text.lua

   1 -- text editor, particularly text drawing, horizontal wrap, vertical scrolling
   2 Text = {}
   3
   4 -- draw a line starting from startpos to screen at y between State.left and State.right
   5 -- return y for the next line, and position of start of final screen line drawn
   6 function Text.draw(State, line_index, y, startpos)
   7 --?   print('text.draw', line_index, y)
   8   local line = State.lines[line_index]
   9   local line_cache = State.line_cache[line_index]
  10   line_cache.starty = y
  11   line_cache.startpos = startpos
  12   -- wrap long lines
  13   local final_screen_line_starting_pos = startpos  -- track value to return
  14   Text.populate_screen_line_starting_pos(State, line_index)
  15   assert(#line_cache.screen_line_starting_pos >= 1)
  16   for i=1,#line_cache.screen_line_starting_pos do
  17     local pos = line_cache.screen_line_starting_pos[i]
  18     if pos < startpos then
  19       -- render nothing
  20     else
  21       final_screen_line_starting_pos = pos
  22       local screen_line = Text.screen_line(line, line_cache, i)
  23 --?       print('text.draw:', screen_line, 'at', line_index,pos, 'after', x,y)
  24       local frag_len = utf8.len(screen_line)
  25       -- render fragment
  26       if State.selection1.line then
  27         local lo, hi = Text.clip_selection(State, line_index, pos, pos+frag_len)
  28         Text.draw_highlight(State, line, State.left,y, pos, lo,hi)
  29       end
  30       App.color(Text_color)
  31       App.screen.print(screen_line, State.left,y)
  32       -- render cursor if necessary
  33       if line_index == State.cursor1.line then
  34         if pos <= State.cursor1.pos and pos + frag_len >= State.cursor1.pos then
  35           if State.search_term then
  36             if State.lines[State.cursor1.line].data:sub(State.cursor1.pos, State.cursor1.pos+utf8.len(State.search_term)-1) == State.search_term then
  37               local lo_px = Text.draw_highlight(State, line, State.left,y, pos, State.cursor1.pos, State.cursor1.pos+utf8.len(State.search_term))
  38               App.color(Text_color)
  39               love.graphics.print(State.search_term, State.left+lo_px,y)
  40             end
  41           else
  42             Text.draw_cursor(State, State.left+Text.x(screen_line, State.cursor1.pos-pos+1), y)
  43           end
  44         end
  45       end
  46       y = y + State.line_height
  47       if y >= App.screen.height then
  48         break
  49       end
  50     end
  51   end
  52   return y, final_screen_line_starting_pos
  53 end
  54
  55 function Text.screen_line(line, line_cache, i)
  56   local pos = line_cache.screen_line_starting_pos[i]
  57   local offset = Text.offset(line.data, pos)
  58   if i >= #line_cache.screen_line_starting_pos then
  59     return line.data:sub(offset)
  60   end
  61   local endpos = line_cache.screen_line_starting_pos[i+1]-1
  62   local end_offset = Text.offset(line.data, endpos)
  63   return line.data:sub(offset, end_offset)
  64 end
  65
  66 function Text.draw_cursor(State, x, y)
  67   -- blink every 0.5s
  68   if math.floor(Cursor_time*2)%2 == 0 then
  69     App.color(Cursor_color)
  70     love.graphics.rectangle('fill', x,y, 3,State.line_height)
  71   end
  72   State.cursor_x = x
  73   State.cursor_y = y+State.line_height
  74 end
  75
  76 function Text.populate_screen_line_starting_pos(State, line_index)
  77   local line = State.lines[line_index]
  78   if line.mode ~= 'text' then return end
  79   local line_cache = State.line_cache[line_index]
  80   if line_cache.screen_line_starting_pos then
  81     return
  82   end
  83   line_cache.screen_line_starting_pos = {1}
  84   local x = 0
  85   local pos = 1
  86   -- try to wrap at word boundaries
  87   for frag in line.data:gmatch('%S*%s*') do
  88     local frag_width = App.width(frag)
  89 --?     print('-- frag:', frag, pos, x, frag_width, State.width)
  90     while x + frag_width > State.width do
  91 --?       print('frag:', frag, pos, x, frag_width, State.width)
  92       if x < 0.8 * State.width then
  93         -- long word; chop it at some letter
  94         -- We're not going to reimplement TeX here.
