlas.clone());
+        font.set_characters(Arc::new(Mutex::new(HashMap::new())));
         Ok(StyleBuilder {
             font: Arc::new(Mutex::new(font)),
             ..self