I tried to add
Noto Color Emoji from Google Noto as my font for Emoji in GNU Emacs, as mentioned in here, but for some reason GNU Emacs doesn't display these characters properly in its window. I'm using GNU Emacs 24.5.1 on GNU/Linux. Is this a bug or am I doing something wrong?
I tried to add
You're not doing anything wrong.
Emacs for Linux uses XFT for font rendering, and XFT doesn't yet support the color fonts. See this mailing list thread from Dec 2015. Richard Stallman writes in that thread that it's a low priority and they don't care about color fonts. Also in that thread you can see that they disabled color fonts in Emacs for Mac, not for any technical reason but because color fonts are not supported in the Unix version of Emacs and they don't want the Mac version to have a feature that is not in the Unix version.
So I wouldn't expect to see this any time soon.
Or you can use Emacs terminal (
emacs -nw) on a terminal emulator that support color emoji.
Emacs can be run as GUI or terminal application. To start emacs terminal, open your terminal emulator (iTerm or iTerm2 in MacOS, Mate-Terminal or Gnaome-Terminal in Linux) and run the command
emacs -nw in the terminal emulator. When running in terminal mode, the glyphs and fonts are not in control of Emacs and it must display what the terminal emulator is giving. With a terminal that support color emojis, you can force Emacs terminal to display them.