I am new here and have currently no clue, what makes freehand to such an awesome app, that so many people contribute so much love into it, so many years after adobe try to kill it.
There are some nice open source vector drawing apps, which the most of you might already know, like Libreoffice Draw and Inkscape.
Karbon is one more with a public source code, which mainly means that any programmer in the whole world can use the program code of it, like he/she want to do that.
This includes, to write a complete own version.
It is a part of the Calligra office suite and currently not fully ported to Windows and OS X, that is the difficult part of the story.
It use the qt and KDE toolkit and is, with that, in general easy to port to other Systems.
Its UI is very configurable and Krita, the raster based drawing app of Calligra is available on Windows and OS: That prove and means, that a port is doable.
That means of course, that the fundamental library's and more is already ported.
If somebody want to try Karbon on Win/OS X just right now:
Use a Linux based operating system like KaOS in the so called live mode, what means, that the whole OS runs just in RAM, without touching your Hard drive and with that your current OS or other data.
Please use this software in order to write the KaOS ISO on an USB Stick. Be aware, that this method use the full stick, backup all the data on it, before you start to write the OS to it.
If there is no stick around, is it also possible to burn the ISO on DVD: Be aware that you do this with max. 4x burning speed and that a stick performs much quicker and a bit more stable.
Just reboot your computer now and tell your BIOS/UEFI to boot from stick/disk drive, thats it.
Click here, to see the full image:
P.S: If you run into strange issues, is it possible that your ISO get damaged on the download. Please check its integrity then with this software: (Windows)