SizeUp is a window manager app like the others. It costs $12.99 at the time of writing, but offers unlimited free trial (it just reminds you every now and then to pay).
SizeUp allows you to quickly resize and position your windows with keyboard shortcuts or a handy menu bar icon.
It is not open source, though.
If you want a more powerful alternative to Rectangle, you could use the free and open-soure Yabai, which you can configure however you like.
yabai is a window management utility that is designed to work as an extension to the built-in window manager of macOS. yabai allows you to control your windows, spaces and displays freely using an intuitive ...
You can use Rectangle to achieve this for free.
Rectangle is a window management app based on Spectacle, written in Swift.
After downloading, installing, and granting the app accessibility permissions in System Preferences, you'll be able to enable the default keyboard shortcut scheme, which allows you to press ctrl + opt + U/I/K/J to snap a ...
An app you might want to check is BetterSnapTool. It does what you want and is available from the Mac App Store. It sells for $2.99. I know you wanted a free app but I couldn't find one for the Mac.
BetterSnapTool allows you to easily manage your window positions and sizes by either dragging them to one of your screens corners or to the top, ...
Thanks to the keyword "Airplay", that Morgan Rogers dropped, I found another way I want to document here (but maybe someone still has a better idea ;-) ):
I remembered there was an app called X-Mirage that works as an airplay receiver app for MacOS. So I can set up X-Mirage as a Airplay receiver and send from the iPad from any sketching App I ...
I know that this is an old question, but by the end of 2020 there is a really nice open source utility — iGlance. Just tried it and it seems to work really fine. There are some minor issues with appearance under some circumstances, but otherwise it is very solid.
The best tool I have found for this is the iPad app Notability (I am not affiliated, I am a math professor who is also giving all lectures on Zoom). When I share the screen in Zoom (on my Mac), I am able to select "iPad over AirPlay" as the source for the share.
Notability has a "presentation mode" where you can see the UI to select ...