Key Mapping for specific apps in Mac

20 Jun 2018

Scenario: Keymapping for specific apps in Mac.

For example, Windows and Mac use control/ command keys differently, it becomes annoying when using Microsoft Remote Desktop on Mac doesn’t provide a self-contained working environment, it often jumps to other mac apps easily. Map the mac command key to control key sort out the problem.

Download Karabiner (source code).

After installation, allow this 3rd party app to make system changes: System Preferences > Security & Privacy button > Allow. If not working, try close Chrome and MagicPrefs if installed. cc steps.
In order to map keys only for specific apps, we need the app bundle ID: Go to the application folder (e.g. /Applications/) mdls -name kMDItemCFBundleIdentifier -r Microsoft\ Remote\ Desktop\ Beta.app Then got "com.microsoft.rdc.osx.beta"
Create a new json script under ~/.config/karabiner/assets/complex_modifications/, Here is my sample.json:

{
  "title": "Remote Desktop new",
  "rules": [
    {
      "description": "Map left command to left control",
      "manipulators": [
        {
          "type": "basic",
          "from": {
            "key_code": "left_gui",
            "modifiers": {
              "optional": [
                "any"
              ]
            }
          },
          "to": [
            {
              "key_code": "left_control"
            }
          ],
          "conditions": [
            {
              "type": "frontmost_application_if",
              "bundle_identifiers": [
                "com\\.microsoft\\.rdc\\.osx\\.beta"
              ]
            }
          ]
        }
        
      ]
    }
  ]
}

The new rule should pop in the perference/ complex modification tab:
Enable the new rule:
Debug: Karabiner has a handy tool Karabiner-EventViewer to track all inputs, check the eventType of the desired keys; and bundle names mentioned in the previous step. Also disable/ enable the new rules to make sure it’s applied.

Numeric Jungle

Key Mapping for specific apps in Mac