Updated FAQ about non UTF-8 literal (#609, #613)

imgui.cpp

@@ -411,13 +411,17 @@
       io.Fonts->LoadFromFileTTF("myfontfile.ttf", size_pixels, NULL, &config, io.Fonts->GetGlyphRangesJapanese());
 
  Q: How can I display and input non-Latin characters such as Chinese, Japanese, Korean, Cyrillic?
- A: When loading a font, pass custom Unicode ranges to specify the glyphs to load. ImGui will support UTF-8 encoding across the board.
-    Character input depends on you passing the right character code to io.AddInputCharacter(). The example applications do that.
+ A: When loading a font, pass custom Unicode ranges to specify the glyphs to load. 
+    All strings passed need to use UTF-8 encoding. Specifying literal in your source code using a local code page (such as CP-923 for Japanese CP-1251 for Cyrillic) will not work.
+    In C++11 you can encode a string literal in UTF-8 by using the u8"hello" syntax. Otherwise you can convert yourself to UTF-8 or load text data from file already saved as UTF-8.
+    You can also try to remap your local codepage characters to their Unicode codepoint using font->AddRemapChar(), but international users may have problems reading/editing your source code.
 
       io.Fonts->AddFontFromFileTTF("myfontfile.ttf", size_in_pixels, NULL, io.Fonts->GetGlyphRangesJapanese());  // Load Japanese characters
       io.Fonts->GetTexDataAsRGBA32() or GetTexDataAsAlpha8()
       io.ImeWindowHandle = MY_HWND;      // To input using Microsoft IME, give ImGui the hwnd of your application
 
+    As for text input, depends on you passing the right character code to io.AddInputCharacter(). The example applications do that.
+
  - tip: the construct 'IMGUI_ONCE_UPON_A_FRAME { ... }' will run the block of code only once a frame. You can use it to quickly add custom UI in the middle of a deep nested inner loop in your code.
  - tip: you can create widgets without a Begin()/End() block, they will go in an implicit window called "Debug"
  - tip: you can call Begin() multiple times with the same name during the same frame, it will keep appending to the same window. this is also useful to set yourself in the context of another window (to get/set other settings)

imgui.h

@@ -1262,7 +1262,7 @@ struct ImFontAtlas
     void                        SetTexID(void* id)  { TexID = id; }
 
     // Helpers to retrieve list of common Unicode ranges (2 value per range, values are inclusive, zero-terminated list)
-    // (Those functions could be static but aren't so most users don't have to refer to the ImFontAtlas:: name ever if in their code; just using io.Fonts->)
+    // NB: Make sure that your string are UTF-8 and NOT in your local code page. See FAQ for details.
     IMGUI_API const ImWchar*    GetGlyphRangesDefault();    // Basic Latin, Extended Latin
     IMGUI_API const ImWchar*    GetGlyphRangesKorean();     // Default + Korean characters
     IMGUI_API const ImWchar*    GetGlyphRangesJapanese();   // Default + Hiragana, Katakana, Half-Width, Selection of 1946 Ideographs