  95         local bpos = Text.nearest_pos_less_than(frag, State.width - x)
  96         -- everything works if bpos == 0, but is a little inefficient
  97         pos = pos + bpos
  98         local boffset = Text.offset(frag, bpos+1)  -- byte _after_ bpos
  99         frag = string.sub(frag, boffset)
 100 --?         if bpos > 0 then
 101 --?           print('after chop:', frag)
 102 --?         end
 103         frag_width = App.width(frag)
 104       end
 105 --?       print('screen line:', pos)
 106       table.insert(line_cache.screen_line_starting_pos, pos)
 107       x = 0  -- new screen line
 108     end
 109     x = x + frag_width
 110     pos = pos + utf8.len(frag)
 111   end
 112 end
 113
 114 function Text.text_input(State, t)
 115   if App.mouse_down(1) then return end
 116   if App.ctrl_down() or App.alt_down() or App.cmd_down() then return end
 117   local before = snapshot(State, State.cursor1.line)
 118 --?   print(State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos, State.screen_bottom1.line, State.screen_bottom1.pos)
 119   Text.insert_at_cursor(State, t)
 120   if State.cursor_y > App.screen.height - State.line_height then
 121     Text.populate_screen_line_starting_pos(State, State.cursor1.line)
 122     Text.snap_cursor_to_bottom_of_screen(State, State.left, State.right)
 123   end
 124   record_undo_event(State, {before=before, after=snapshot(State, State.cursor1.line)})
 125 end
 126
 127 function Text.insert_at_cursor(State, t)
 128   assert(State.lines[State.cursor1.line].mode == 'text')
 129   local byte_offset = Text.offset(State.lines[State.cursor1.line].data, State.cursor1.pos)
 130   State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_offset-1)..t..string.sub(State.lines[State.cursor1.line].data, byte_offset)
 131   Text.clear_screen_line_cache(State, State.cursor1.line)
 132   State.cursor1.pos = State.cursor1.pos+1
 133 end
 134
 135 -- Don't handle any keys here that would trigger text_input above.
 136 function Text.keychord_press(State, chord)
 137 --?   print('chord', chord, State.selection1.line, State.selection1.pos)
 138   --== shortcuts that mutate text
 139   if chord == 'return' then
 140     local before_line = State.cursor1.line
 141     local before = snapshot(State, before_line)
 142     Text.insert_return(State)
 143     State.selection1 = {}
 144     if State.cursor_y > App.screen.height - State.line_height then
 145       Text.snap_cursor_to_bottom_of_screen(State, State.left, State.right)
 146     end
 147     schedule_save(State)
 148     record_undo_event(State, {before=before, after=snapshot(State, before_line, State.cursor1.line)})
 149   elseif chord == 'tab' then
 150     local before = snapshot(State, State.cursor1.line)
 151 --?     print(State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos, State.screen_bottom1.line, State.screen_bottom1.pos)
 152     Text.insert_at_cursor(State, '\t')
 153     if State.cursor_y > App.screen.height - State.line_height then
 154       Text.populate_screen_line_starting_pos(State, State.cursor1.line)
 155       Text.snap_cursor_to_bottom_of_screen(State, State.left, State.right)
 156 --?       print('=>', State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos, State.screen_bottom1.line, State.screen_bottom1.pos)
 157     end
 158     schedule_save(State)
 159     record_undo_event(State, {before=before, after=snapshot(State, State.cursor1.line)})
 160   elseif chord == 'backspace' then
 161     if State.selection1.line then
 162       Text.delete_selection(State, State.left, State.right)
 163       schedule_save(State)
 164       return
 165     end
 166     local before
 167     if State.cursor1.pos > 1 then
 168       before = snapshot(State, State.cursor1.line)
 169       local byte_start = utf8.offset(State.lines[State.cursor1.line].data, State.cursor1.pos-1)
 170       local byte_end = utf8.offset(State.lines[State.cursor1.line].data, State.cursor1.pos)
 171       if byte_start then
 172         if byte_end then
 173           State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_start-1)..string.sub(State.lines[State.cursor1.line].data, byte_end)
 174         else
 175           State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_start-1)
