file.lua

   1 -- primitives for saving to file and loading from file
   2 function file_exists(filename)
   3   local infile = App.open_for_reading(filename)
   4   if infile then
   5     infile:close()
   6     return true
   7   else
   8     return false
   9   end
  10 end
  11
  12 function load_from_disk(State)
  13   local infile = App.open_for_reading(State.filename)
  14   State.lines = load_from_file(infile)
  15   if infile then infile:close() end
  16 end
  17
  18 function load_from_file(infile)
  19   local result = {}
  20   if infile then
  21     local infile_next_line = infile:lines()  -- works with both Lua files and LÖVE Files (https://www.love2d.org/wiki/File)
  22     while true do
  23       local line = infile_next_line()
  24       if line == nil then break end
  25       if line == '```lines' then  -- inflexible with whitespace since these files are always autogenerated
  26         table.insert(result, load_drawing(infile_next_line))
  27       else
  28         table.insert(result, {mode='text', data=line})
  29       end
  30     end
  31   end
  32   if #result == 0 then
  33     table.insert(result, {mode='text', data=''})
  34   end
  35   return result
  36 end
  37
  38 function save_to_disk(State)
  39   local outfile = App.open_for_writing(State.filename)
  40   if outfile == nil then
  41     error('failed to write to "'..State.filename..'"')
  42   end
  43   for _,line in ipairs(State.lines) do
  44     if line.mode == 'drawing' then
  45       store_drawing(outfile, line)
  46     else
  47       outfile:write(line.data, '\n')
  48     end
  49   end
  50   outfile:close()
  51 end
  52
  53 json = require 'json'
  54 function load_drawing(infile_next_line)
  55   local drawing = {mode='drawing', h=256/2, points={}, shapes={}, pending={}}
  56   while true do
  57     local line = infile_next_line()
  58     assert(line)
  59     if line == '```' then break end
  60     local shape = json.decode(line)
  61     if shape.mode == 'freehand' then
  62       -- no changes needed
  63     elseif shape.mode == 'line' or shape.mode == 'manhattan' then
  64       local name = shape.p1.name
  65       shape.p1 = Drawing.insert_point(drawing.points, shape.p1.x, shape.p1.y)
  66       drawing.points[shape.p1].name = name
  67       name = shape.p2.name
  68       shape.p2 = Drawing.insert_point(drawing.points, shape.p2.x, shape.p2.y)
  69       drawing.points[shape.p2].name = name
  70     elseif shape.mode == 'polygon' or shape.mode == 'rectangle' or shape.mode == 'square' then
  71       for i,p in ipairs(shape.vertices) do
  72         local name = p.name
  73         shape.vertices[i] = Drawing.insert_point(drawing.points, p.x,p.y)
  74         drawing.points[shape.vertices[i]].name = name
  75       end
  76     elseif shape.mode == 'circle' or shape.mode == 'arc' then
  77       local name = shape.center.name
  78       shape.center = Drawing.insert_point(drawing.points, shape.center.x,shape.center.y)
  79       drawing.points[shape.center].name = name
  80     elseif shape.mode == 'deleted' then
  81       -- ignore
  82     else
  83       print(shape.mode)
  84       assert(false)
  85     end
  86     table.insert(drawing.shapes, shape)
  87   end
  88   return drawing
  89 end
  90
  91 function store_drawing(outfile, drawing)
  92   outfile:write('```lines\n')
  93   for _,shape in ipairs(drawing.shapes) do
  94     if shape.mode == 'freehand' then
  95       outfile:write(json.encode(shape), '\n')
  96     elseif shape.mode == 'line' or shape.mode == 'manhattan' then
  97       local line = json.encode({mode=shape.mode, p1=drawing.points[shape.p1], p2=drawing.points[shape.p2]})
  98       outfile:write(line, '\n')
  99     elseif shape.mode == 'polygon' or shape.mode == 'rectangle' or shape.mode == 'square' then
 100       local obj = {mode=shape.mode, vertices={}}
 101       for _,p in ipairs(shape.vertices) do
 102         table.insert(obj.vertices, drawing.points[p])
 103       end
 104       local line = json.encode(obj)
 105       outfile:write(line, '\n')
 106     elseif shape.mode == 'circle' then
 107       outfile:write(json.encode({mode=shape.mode, center=drawing.points[shape.center], radius=shape.radius}), '\n')
 108     elseif shape.mode == 'arc' then
 109       outfile:write(json.encode({mode=shape.mode, center=drawing.points[shape.center], radius=shape.radius, start_angle=shape.start_angle, end_angle=shape.end_angle}), '\n')
 110     elseif shape.mode == 'deleted' then
 111       -- ignore
 112     else
 113       print(shape.mode)
 114       assert(false)
 115     end
 116   end
 117   outfile:write('```\n')
 118 end
 119
 120 -- for tests
 121 function load_array(a)
 122   local result = {}
 123   local next_line = ipairs(a)
 124   local i,line,drawing = 0, ''
 125   while true do
 126     i,line = next_line(a, i)
 127     if i == nil then break end
 128 --?     print(line)
 129     if line == '```lines' then  -- inflexible with whitespace since these files are always autogenerated
 130 --?       print('inserting drawing')
 131       i, drawing = load_drawing_from_array(next_line, a, i)
 132 --?       print('i now', i)
 133       table.insert(result, drawing)
 134     else
 135 --?       print('inserting text')
 136       table.insert(result, {mode='text', data=line})
 137     end
 138   end
 139   if #result == 0 then
 140     table.insert(result, {mode='text', data=''})
 141   end
 142   return result
 143 end
 144
 145 function load_drawing_from_array(iter, a, i)
 146   local drawing = {mode='drawing', h=256/2, points={}, shapes={}, pending={}}
 147   local line
 148   while true do
 149     i, line = iter(a, i)
 150     assert(i)
 151 --?     print(i)
 152     if line == '```' then break end
 153     local shape = json.decode(line)
 154     if shape.mode == 'freehand' then
 155       -- no changes needed
 156     elseif shape.mode == 'line' or shape.mode == 'manhattan' then
 157       local name = shape.p1.name
 158       shape.p1 = Drawing.insert_point(drawing.points, shape.p1.x, shape.p1.y)
 159       drawing.points[shape.p1].name = name
 160       name = shape.p2.name
 161       shape.p2 = Drawing.insert_point(drawing.points, shape.p2.x, shape.p2.y)
 162       drawing.points[shape.p2].name = name
 163     elseif shape.mode == 'polygon' or shape.mode == 'rectangle' or shape.mode == 'square' then
 164       for i,p in ipairs(shape.vertices) do
 165         local name = p.name
 166         shape.vertices[i] = Drawing.insert_point(drawing.points, p.x,p.y)
 167         drawing.points[shape.vertices[i]].name = name
 168       end
 169     elseif shape.mode == 'circle' or shape.mode == 'arc' then
 170       local name = shape.center.name
 171       shape.center = Drawing.insert_point(drawing.points, shape.center.x,shape.center.y)
 172       drawing.points[shape.center].name = name
 173     elseif shape.mode == 'deleted' then
 174       -- ignore
 175     else
 176       print(shape.mode)
 177       assert(false)
 178     end
 179     table.insert(drawing.shapes, shape)
 180   end
 181   return i, drawing
 182 end