diff --git a/src/fontcache.cpp b/src/fontcache.cpp
index 6cdac1fab8..051c4ee1db 100644
--- a/src/fontcache.cpp
+++ b/src/fontcache.cpp
@@ -105,13 +105,13 @@ SpriteFontCache::~SpriteFontCache()
 	this->ClearGlyphToSpriteMap();
 }
 
-SpriteID SpriteFontCache::GetUnicodeGlyph(GlyphID key)
+SpriteID SpriteFontCache::GetUnicodeGlyph(WChar key)
 {
 	if (this->glyph_to_spriteid_map[GB(key, 8, 8)] == nullptr) return 0;
 	return this->glyph_to_spriteid_map[GB(key, 8, 8)][GB(key, 0, 8)];
 }
 
-void SpriteFontCache::SetUnicodeGlyph(GlyphID key, SpriteID sprite)
+void SpriteFontCache::SetUnicodeGlyph(WChar key, SpriteID sprite)
 {
 	if (this->glyph_to_spriteid_map == nullptr) this->glyph_to_spriteid_map = CallocT<SpriteID*>(256);
 	if (this->glyph_to_spriteid_map[GB(key, 8, 8)] == nullptr) this->glyph_to_spriteid_map[GB(key, 8, 8)] = CallocT<SpriteID>(256);
diff --git a/src/gfx_func.h b/src/gfx_func.h
index 3def1c85a4..0ccdabac3d 100644
--- a/src/gfx_func.h
+++ b/src/gfx_func.h
@@ -112,7 +112,7 @@ int DrawString(int left, int right, int top, StringID str, TextColour colour = T
 int DrawStringMultiLine(int left, int right, int top, int bottom, const char *str, TextColour colour = TC_FROMSTRING, StringAlignment align = (SA_TOP | SA_LEFT), bool underline = false, FontSize fontsize = FS_NORMAL);
 int DrawStringMultiLine(int left, int right, int top, int bottom, StringID str, TextColour colour = TC_FROMSTRING, StringAlignment align = (SA_TOP | SA_LEFT), bool underline = false, FontSize fontsize = FS_NORMAL);
 
-void DrawCharCentered(uint32 c, int x, int y, TextColour colour);
+void DrawCharCentered(WChar c, int x, int y, TextColour colour);
 
 void GfxFillRect(int left, int top, int right, int bottom, int colour, FillRectMode mode = FILLRECT_OPAQUE);
 void GfxFillPolygon(const std::vector<Point> &shape, int colour, FillRectMode mode = FILLRECT_OPAQUE);
@@ -164,7 +164,7 @@ void SortResolutions();
 bool ToggleFullScreen(bool fs);
 
 /* gfx.cpp */
-byte GetCharacterWidth(FontSize size, uint32 key);
+byte GetCharacterWidth(FontSize size, WChar key);
 byte GetDigitWidth(FontSize size = FS_NORMAL);
 void GetBroadestDigit(uint *front, uint *next, FontSize size = FS_NORMAL);
 
diff --git a/src/string_type.h b/src/string_type.h
index ced1ab1def..623d74661c 100644
--- a/src/string_type.h
+++ b/src/string_type.h
@@ -32,7 +32,7 @@ enum CharSetFilter {
 };
 
 /** Type for wide characters, i.e. non-UTF8 encoded unicode characters. */
-typedef uint32 WChar;
+typedef char32_t WChar;
 
 /* The following are directional formatting codes used to get the LTR and RTL strings right:
  * http://www.unicode.org/unicode/reports/tr9/#Directional_Formatting_Codes */
diff --git a/src/textbuf_type.h b/src/textbuf_type.h
index a238aa74b5..b4f234f737 100644
--- a/src/textbuf_type.h
+++ b/src/textbuf_type.h
@@ -53,7 +53,7 @@ struct Textbuf {
 	void DeleteAll();
 	bool InsertClipboard();
 
-	bool InsertChar(uint32 key);
+	bool InsertChar(WChar key);
 	bool InsertString(const char *str, bool marked, const char *caret = nullptr, const char *insert_location = nullptr, const char *replacement_end = nullptr);
 
 	bool DeleteChar(uint16 keycode);