 176         end
 177         State.cursor1.pos = State.cursor1.pos-1
 178       end
 179     elseif State.cursor1.line > 1 then
 180       before = snapshot(State, State.cursor1.line-1, State.cursor1.line)
 181       if State.lines[State.cursor1.line-1].mode == 'drawing' then
 182         table.remove(State.lines, State.cursor1.line-1)
 183         table.remove(State.line_cache, State.cursor1.line-1)
 184       else
 185         -- join lines
 186         State.cursor1.pos = utf8.len(State.lines[State.cursor1.line-1].data)+1
 187         State.lines[State.cursor1.line-1].data = State.lines[State.cursor1.line-1].data..State.lines[State.cursor1.line].data
 188         table.remove(State.lines, State.cursor1.line)
 189         table.remove(State.line_cache, State.cursor1.line)
 190       end
 191       State.cursor1.line = State.cursor1.line-1
 192     end
 193     if State.screen_top1.line > #State.lines then
 194       Text.populate_screen_line_starting_pos(State, #State.lines)
 195       local line_cache = State.line_cache[#State.line_cache]
 196       State.screen_top1 = {line=#State.lines, pos=line_cache.screen_line_starting_pos[#line_cache.screen_line_starting_pos]}
 197     elseif Text.lt1(State.cursor1, State.screen_top1) then
 198       State.screen_top1 = {
 199         line=State.cursor1.line,
 200         pos=Text.pos_at_start_of_screen_line(State, State.cursor1),
 201       }
 202       Text.redraw_all(State)  -- if we're scrolling, reclaim all fragments to avoid memory leaks
 203     end
 204     Text.clear_screen_line_cache(State, State.cursor1.line)
 205     assert(Text.le1(State.screen_top1, State.cursor1))
 206     schedule_save(State)
 207     record_undo_event(State, {before=before, after=snapshot(State, State.cursor1.line)})
 208   elseif chord == 'delete' then
 209     if State.selection1.line then
 210       Text.delete_selection(State, State.left, State.right)
 211       schedule_save(State)
 212       return
 213     end
 214     local before
 215     if State.cursor1.pos <= utf8.len(State.lines[State.cursor1.line].data) then
 216       before = snapshot(State, State.cursor1.line)
 217     else
 218       before = snapshot(State, State.cursor1.line, State.cursor1.line+1)
 219     end
 220     if State.cursor1.pos <= utf8.len(State.lines[State.cursor1.line].data) then
 221       local byte_start = utf8.offset(State.lines[State.cursor1.line].data, State.cursor1.pos)
 222       local byte_end = utf8.offset(State.lines[State.cursor1.line].data, State.cursor1.pos+1)
 223       if byte_start then
 224         if byte_end then
 225           State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_start-1)..string.sub(State.lines[State.cursor1.line].data, byte_end)
 226         else
 227           State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_start-1)
 228         end
 229         -- no change to State.cursor1.pos
 230       end
 231     elseif State.cursor1.line < #State.lines then
 232       if State.lines[State.cursor1.line+1].mode == 'text' then
 233         -- join lines
 234         State.lines[State.cursor1.line].data = State.lines[State.cursor1.line].data..State.lines[State.cursor1.line+1].data
 235       end
 236       table.remove(State.lines, State.cursor1.line+1)
 237       table.remove(State.line_cache, State.cursor1.line+1)
 238     end
 239     Text.clear_screen_line_cache(State, State.cursor1.line)
 240     schedule_save(State)
 241     record_undo_event(State, {before=before, after=snapshot(State, State.cursor1.line)})
 242   --== shortcuts that move the cursor
 243   elseif chord == 'left' then
 244     Text.left(State)
 245     State.selection1 = {}
 246   elseif chord == 'right' then
 247     Text.right(State)
 248     State.selection1 = {}
 249   elseif chord == 'S-left' then
 250     if State.selection1.line == nil then
 251       State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
 252     end
 253     Text.left(State)
 254   elseif chord == 'S-right' then
 255     if State.selection1.line == nil then
 256       State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
 257     end
 258     Text.right(State)
 259   -- C- hotkeys reserved for drawings, so we'll use M-
 260   elseif chord == 'M-left' then
