Docs for harfbuzz-ng or API details
harfbuzz
Solution
Some good and simple examples are listed on Harfbuzz wiki, 1, 2
I suggest you a higher level library, Pango if you need layout things like line wrap and I guess you would find better doucmentation for it than HarfBuzz itself.
You may have a look at State of Text Rendering also.
Problem
I was working on harbuzz old one. now a new version of harbuzz-ng has came. now this structure is completely changes in comparison of old code. Without API docs its really hard to work/use this library. I google about it but didnot find any relavent details. How can i start using it. Any test program to understand the input and output for this library. If anybody have a test /hello world type from or any reference docs for API please share.