Internals: Added ImTextCharToUtf8() helper. Added "out_" markers in more UTF-8 functions. Metrics: Fonts: Fixed display of EllipsisChar by feeding proper utf-8.

imgui.cpp

@@ -1701,7 +1701,7 @@ int ImTextCountCharsFromUtf8(const char* in_text, const char* in_text_end)
 }
 
 // Based on stb_to_utf8() from github.com/nothings/stb/
-static inline int ImTextCharToUtf8(char* buf, int buf_size, unsigned int c)
+static inline int ImTextCharToUtf8_inline(char* buf, int buf_size, unsigned int c)
 {
     if (c < 0x80)
     {
@@ -1736,6 +1736,13 @@ static inline int ImTextCharToUtf8(char* buf, int buf_size, unsigned int c)
     return 0;
 }
 
+const char* ImTextCharToUtf8(char out_buf[5], unsigned int c)
+{
+    int count = ImTextCharToUtf8_inline(out_buf, 5, c);
+    out_buf[count] = 0;
+    return out_buf;
+}
+
 // Not optimal but we very rarely use this function.
 int ImTextCountUtf8BytesFromChar(const char* in_text, const char* in_text_end)
 {
@@ -1752,20 +1759,20 @@ static inline int ImTextCountUtf8BytesFromChar(unsigned int c)
     return 3;
 }
 
-int ImTextStrToUtf8(char* buf, int buf_size, const ImWchar* in_text, const ImWchar* in_text_end)
+int ImTextStrToUtf8(char* out_buf, int out_buf_size, const ImWchar* in_text, const ImWchar* in_text_end)
 {
-    char* buf_out = buf;
-    const char* buf_end = buf + buf_size;
-    while (buf_out < buf_end - 1 && (!in_text_end || in_text < in_text_end) && *in_text)
+    char* buf_p = out_buf;
+    const char* buf_end = out_buf + out_buf_size;
+    while (buf_p < buf_end - 1 && (!in_text_end || in_text < in_text_end) && *in_text)
     {
         unsigned int c = (unsigned int)(*in_text++);
         if (c < 0x80)
-            *buf_out++ = (char)c;
+            *buf_p++ = (char)c;
         else
-            buf_out += ImTextCharToUtf8(buf_out, (int)(buf_end - buf_out - 1), c);
+            buf_p += ImTextCharToUtf8_inline(buf_p, (int)(buf_end - buf_p - 1), c);
     }
-    *buf_out = 0;
-    return (int)(buf_out - buf);
+    *buf_p = 0;
+    return (int)(buf_p - out_buf);
 }
 
 int ImTextCountUtf8BytesFromStr(const ImWchar* in_text, const ImWchar* in_text_end)
@@ -11459,8 +11466,9 @@ void ImGui::DebugNodeFont(ImFont* font)
         "You can also render at multiple sizes and select which one to use at runtime.\n\n"
         "(Glimmer of hope: the atlas system will be rewritten in the future to make scaling more flexible.)");
     Text("Ascent: %f, Descent: %f, Height: %f", font->Ascent, font->Descent, font->Ascent - font->Descent);
-    Text("Fallback character: '%c' (U+%04X)", font->FallbackChar, font->FallbackChar);
-    Text("Ellipsis character: '%c' (U+%04X)", font->EllipsisChar, font->EllipsisChar);
+    char c_str[5];
+    Text("Fallback character: '%s' (U+%04X)", ImTextCharToUtf8(c_str, font->FallbackChar), font->FallbackChar);
+    Text("Ellipsis character: '%s' (U+%04X)", ImTextCharToUtf8(c_str, font->EllipsisChar), font->EllipsisChar);
     const int surface_sqrt = (int)ImSqrt((float)font->MetricsTotalSurface);
     Text("Texture Area: about %d px ~%dx%d px", font->MetricsTotalSurface, surface_sqrt, surface_sqrt);
     for (int config_i = 0; config_i < font->ConfigDataCount; config_i++)

imgui_internal.h

@@ -322,12 +322,13 @@ static inline bool      ImCharIsBlankA(char c)          { return c == ' ' || c =
 static inline bool      ImCharIsBlankW(unsigned int c)  { return c == ' ' || c == '\t' || c == 0x3000; }
 
 // Helpers: UTF-8 <> wchar conversions
-IMGUI_API int           ImTextStrToUtf8(char* buf, int buf_size, const ImWchar* in_text, const ImWchar* in_text_end);      // return output UTF-8 bytes count
-IMGUI_API int           ImTextCharFromUtf8(unsigned int* out_char, const char* in_text, const char* in_text_end);          // read one character. return input UTF-8 bytes count
-IMGUI_API int           ImTextStrFromUtf8(ImWchar* buf, int buf_size, const char* in_text, const char* in_text_end, const char** in_remaining = NULL);   // return input UTF-8 bytes count
-IMGUI_API int           ImTextCountCharsFromUtf8(const char* in_text, const char* in_text_end);                            // return number of UTF-8 code-points (NOT bytes count)
-IMGUI_API int           ImTextCountUtf8BytesFromChar(const char* in_text, const char* in_text_end);                        // return number of bytes to express one char in UTF-8
-IMGUI_API int           ImTextCountUtf8BytesFromStr(const ImWchar* in_text, const ImWchar* in_text_end);                   // return number of bytes to express string in UTF-8
+IMGUI_API const char*   ImTextCharToUtf8(char out_buf[5], unsigned int c);                                                      // return out_buf
+IMGUI_API int           ImTextStrToUtf8(char* out_buf, int out_buf_size, const ImWchar* in_text, const ImWchar* in_text_end);   // return output UTF-8 bytes count
+IMGUI_API int           ImTextCharFromUtf8(unsigned int* out_char, const char* in_text, const char* in_text_end);               // read one character. return input UTF-8 bytes count
+IMGUI_API int           ImTextStrFromUtf8(ImWchar* out_buf, int out_buf_size, const char* in_text, const char* in_text_end, const char** in_remaining = NULL);   // return input UTF-8 bytes count
+IMGUI_API int           ImTextCountCharsFromUtf8(const char* in_text, const char* in_text_end);                                 // return number of UTF-8 code-points (NOT bytes count)
+IMGUI_API int           ImTextCountUtf8BytesFromChar(const char* in_text, const char* in_text_end);                             // return number of bytes to express one char in UTF-8
+IMGUI_API int           ImTextCountUtf8BytesFromStr(const ImWchar* in_text, const ImWchar* in_text_end);                        // return number of bytes to express string in UTF-8
 
 // Helpers: ImVec2/ImVec4 operators
 // We are keeping those disabled by default so they don't leak in user space, to allow user enabling implicit cast operators between ImVec2 and their own types (using IM_VEC2_CLASS_EXTRA etc.)