 261     Text.word_left(State)
 262     State.selection1 = {}
 263   elseif chord == 'M-right' then
 264     Text.word_right(State)
 265     State.selection1 = {}
 266   elseif chord == 'M-S-left' then
 267     if State.selection1.line == nil then
 268       State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
 269     end
 270     Text.word_left(State)
 271   elseif chord == 'M-S-right' then
 272     if State.selection1.line == nil then
 273       State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
 274     end
 275     Text.word_right(State)
 276   elseif chord == 'home' then
 277     Text.start_of_line(State)
 278     State.selection1 = {}
 279   elseif chord == 'end' then
 280     Text.end_of_line(State)
 281     State.selection1 = {}
 282   elseif chord == 'S-home' then
 283     if State.selection1.line == nil then
 284       State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
 285     end
 286     Text.start_of_line(State)
 287   elseif chord == 'S-end' then
 288     if State.selection1.line == nil then
 289       State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
 290     end
 291     Text.end_of_line(State)
 292   elseif chord == 'up' then
 293     Text.up(State)
 294     State.selection1 = {}
 295   elseif chord == 'down' then
 296     Text.down(State)
 297     State.selection1 = {}
 298   elseif chord == 'S-up' then
 299     if State.selection1.line == nil then
 300       State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
 301     end
 302     Text.up(State)
 303   elseif chord == 'S-down' then
 304     if State.selection1.line == nil then
 305       State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
 306     end
 307     Text.down(State)
 308   elseif chord == 'pageup' then
 309     Text.pageup(State)
 310     State.selection1 = {}
 311   elseif chord == 'pagedown' then
 312     Text.pagedown(State)
 313     State.selection1 = {}
 314   elseif chord == 'S-pageup' then
 315     if State.selection1.line == nil then
 316       State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
 317     end
 318     Text.pageup(State)
 319   elseif chord == 'S-pagedown' then
 320     if State.selection1.line == nil then
 321       State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
 322     end
 323     Text.pagedown(State)
 324   end
 325 end
 326
 327 function Text.insert_return(State)
 328   local byte_offset = Text.offset(State.lines[State.cursor1.line].data, State.cursor1.pos)
 329   table.insert(State.lines, State.cursor1.line+1, {mode='text', data=string.sub(State.lines[State.cursor1.line].data, byte_offset)})
 330   table.insert(State.line_cache, State.cursor1.line+1, {})
 331   State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_offset-1)
 332   Text.clear_screen_line_cache(State, State.cursor1.line)
 333   State.cursor1 = {line=State.cursor1.line+1, pos=1}
 334 end
 335
 336 function Text.pageup(State)
 337 --?   print('pageup')
 338   -- duplicate some logic from love.draw
 339   local top2 = Text.to2(State, State.screen_top1)
 340 --?   print(App.screen.height)
 341   local y = App.screen.height - State.line_height
 342   while y >= State.top do
 343 --?     print(y, top2.line, top2.screen_line, top2.screen_pos)
 344     if State.screen_top1.line == 1 and State.screen_top1.pos == 1 then break end
 345     if State.lines[State.screen_top1.line].mode == 'text' then
 346       y = y - State.line_height
 347     elseif State.lines[State.screen_top1.line].mode == 'drawing' then
 348       y = y - Drawing_padding_height - Drawing.pixels(State.lines[State.screen_top1.line].h, State.width)
 349     end
 350     top2 = Text.previous_screen_line(State, top2)
 351   end
 352   State.screen_top1 = Text.to1(State, top2)
 353   State.cursor1 = {line=State.screen_top1.line, pos=State.screen_top1.pos}
 354   Text.move_cursor_down_to_next_text_line_while_scrolling_again_if_necessary(State)
 355 --?   print(State.cursor1.line, State.cursor1.pos, State.screen_top1.line, State.screen_top1.pos)
 356 --?   print('pageup end')
 357 end
 358
 359 function Text.pagedown(State)
 360 --?   print('pagedown')
 361   -- If a line/paragraph gets to a page boundary, I often want to scroll
 362   -- before I get to the bottom.
