Add API & document: show keyboard layout for input methods

Number:rdar://39296952 Date Originated:2018/4/10
Status: Resolved:
Product:macOS + SDK, Keyboards, mice and trackpads Product Version:
Classification: Reproducible:
Although default bundled input methods show keyboard layout within System Preferences, 3rd party input methods cannot show its.

To provide a consistent user experience, it is good to allow 3rd party input methods to show keyboard layout.

Steps to Reproduce:

Expected Results:
Add API to InputMethodKit to display keyboard layout at System Preferences.

Actual Results:
There is no such API, and relations between  input method and keyboard layout is hard coded in a `/System/Library/PreferencePanes/Keyboard.prefPane/Contents/Resources/IntlKeyboard.prefPane`.

macOS High Sierra / 10.13.4 (17E199)



Please note: Reports posted here will not necessarily be seen by Apple. All problems should be submitted at before they are posted here. Please only post information for Radars that you have filed yourself, and please do not include Apple confidential information in your posts. Thank you!