diff --git a/imgui/src/fonts/atlas.rs b/imgui/src/fonts/atlas.rs
index 7f49fd5..537e4d1 100644
--- a/imgui/src/fonts/atlas.rs
+++ b/imgui/src/fonts/atlas.rs
@@ -357,7 +357,8 @@ impl FontConfig {
         raw.GlyphMaxAdvanceX = self.glyph_max_advance_x;
         raw.FontBuilderFlags = self.font_builder_flags;
         raw.RasterizerMultiply = self.rasterizer_multiply;
-        raw.EllipsisChar = self.ellipsis_char.map(|x| x as u16).unwrap_or(0xffff);
+        // char is used as "unset" for EllipsisChar
+        raw.EllipsisChar = self.ellipsis_char.map(|c| c as u32).unwrap_or(!0);
         if let Some(name) = self.name.as_ref() {
             let bytes = name.as_bytes();
             let mut len = bytes.len().min(raw.Name.len() - 1);
diff --git a/imgui/src/fonts/font.rs b/imgui/src/fonts/font.rs
index e401b5b..fcb3317 100644
--- a/imgui/src/fonts/font.rs
+++ b/imgui/src/fonts/font.rs
@@ -24,7 +24,7 @@ pub struct Font {
     pub ascent: f32,
     pub descent: f32,
     pub metrics_total_surface: c_int,
-    pub used_4k_pages_map: [u8; 2],
+    pub used_4k_pages_map: [u8; 34],
 }
 
 unsafe impl RawCast<sys::ImFont> for Font {}
diff --git a/imgui/src/fonts/glyph_ranges.rs b/imgui/src/fonts/glyph_ranges.rs
index dcadeb0..b22ae50 100644
--- a/imgui/src/fonts/glyph_ranges.rs
+++ b/imgui/src/fonts/glyph_ranges.rs
@@ -13,7 +13,7 @@ enum FontGlyphRangeData {
     Custom(*const sys::ImWchar),
 }
 
-/// A set of 16-bit Unicode codepoints
+/// A set of Unicode codepoints
 #[derive(Clone, Eq, PartialEq, Debug)]
 pub struct FontGlyphRanges(FontGlyphRangeData);
 impl FontGlyphRanges {
@@ -51,7 +51,7 @@ impl FontGlyphRanges {
     }
 
     /// Creates a glyph range from a static slice. The expected format is a series of pairs of
-    /// non-zero shorts, each representing an inclusive range of codepoints, followed by a single
+    /// non-zero codepoints, each representing an inclusive range, followed by a single
     /// zero terminating the range. The ranges must not overlap.
     ///
     /// As the slice is expected to last as long as a font is used, and is written into global
@@ -61,7 +61,12 @@ impl FontGlyphRanges {
     /// ======
     ///
     /// This function will panic if the given slice is not a valid font range.
-    pub fn from_slice(slice: &'static [u16]) -> FontGlyphRanges {
+    // TODO(thom): This takes `u32` for now, since I believe it's fine for it to
+    // contain surrogates? (It seems plausible that font data can describe what
+    // to show for unpaired surrogates) Would be nice to be sure, if so, this
+    // should accept `char` (we'd still have to check that the range doesn't
+    // fully contain the surrogate range though)
+    pub fn from_slice(slice: &'static [u32]) -> FontGlyphRanges {
         assert_eq!(
             slice.len() % 2,
             1,
@@ -79,7 +84,14 @@ impl FontGlyphRanges {
                 "A glyph in a range cannot be zero. \
                  (Glyph is zero at index {})",
                 i
-            )
+            );
+            assert!(
+                glyph <= core::char::MAX as u32,
+                "A glyph in a range cannot exceed the maximum codepoint. \
+                 (Glyph is {:#x} at index {})",
+                glyph,
+                i,
+            );
         }
 
         let mut ranges = Vec::new();
@@ -118,7 +130,7 @@ impl FontGlyphRanges {
     /// # Safety
     ///
     /// It is up to the caller to guarantee the slice contents are valid.
-    pub unsafe fn from_slice_unchecked(slice: &'static [u16]) -> FontGlyphRanges {
+    pub unsafe fn from_slice_unchecked(slice: &'static [u32]) -> FontGlyphRanges {
         FontGlyphRanges::from_ptr(slice.as_ptr())
     }
 
@@ -130,7 +142,7 @@ impl FontGlyphRanges {
     ///
     /// It is up to the caller to guarantee the pointer is not null, remains valid forever, and
     /// points to valid data.
-    pub unsafe fn from_ptr(ptr: *const u16) -> FontGlyphRanges {
+    pub unsafe fn from_ptr(ptr: *const u32) -> FontGlyphRanges {
         FontGlyphRanges(FontGlyphRangeData::Custom(ptr))
     }
 
diff --git a/imgui/src/io.rs b/imgui/src/io.rs
index 440984d..8bc6238 100644
--- a/imgui/src/io.rs
+++ b/imgui/src/io.rs
@@ -334,9 +334,25 @@ impl Io {
     }
     /// Peek character input buffer, return a copy of entire buffer
     pub fn peek_input_characters(&self) -> String {
-        let c16_slice = self.input_queue_characters.as_slice();
-        String::from_utf16(c16_slice).unwrap()
+        self.input_queue_characters().collect()
     }
+
+    /// Returns a view of the data in the input queue (without copying it).
+    ///
+    /// The returned iterator is a simple mapping over a slice more or less what
+    /// you need for random access to the data (Rust has no
+    /// `RandomAccessIterator`, or we'd use that).
+    pub fn input_queue_characters(
+        &self,
+    ) -> impl Iterator<Item = char> + DoubleEndedIterator + ExactSizeIterator + Clone + '_ {
+        self.input_queue_characters
+            .as_slice()
+            .iter()
+            // TODO: are the values in the buffer guaranteed to be valid unicode
+            // scalar values? if so we can just expose this as a `&[char]`...
+            .map(|c| core::char::from_u32(*c).unwrap_or(core::char::REPLACEMENT_CHARACTER))
+    }
+
     pub fn update_delta_time(&mut self, delta: Duration) {
         let delta_s = delta.as_secs() as f32 + delta.subsec_nanos() as f32 / 1_000_000_000.0;
         if delta_s > 0.0 {