Textinput does not render emojis correctly

[RobinPicard]

Software Versions

• Python: 3.9
• OS: MacOS BigSur 11.4
• Kivy: v2.2.0.dev0
• Kivy installation method: development

Describe the bug
The textinput widgets render the colored emojis as completely black contrarily to labels that render them corrected

Expected behavior
The emojis should be colored

To Reproduce

from kivy.core.window import Window
from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.textinput import TextInput

Window.clearcolor = (1, 1, 1, 1)

class CustomBoxLayout(BoxLayout):
    def __init__(self, *args):
        super().__init__(*args)
        self.a_textinput = TextInput(background_normal='', font_name='NotoColorEmoji.ttf')
        self.a_label = Label(font_name='NotoColorEmoji.ttf')
        self.add_widget(self.a_textinput)
        self.add_widget(self.a_label)
        self.a_textinput.bind(text=self.update_label)

    def update_label(self, instance, text, *args):
        self.a_label.text = text

class MyApp(App):
    def build(self):
        return CustomBoxLayout()

if __name__ == '__main__':
    MyApp().run()

Code and Logs and screenshots

Additional context
I think I found the origin of the problem, I will open a PR shortly

[Julian-O]

@RobinPicard: Just a ping to see how you are going with the PR review comments.

[Julian-O]

Related #7565

[RobinPicard]

@RobinPicard: Just a ping to see how you are going with the PR review comments.

I'm not working on Kivy-related things anymore, sorry

[Julian-O]

To others reading this, we have a partially implemented PR, with review comments, that needs a volunteer to rebase, address the comments, and commit a new PR.. Could be an easy way to earn Internet points.

[Julian-O]

@DexerBR has stepped forward with #8491. Thank you muchly!