 363   -- However, only do this if it makes forward progress.
 364   local bot2 = Text.to2(State, State.screen_bottom1)
 365   if bot2.screen_line > 1 then
 366     bot2.screen_line = math.max(bot2.screen_line-10, 1)
 367   end
 368   local new_top1 = Text.to1(State, bot2)
 369   if Text.lt1(State.screen_top1, new_top1) then
 370     State.screen_top1 = new_top1
 371   else
 372     State.screen_top1 = {line=State.screen_bottom1.line, pos=State.screen_bottom1.pos}
 373   end
 374 --?   print('setting top to', State.screen_top1.line, State.screen_top1.pos)
 375   State.cursor1 = {line=State.screen_top1.line, pos=State.screen_top1.pos}
 376   Text.move_cursor_down_to_next_text_line_while_scrolling_again_if_necessary(State)
 377 --?   print('top now', State.screen_top1.line)
 378   Text.redraw_all(State)  -- if we're scrolling, reclaim all fragments to avoid memory leaks
 379 --?   print('pagedown end')
 380 end
 381
 382 function Text.up(State)
 383   assert(State.lines[State.cursor1.line].mode == 'text')
 384 --?   print('up', State.cursor1.line, State.cursor1.pos, State.screen_top1.line, State.screen_top1.pos)
 385   local screen_line_starting_pos, screen_line_index = Text.pos_at_start_of_screen_line(State, State.cursor1)
 386   if screen_line_starting_pos == 1 then
 387 --?     print('cursor is at first screen line of its line')
 388     -- line is done; skip to previous text line
 389     local new_cursor_line = State.cursor1.line
 390     while new_cursor_line > 1 do
 391       new_cursor_line = new_cursor_line-1
 392       if State.lines[new_cursor_line].mode == 'text' then
 393 --?         print('found previous text line')
 394         State.cursor1 = {line=new_cursor_line, pos=nil}
 395         Text.populate_screen_line_starting_pos(State, State.cursor1.line)
 396         -- previous text line found, pick its final screen line
 397 --?         print('has multiple screen lines')
 398         local screen_line_starting_pos = State.line_cache[State.cursor1.line].screen_line_starting_pos
 399 --?         print(#screen_line_starting_pos)
 400         screen_line_starting_pos = screen_line_starting_pos[#screen_line_starting_pos]
 401         local screen_line_starting_byte_offset = Text.offset(State.lines[State.cursor1.line].data, screen_line_starting_pos)
 402         local s = string.sub(State.lines[State.cursor1.line].data, screen_line_starting_byte_offset)
 403         State.cursor1.pos = screen_line_starting_pos + Text.nearest_cursor_pos(s, State.cursor_x, State.left) - 1
 404         break
 405       end
 406     end
 407   else
 408     -- move up one screen line in current line
 409     assert(screen_line_index > 1)
 410     local new_screen_line_starting_pos = State.line_cache[State.cursor1.line].screen_line_starting_pos[screen_line_index-1]
 411     local new_screen_line_starting_byte_offset = Text.offset(State.lines[State.cursor1.line].data, new_screen_line_starting_pos)
 412     local s = string.sub(State.lines[State.cursor1.line].data, new_screen_line_starting_byte_offset)
 413     State.cursor1.pos = new_screen_line_starting_pos + Text.nearest_cursor_pos(s, State.cursor_x, State.left) - 1
 414 --?     print('cursor pos is now '..tostring(State.cursor1.pos))
 415   end
 416   if Text.lt1(State.cursor1, State.screen_top1) then
 417     State.screen_top1 = {
 418       line=State.cursor1.line,
 419       pos=Text.pos_at_start_of_screen_line(State, State.cursor1),
 420     }
 421     Text.redraw_all(State)  -- if we're scrolling, reclaim all fragments to avoid memory leaks
 422   end
 423 end
 424
 425 function Text.down(State)
