WIP - tweak get_glyph

core/embed/rust/librust_fonts.h

@@ -1,7 +1 @@
-typedef struct {
-  const uint8_t* ptr;
-  uint32_t len;
-} PointerData;
-
-// TODO: Theoretically, the `len` is not used by the client and does not have to be sent
-PointerData get_utf8_glyph(uint16_t char_code, int font);
+const uint8_t *get_utf8_glyph(uint16_t char_code, int font);

core/embed/rust/src/trezorhal/display.rs

@@ -72,7 +72,7 @@ pub fn char_width(ch: char, font: i32) -> i16 {
     text_width(encoding, font)
 }
 
-pub fn get_char_glyph(ch: u8, font: i32) -> *const u8 {
+pub fn get_char_glyph(ch: u16, font: i32) -> *const u8 {
     unsafe { ffi::font_get_glyph(font, ch) }
 }
 

core/embed/rust/src/ui/display/font.rs

@@ -144,22 +144,10 @@ impl Font {
         display::text_width(text, self.into())
     }
 
-    /// Supports UTF8 characters
-    fn get_glyph_from_char(self, c: char) -> Option<Glyph> {
-        let mut buffer = [0; 4];
-        let bytes = c.encode_utf8(&mut buffer);
-        for byte in bytes.bytes() {
-            if let Some(glyph) = self.get_glyph(byte) {
-                return Some(glyph);
-            }
-        }
-        None
-    }
-
     /// Supports UTF8 characters
     fn get_first_glyph_from_text(self, text: &str) -> Option<Glyph> {
         if let Some(c) = text.chars().next() {
-            self.get_glyph_from_char(c)
+            Some(self.get_glyph(c))
         } else {
             None
         }
@@ -168,7 +156,7 @@ impl Font {
     /// Supports UTF8 characters
     fn get_last_glyph_from_text(self, text: &str) -> Option<Glyph> {
         if let Some(c) = text.chars().next_back() {
-            self.get_glyph_from_char(c)
+            Some(self.get_glyph(c))
         } else {
             None
         }
@@ -236,27 +224,23 @@ impl Font {
         constant::LINE_SPACE + self.text_height()
     }
 
-    pub fn get_glyph(self, char_byte: u8) -> Option<Glyph> {
-        let gl_data = display::get_char_glyph(char_byte, self.into());
+    pub fn get_glyph(self, ch: char) -> Glyph {
+        let gl_data = display::get_char_glyph(ch as u16, self.into());
 
-        if gl_data.is_null() {
-            return None;
-        }
+        ensure!(!gl_data.is_null(), "Failed to load glyph");
         // SAFETY: Glyph::load is valid for data returned by get_char_glyph
-        unsafe { Some(Glyph::load(gl_data)) }
+        unsafe { Glyph::load(gl_data) }
     }
 
     pub fn display_text(self, text: &str, baseline: Point, fg_color: Color, bg_color: Color) {
         let colortable = get_color_table(fg_color, bg_color);
         let mut adv_total = 0;
-        for c in text.bytes() {
-            let g = self.get_glyph(c);
-            if let Some(gly) = g {
+        for c in text.chars() {
+            let gly = self.get_glyph(c);
             let adv = gly.print(baseline + Offset::new(adv_total, 0), colortable);
             adv_total += adv;
         }
     }
-    }
 
     /// Get the length of the longest suffix from a given `text`
     /// that will fit into the area `width` pixels wide.

core/embed/rust/src/ui/display/mod.rs

@@ -400,8 +400,8 @@ impl<T: AsRef<str>> TextOverlay<T> {
         for g in self
             .text
             .as_ref()
-            .bytes()
-            .filter_map(|c| self.font.get_glyph(c))
+            .chars()
+            .map(|c| self.font.get_glyph(c))
         {
             let top = self.max_height - self.baseline - g.bearing_y;
             let char_area = Rect::new(