programming question

I asked this on /tech/ but nobody was able to respond. Can anyone here help?

How would you make a 'multimedia document' viewer from scratch in linux?

I know a fair bit of programming but I don't know how this would be done and I really want to do it.

I want to create something that can display a simple markup language (A bit like .md) that includes text, images, buttons and user input forms.

I know how to parse the language into an AST but then how do I lay it out graphically in such a way that users can select text out of it to copy and also resize the window.

here's the bookmarklet to make /prog/ into an imageboard. can upload using ipfs.pics

var all = document.getElementsByTagName("a"); for (var i = 0, x; x = all[i++];) { if(x['href'].substring(0,8) === 'ipfs:///' && x.parentElement.nodeName == 'SAMP') { var im = document.createElement("img"); im.setAttribute('src', 'http://ipfs.io/ipfs/'+x['href'].substring(8)); x.parentElement.replaceChild(im,x); } }

bookmark this: javascript:(function(){var all = document.getElementsByTagName("a"); for (var i = 0, x; x = all[i++];) { if(x['href'].substring(0,8) === 'ipfs:///' && x.parentElement.nodeName == 'SAMP') { var im = document.createElement("img"); im.setAttribute('src', 'http://ipfs.io/ipfs/'+x['href'].substring(8)); x.parentElement.replaceChild(im,x); } }})();