Support international languages

[Julian-O]

There are a large number of issues logged in Kivy related to Internationalization (I18N) - particularly support for non-English languages. This is an attempt to bring them together in one place, so we can see what work still needs to be done.

I am aware there are already efforts underway to tackle some of these issues, and I don't expect them all to be solved in one PR.

This can be used to close some of the duplicate issues, but other issues I plan to leave open to handle the discussion of particular details and testing.

In order to support international language, we must support both displaying the language and text entry. [For the purposes of this request, I am treating Emoji as a language.]

Here is a collection of issues:

• Displaying the language:

  • Displaying Unicode

    • Emoji widths calculated wrongly Certain Unicode characters not affecting the label size #4130
    • pygame and SDL2 truncate some Unicode characters Unicode codepoint truncation #2761
    • Truncated text Sinhala letters are not complete in some places in kivy Label and sinhala font in kivy TextInput is wrong #8182
    • Reshaping letters
      • Language not being reshaped properly Rendering Hindi(Indian) Language Wrong in Kivy for Android App  #7149
      • Language not being reshaped properly Issues with printing languages in unicode. #2669
      • Language not being reshaped properly Kivy label show Khmer error #7227

  • Can't display Unicode to console on Android Unicode console printing #2345

  • Glyph fallback when the preferred font doesn't include a character

    • Need glyph fallback CJK support #6790
    • Wants system font, needs glyph fallback [Android] Is it possible to use system-provided fonts? #6106
    • Unicode tofu (ie. no glyph fallback) when displaying emoji TextInput rendering certain characters as boxes #4741
    • Request for glyph fallback, without using that term; Manage Fonts list and character recognition fallback in a platform independent manner. #1701

  • Colour emojis appear in monotone Allow Original color of emoji font in Label #7565

  • Both left-to-right and right-to-left languages

    • Support RTL languages Feature Request: right to left support for TextInput #1619 Arabic and RTL support #7704 Arabic text should be supported prefectly #8316 Kivy does not support RTL #8001

• Text entry

  • Prototype to improve many of these issues: Treat textinput as a provider [WIP] [build wheel] Introduce TextInput provider (Android, iOS and "Legacy" Window provider) #8226
  • Can't select keyboard that supports regional language on Android Kivy Text Input Field not accepting all android keyboards (like handwriting, regional language ) and not displaying multi language Unicode text #7741
  • Can't select keyboard that supports regional language on Android or IOS kivy on ios and android keyborad IME #5739
  • Can select keyboard that supports regional language on Android but still get English characters When typing Sinhala language from Gboard (Google Keyboard), English language is typed instead of Sinhala in TextInput. #8185
  • Unclear, but having trouble typing Vietnamese Android - Textinput can't type Unicode. #7294
  • Can select different keyboard, but setting is forgotten Keyboard won't save input language preference #7184
  • Doesn't use phone's native keyboard in Android Keyboard not same as in all other apps in android #7053
  • Don't get partial characters entering on IME keyboard IME input left arrow key causing incorrect insertion #6898
  • Can't enter regional language in TextInput Chinese Input Broken on iOS device #4079
  • Delete key deletes whole character rather than partial the delete key behavior error when using the Chinese input method (输中文过程中delete键会删掉文本中的内容) #6532
  • Missing keycodes for non-ASCII keyboards Various keyboard keys issues (missing, invalid or both) #5127
  • Emoji appear as black silhouettes during entry Textinput does not render emojis correctly #7995
  • No hints when using non-English keyboard How to popup the selection box when typing #6520
  • Can't enter unicode characters Can't type special characters into TextInput #3459

• Unicode in code

  • Can't load an image with Unicode filename code/img_imageio encoding issue #3489

[ElliotGarbus]

This article has been helpful for a number of users: https://medium.com/@ahmedfgad/supporting-arabic-alphabet-in-kivy-for-building-cross-platform-applications-7a1e7c14a068

[Julian-O]

This article has been helpful for a number of users:

Nice! That's going straight into the FAQ! (which I am about to edit)