On 12/16/2015 09:10 AM, Eli Zaretskii wrote:
> The characters
> will be displayed on any platform, in their text representation, but
> AFAIK Emacs doesn't take color information from the font; the color is
> determined by the color attributes of the face.  We also don't support
> emoji modifiers and emoji variation selectors.

Looking at the code in more detail suggests that it in fact does on Mac, in macfont.m. The relevant bits of code were merged from Macport by Jab Djärv in May of 2014:

    macfont_info->color_bitmap_p = 0;
    if (sym_traits & kCTFontTraitColorGlyphs)
      macfont_info->color_bitmap_p = 1;

and further below

    #if MAC_OS_X_VERSION_MAX_ALLOWED >= 1070
          if (macfont_info->color_bitmap_p
    #if MAC_OS_X_VERSION_MIN_REQUIRED < 1070
              && CTFontDrawGlyphs != NULL
    #endif
              )
            {
              if (len > 0)
                {
                  CTFontDrawGlyphs (macfont_info->macfont, glyphs, positions, len,
                                    context);
                }
            }
          else
    #endif	/* MAC_OS_X_VERSION_MAX_ALLOWED >= 1070 */
            {
              CGContextSetFont (context, macfont_info->cgfont);
              CGContextSetFontSize (context, font_size);
              CGContextShowGlyphsAtPositions (context, glyphs, positions, len);
            }
        }

This seems to be using Apple-specific APIs, however, so it probably does not help much for other platforms. Still, it would be nice to have similar features on GNU/Linux. The patches that allowed this to function on MacOS were small; I wonder if it would be the same on other platforms.