├── readme.md
└── latexrender.lua


/readme.md:
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 1 | ## Whatisit ?
 2 | A way to have Latex rendered inside nvim 
 3 | 
 4 | ## Example
 5 | ![fig](https://user-images.githubusercontent.com/58146965/224890491-c4fbb91e-f366-4790-994d-87bf51bba7ee.png)
 6 | 
 7 | 
 8 | ## Requirements
 9 | * Requires [hologram.nvim](https://github.com/edluffy/hologram.nvim) setup.
10 | * Only works in [kitty](https://sw.kovidgoyal.net/kitty/)
11 | * You must have texlive with `dvipng` binary on your system.
12 |   if you're on Arch , [texlive-bin](https://archlinux.org/packages/extra/x86_64/texlive-bin/) should suffice
13 | * Only works on linux (ymmv on mac , and erm Windows)
14 | 
15 | ## How to use ?
16 | 
17 | ### Install
18 | It's fairly bairbones as of now , 
19 | copy latexrenderer.lua into your computer and load it 
20 | with `luafile /path/to/latexrenderer.lua` in your init.vim .
21 | 
22 | I'll (hopefully) make this a plugin someday , but for now i'm mostly trying
23 | out things for myself.
24 | 
25 | ### Render all math
26 | If succesfully loaded you should have two commands 
27 | `RenderLatex <size>` , which will scan through your buffer,
28 | treating everything between pairs of `$$` as Latex and render it below that line ( does not support inline math), `<size>` specifies the size of the png to render
29 | 
30 | ### Render math at cursor
31 | If the cursor is at an equation you can render the current equation only with `RenderLatexAtCursor <size>`. 
32 | 
33 | ### Remove all renderings
34 | `RemoveLatex` will remove the rendered pngs
35 | 
36 | ## Bugs
37 | For some reason the math cant be the first or the last line :( ,
38 | 
39 | ## Misc
40 | Colors are hardcoded (for fg of gruvbox dark) , you can change it in the line (`-fg 'cmyk 0.00 0.04 0.21 0.02'`) where dvipng is called.
41 | 


