The Fonts have their own folders in the "koreader" directory. You could try adding your fonts to the appropriate folder. I have added a number of .ttf fonts to the "freefont" folder. It has been a while since I did this for the android version (I broke my tablet), but as I remember it I just put them into the download .apk (along with some other changes) then signed the modified .apk (using EasyApkDisassembler.V1.3.2). Those .apk installed fine on my old tablet.
Luck;
Ken
|