 426   assert(State.lines[State.cursor1.line].mode == 'text')
 427 --?   print('down', State.cursor1.line, State.cursor1.pos, State.screen_top1.line, State.screen_top1.pos, State.screen_bottom1.line, State.screen_bottom1.pos)
 428   if Text.cursor_at_final_screen_line(State) then
 429     -- line is done, skip to next text line
 430 --?     print('cursor at final screen line of its line')
 431     local new_cursor_line = State.cursor1.line
 432     while new_cursor_line < #State.lines do
 433       new_cursor_line = new_cursor_line+1
 434       if State.lines[new_cursor_line].mode == 'text' then
 435         State.cursor1 = {
 436           line = new_cursor_line,
 437           pos = Text.nearest_cursor_pos(State.lines[new_cursor_line].data, State.cursor_x, State.left),
 438         }
 439 --?         print(State.cursor1.pos)
 440         break
 441       end
 442     end
 443     if State.cursor1.line > State.screen_bottom1.line then
 444 --?       print('screen top before:', State.screen_top1.line, State.screen_top1.pos)
 445 --?       print('scroll up preserving cursor')
 446       Text.snap_cursor_to_bottom_of_screen(State)
 447 --?       print('screen top after:', State.screen_top1.line, State.screen_top1.pos)
 448     end
 449   else
 450     -- move down one screen line in current line
 451     local scroll_down = Text.le1(State.screen_bottom1, State.cursor1)
 452 --?     print('cursor is NOT at final screen line of its line')
 453     local screen_line_starting_pos, screen_line_index = Text.pos_at_start_of_screen_line(State, State.cursor1)
 454     Text.populate_screen_line_starting_pos(State, State.cursor1.line)
 455     local new_screen_line_starting_pos = State.line_cache[State.cursor1.line].screen_line_starting_pos[screen_line_index+1]
 456 --?     print('switching pos of screen line at cursor from '..tostring(screen_line_starting_pos)..' to '..tostring(new_screen_line_starting_pos))
 457     local new_screen_line_starting_byte_offset = Text.offset(State.lines[State.cursor1.line].data, new_screen_line_starting_pos)
 458     local s = string.sub(State.lines[State.cursor1.line].data, new_screen_line_starting_byte_offset)
 459     State.cursor1.pos = new_screen_line_starting_pos + Text.nearest_cursor_pos(s, State.cursor_x, State.left) - 1
 460 --?     print('cursor pos is now', State.cursor1.line, State.cursor1.pos)
 461     if scroll_down then
 462 --?       print('scroll up preserving cursor')
 463       Text.snap_cursor_to_bottom_of_screen(State)
 464 --?       print('screen top after:', State.screen_top1.line, State.screen_top1.pos)
 465     end
 466   end
 467 --?   print('=>', State.cursor1.line, State.cursor1.pos, State.screen_top1.line, State.screen_top1.pos, State.screen_bottom1.line, State.screen_bottom1.pos)
 468 end
 469
 470 function Text.start_of_line(State)
 471   State.cursor1.pos = 1
 472   if Text.lt1(State.cursor1, State.screen_top1) then
 473     State.screen_top1 = {line=State.cursor1.line, pos=State.cursor1.pos}  -- copy
 474   end
 475 end
 476
 477 function Text.end_of_line(State)
 478   State.cursor1.pos = utf8.len(State.lines[State.cursor1.line].data) + 1
 479   if Text.cursor_out_of_screen(State) then
 480     Text.snap_cursor_to_bottom_of_screen(State)
 481   end
 482 end
 483
 484 function Text.word_left(State)
 485   -- skip some whitespace
 486   while true do
 487     if State.cursor1.pos == 1 then
 488       break
 489     end
 490     if Text.match(State.lines[State.cursor1.line].data, State.cursor1.pos-1, '%S') then
 491       break
 492     end
 493     Text.left(State)
 494   end
 495   -- skip some non-whitespace
 496   while true do