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/latexrender.lua:
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  1 | local vim = vim
  2 | 
  3 | function printtable(t)
  4 |   --for debug
  5 |   for k,v in pairs(t) do
  6 |     print(k,v)
  7 |   end
  8 | end
  9 | 
 10 | function counttable(t)
 11 |   --returns number of elements in table
 12 |   count=0
 13 |   for _ in pairs(t) do
 14 |     count=count+1
 15 |   end
 16 |   return count
 17 | end
 18 | 
 19 | local random = math.random
 20 | math.randomseed(os.time())
 21 | local function uuid()
 22 |     local template ='xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'
 23 |     return string.gsub(template, '[xy]', function (c)
 24 |         local v = (c == 'x') and random(0, 0xf) or random(8, 0xb)
 25 |         return string.format('%x', v)
 26 |     end)
 27 | end
 28 | 
 29 | 
 30 | function find_equations()
 31 |   --returns a list , every element of list is table {lno,cno} pair 
 32 |   lines = vim.api.nvim_buf_get_lines(0,0,-1,false)
 33 |   positions = {}
 34 |   -- read through all of them 
 35 |   for lno,line in pairs(lines) do
 36 |     st = 1
 37 |     while true do
 38 |       local x,y=string.find(line,"$$",st,true)
 39 |       if x==nil then break end
 40 |       table.insert(positions,{lno,x})
 41 |       st=y+1
 42 |     end
 43 |   end
 44 |   if (counttable(positions)%2)~=0 then
 45 |     print("unmatched $$")
 46 |   end
 47 |   return positions
 48 | end
 49 | 
 50 | function iszeropos(pos)
 51 |   return (pos[1] == 0 and  pos[2] == 0)
 52 | end
 53 | 
 54 | function latex_topng(fnames,size)
 55 |   --renders the latex as png's  in /tmp
 56 |   latexjobids = {}
 57 |   dvijobids = {}
 58 |   for k,fname in pairs(fnames) do
 59 |     jobid = vim.fn.jobstart("latex  --interaction=nonstopmode --output-dir=/tmp --output-format=dvi LATEXFILE" .. fname, {cwd="/tmp",on_stdout = function (j,d,e) print() end,on_stderr=function (j,d,e) print() end})
 60 |     table.insert(latexjobids,jobid)
 61 |   end
 62 |   vim.fn.jobwait(latexjobids)
 63 |   for k,fname in pairs(fnames) do
 64 |     jobid = vim.fn.jobstart("dvipng -D "..tonumber(size).. " -T tight  -bg Transparent -fg 'cmyk 0.00 0.04 0.21 0.02'  -o /tmp/LATEXFILE"..fname..".png".." ".."/tmp/LATEXFILE"..fname..".dvi",{cwd="/tmp",on_stdout = function (j,d,e) print() end})
 65 |     table.insert(dvijobids,jobid)
 66 |   end
 67 |   vim.fn.jobwait(dvijobids)
 68 | end
 69 | 
 70 | function get_lstrings(positions)
 71 |   --gets list os strings between positions 
 72 |   --positions is a list of pairs of lno,cno  (lineno , columno)
 73 |   lstrings = {}
 74 |   for i=1,counttable(positions),2 do
 75 |     lstring = ""
 76 |     start = positions[i]
 77 |     stop = positions[i+1]
 78 |     for k,v in pairs(vim.api.nvim_buf_get_text(0,start[1]-1,start[2]+1,stop[1]-1,stop[2]-1,{nil})) do
 79 |       lstring = lstring .. v
 80 |     end
 81 |     table.insert(lstrings,lstring)
 82 |   end
 83 |   return lstrings
 84 | end
 85 | local pre = "\\documentclass[12pt]{standalone}\n \\usepackage{amsmath}\n \\usepackage{amssymb} \n \\begin{document}\n \\begin{align} "
 86 | local post = "\\end{align} \n \\end{document}"
 87 | 
 88 | function write_texfiles(lstrings)
 89 |   fnames = {}
 90 |   for k,v in pairs(lstrings) do
 91 |     fname = uuid()
 92 |     filehandle = io.open("/tmp/LATEXFILE"..fname, "w")
 93 |     filehandle:write(pre..v.."\n"..post)
 94 |     filehandle:close()
 95 |     table.insert(fnames,fname)
 96 |   end
 97 |   return fnames
 98 | end
 99 | 
100 | local imgs = {}
101 | function insertpngs(eqpos,fnames,size)
102 |   findex = 1
103 |   for i=1,counttable(eqpos),2 do
104 |     source = "/tmp/LATEXFILE"..fnames[findex]..".png"
105 |     buf = vim.api.nvim_get_current_buf()
106 |     table.insert(imgs,require('hologram.image'):new(source, {}))
107 |     imgs[findex]:display(eqpos[i+1][1], 0, buf, {})
108 |     findex = findex+1
109 |   end
110 | end
111 | 
112 | function RenderLatex(opts)
113 |   RemoveLatex()
114 |   eqpos = find_equations()
115 |   lstrings = get_lstrings(eqpos)
116 |   fnames = write_texfiles(lstrings)
117 |   latex_topng(fnames,opts.fargs[1])
118 |   insertpngs(eqpos,fnames)
119 | end
120 | 
121 | function inbetween(curpos,pos1,pos2)
122 |   --checks if curpos is b/w pos1 and pos2
123 |   --assumes pos2 isafter pos1
124 |   if pos1[1]==pos2[1] then
125 |     --is pos1 and pos2 on same line, check column
126 |     if curpos[1]==pos1[1] and pos1[2]<curpos[2] and curpos[2]<pos2[2]  then
127 |       return true
128 |     end
129 |   elseif pos1[1]==curpos[1] and pos1[2] < curpos[2] then
130 |     -- now that we established pos1 and pos2 are on diff lines
131 |     -- if cur on line of pos1, check if cursor column after pos1 column
132 |     return true 
133 |   elseif curpos[1]==pos2[1] and curpos[2] < pos2[2]  then
134 |     -- if cur on line of pos2 check if pos2 is after cursor
135 |     return true
136 |   elseif pos1[1]<curpos[1] and curpos[1]<pos2[1] then
137 |     --if curpos ,pos1 and pos2 on different lines, just check for lines
138 |     return true
139 |   end
140 |   return false
141 | end
142 | 
143 | function findenclosing_eq(curpos,positions)
144 |   --returns {pos1,pos2} if cursor is between some equation
145 |   --else returns nil
146 |   for i=1,counttable(positions),2 do
147 |     if inbetween(curpos,positions[i],positions[i+1]) then
148 |       return {positions[i],positions[i+1]}
149 |     end
150 |   end
151 |   return nil
152 | end
153 | 
154 | function RenderLatexAtCursor(opts)
155 |   RemoveLatex()
156 |   eqpos = find_equations()
157 |   curpos = vim.fn.getpos('.')
158 |   curpos = {curpos[2],curpos[3]}
159 |   cureqpos = findenclosing_eq(curpos,eqpos)
160 |   if cureqpos ~= nil then
161 |     lstrings = get_lstrings(cureqpos)
162 |     fnames = write_texfiles(lstrings)
163 |     latex_topng(fnames,opts.fargs[1])
164 |     insertpngs(cureqpos,fnames)
165 |   else
166 |     print("cursor not in equation")
167 |   end
168 | end
169 | 
170 | --function RenderLatex(opts)
171 | --  local timer = vim.loop.new_timer()
172 | --  timer:start(0,0,vim.schedule_wrap(renderlatex))
173 | --end
174 | 
175 | function RemoveLatex()
176 |   for k,img in pairs(imgs) do
177 |     img:delete(0,{free=true})
178 |   end
179 |   for k,v in pairs(imgs) do
180 |     imgs[k] = nil
181 |   end
182 | end
183 | 
184 | vim.api.nvim_create_user_command('RenderLatex', RenderLatex , {nargs=1, complete = function(ArgLead,CmdLine,CursorPos) 
185 | return {"200","300"} end })
186 | 
187 | vim.api.nvim_create_user_command('RenderLatexAtCursor', RenderLatexAtCursor , {nargs=1, complete = function(ArgLead,CmdLine,CursorPos) 
188 | return {"200","300"} end })
189 | 
190 | vim.api.nvim_create_user_command('RemoveLatex', RemoveLatex , {nargs=0})
191 | 


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