Hi,
The last parameter of 'imgui_add_ttf_from_file' is a ImGui preset of ranges of glyphs. For full chinesse should be 1, and for simplified 2. You can find the defines at 'imgui_helpers.h'.

You can build yor own glyph ranges with 'imgui_add_ttf_from_file_ranged' where the last parameter is an array of shorts with all the ranges from unicode table ended with a null entry.

The array should look something like this:
Code
short  myGlyphRanges[7] = {
   30, 127,            // Latin1 basic
   2087, 3048,      // Imaginary range as example
   16524, 16524,  // A single character range
   0                       // array ended with a null entry
}
...
imgui_add_ttf_from_file_ranged("myFont.ttf", 16, myGlyphRanges);


I did not try with chinesse, but cyrillic was working perfectly.

The glyph range of my main project looks like the following. I included all the latin characters, some of the symbols and a piece of the private area:
Code
short glyphRanges[23] = {
//	0x0000, 0x001F, // Control characters
	0x0020, 0x007F, // Basic Latin
//	0x0080, 0x00FF, // Latin supplement
		0x00A0, 0x00FF,
	0x0100, 0x017F, // Latin extended-A
	0x0180, 0x024F, // Latin extended-B
//	0x02B0, 0x02FF, // Spacing modifier letters
		0x02C0, 0x02DF,
//	0x2000, 0x206F, // General punctuation
		0x2010, 0x2027,
		0x2030, 0x205E,
//	0x20A0, 0x20CF, // Currency symbols
		0x20AC, 0x20AC,
//	0x2100, 0x214F, // Letterlike symbols
		0x2122, 0x2122,
//	0x2600, 0x26FF, // Miscellaneous symbols
		0x2600, 0x2647,
//	0xE800, 0xE8FF, // Private use area
		0xE800, 0xE808,
	0
};


I used hexadecimal notation because it is the common way to refer to unicode characters

I hope it helps,
Salud!