 497     Text.left(State)
 498     if State.cursor1.pos == 1 then
 499       break
 500     end
 501     assert(State.cursor1.pos > 1)
 502     if Text.match(State.lines[State.cursor1.line].data, State.cursor1.pos-1, '%s') then
 503       break
 504     end
 505   end
 506 end
 507
 508 function Text.word_right(State)
 509   -- skip some whitespace
 510   while true do
 511     if State.cursor1.pos > utf8.len(State.lines[State.cursor1.line].data) then
 512       break
 513     end
 514     if Text.match(State.lines[State.cursor1.line].data, State.cursor1.pos, '%S') then
 515       break
 516     end
 517     Text.right_without_scroll(State)
 518   end
 519   while true do
 520     Text.right_without_scroll(State)
 521     if State.cursor1.pos > utf8.len(State.lines[State.cursor1.line].data) then
 522       break
 523     end
 524     if Text.match(State.lines[State.cursor1.line].data, State.cursor1.pos, '%s') then
 525       break
 526     end
 527   end
 528   if Text.cursor_out_of_screen(State) then
 529     Text.snap_cursor_to_bottom_of_screen(State)
 530   end
 531 end
 532
 533 function Text.match(s, pos, pat)
 534   local start_offset = Text.offset(s, pos)
 535   assert(start_offset)
 536   local end_offset = Text.offset(s, pos+1)
 537   assert(end_offset > start_offset)
 538   local curr = s:sub(start_offset, end_offset-1)
 539   return curr:match(pat)
 540 end
 541
 542 function Text.left(State)
 543   assert(State.lines[State.cursor1.line].mode == 'text')
 544   if State.cursor1.pos > 1 then
 545     State.cursor1.pos = State.cursor1.pos-1
 546   else
 547     local new_cursor_line = State.cursor1.line
 548     while new_cursor_line > 1 do
 549       new_cursor_line = new_cursor_line-1
 550       if State.lines[new_cursor_line].mode == 'text' then
 551         State.cursor1 = {
 552           line = new_cursor_line,
 553           pos = utf8.len(State.lines[new_cursor_line].data) + 1,
 554         }
 555         break
 556       end
 557     end
 558   end
 559   if Text.lt1(State.cursor1, State.screen_top1) then
 560     State.screen_top1 = {
 561       line=State.cursor1.line,
 562       pos=Text.pos_at_start_of_screen_line(State, State.cursor1),
 563     }
 564     Text.redraw_all(State)  -- if we're scrolling, reclaim all fragments to avoid memory leaks
 565   end
 566 end
 567
 568 function Text.right(State)
 569   Text.right_without_scroll(State)
 570   if Text.cursor_out_of_screen(State) then
 571     Text.snap_cursor_to_bottom_of_screen(State)
 572   end
 573 end
 574
 575 function Text.right_without_scroll(State)
 576   assert(State.lines[State.cursor1.line].mode == 'text')
 577   if State.cursor1.pos <= utf8.len(State.lines[State.cursor1.line].data) then
 578     State.cursor1.pos = State.cursor1.pos+1
 579   else
 580     local new_cursor_line = State.cursor1.line
 581     while new_cursor_line <= #State.lines-1 do
 582       new_cursor_line = new_cursor_line+1
 583       if State.lines[new_cursor_line].mode == 'text' then
 584         State.cursor1 = {line=new_cursor_line, pos=1}
 585         break
 586       end
 587     end
 588   end
 589 end
 590
 591 function Text.pos_at_start_of_screen_line(State, loc1)
 592   Text.populate_screen_line_starting_pos(State, loc1.line)
 593   local line_cache = State.line_cache[loc1.line]
 594   for i=#line_cache.screen_line_starting_pos,1,-1 do
 595     local spos = line_cache.screen_line_starting_pos[i]
 596     if spos <= loc1.pos then
 597       return spos,i
 598     end
 599   end
 600   assert(false)
 601 end
 602
 603 function Text.cursor_at_final_screen_line(State)
 604   Text.populate_screen_line_starting_pos(State, State.cursor1.line)
