Quick Grayscale lets you easily toggle mac's grayscale mode from the status bar. It's a wrapper around couple of Applescripts that automate the process of going in settings and toggling the "Use Grayscale" checkbox (since Apple doesn't provide any API to handle it programmatically). To download the application, head here.
Quick Grayscale has been developed with RUMPS library which is a wrapper over PyObjC. To run it, install all dependencies via:
pip3 install -r requirements.txt
and then, run the main source file:
The application package can be build by using py2app.
python3 setup.py py2app
To create a DMG bundle, I have used create-dmg.
create-dmg dist/QuickGrayscale.app/ dist/