Emoji TTF font setting not working

[noraj]

Describe the bug

Emoji TTF font setting not working.

To Reproduce

Whatever the TTF font I use from the env. var. or with the option, emojis are not displayed.

# set emoji font in env var
export TEXTIMG_EMOJI_FONT_FILE=/usr/share/fonts/noto/NotoColorEmoji.ttf
export TEXTIMG_EMOJI_FONT_FILE=/usr/share/fonts/joypixels/JoyPixels.ttf
# from env var
echo あ😃a👍！👀ん👄 | ./textimg -i -o emoji.png
# explicit option
echo あ😃a👍！👀ん👄 | ./textimg -i -e /usr/share/fonts/joypixels/JoyPixels.ttf -o emoji.png

Output image:

Expected behavior

Emoji displayed as in the documentation https://github.com/jiro4989/textimg#emoji-font-ttf.

Environment (please complete the following information)

• OS: ArchLinux
• Version: textimg 3.1.7