 605   local screen_lines = State.line_cache[State.cursor1.line].screen_line_starting_pos
 606 --?   print(screen_lines[#screen_lines], State.cursor1.pos)
 607   return screen_lines[#screen_lines] <= State.cursor1.pos
 608 end
 609
 610 function Text.move_cursor_down_to_next_text_line_while_scrolling_again_if_necessary(State)
 611   local y = State.top
 612   while State.cursor1.line <= #State.lines do
 613     if State.lines[State.cursor1.line].mode == 'text' then
 614       break
 615     end
 616 --?     print('cursor skips', State.cursor1.line)
 617     y = y + Drawing_padding_height + Drawing.pixels(State.lines[State.cursor1.line].h, State.width)
 618     State.cursor1.line = State.cursor1.line + 1
 619   end
 620   -- hack: insert a text line at bottom of file if necessary
 621   if State.cursor1.line > #State.lines then
 622     assert(State.cursor1.line == #State.lines+1)
 623     table.insert(State.lines, {mode='text', data=''})
 624     table.insert(State.line_cache, {})
 625   end
 626 --?   print(y, App.screen.height, App.screen.height-State.line_height)
 627   if y > App.screen.height - State.line_height then
 628 --?     print('scroll up')
 629     Text.snap_cursor_to_bottom_of_screen(State)
 630   end
 631 end
 632
 633 -- should never modify State.cursor1
 634 function Text.snap_cursor_to_bottom_of_screen(State)
 635 --?   print('to2:', State.cursor1.line, State.cursor1.pos)
 636   local top2 = Text.to2(State, State.cursor1)
 637 --?   print('to2: =>', top2.line, top2.screen_line, top2.screen_pos)
 638   -- slide to start of screen line
 639   top2.screen_pos = 1  -- start of screen line
 640 --?   print('snap', State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos, State.screen_bottom1.line, State.screen_bottom1.pos)
 641 --?   print('cursor pos '..tostring(State.cursor1.pos)..' is on the #'..tostring(top2.screen_line)..' screen line down')
 642   local y = App.screen.height - State.line_height
 643   -- duplicate some logic from love.draw
 644   while true do
 645 --?     print(y, 'top2:', top2.line, top2.screen_line, top2.screen_pos)
 646     if top2.line == 1 and top2.screen_line == 1 then break end
 647     if top2.screen_line > 1 or State.lines[top2.line-1].mode == 'text' then
 648       local h = State.line_height
 649       if y - h < State.top then
 650         break
 651       end
 652       y = y - h
 653     else
 654       assert(top2.line > 1)
 655       assert(State.lines[top2.line-1].mode == 'drawing')
 656       -- We currently can't draw partial drawings, so either skip it entirely
 657       -- or not at all.
 658       local h = Drawing_padding_height + Drawing.pixels(State.lines[top2.line-1].h, State.width)
 659       if y - h < State.top then
 660         break
 661       end
 662 --?       print('skipping drawing of height', h)
 663       y = y - h
 664     end
 665     top2 = Text.previous_screen_line(State, top2)
 666   end
 667 --?   print('top2 finally:', top2.line, top2.screen_line, top2.screen_pos)
 668   State.screen_top1 = Text.to1(State, top2)
 669 --?   print('top1 finally:', State.screen_top1.line, State.screen_top1.pos)
 670 --?   print('snap =>', State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos, State.screen_bottom1.line, State.screen_bottom1.pos)
 671   Text.redraw_all(State)  -- if we're scrolling, reclaim all fragments to avoid memory leaks
 672 end
 673
 674 function Text.in_line(State, line_index, x,y)
 675   local line = State.lines[line_index]
 676   local line_cache = State.line_cache[line_index]
 677   if line_cache.starty == nil then return false end  -- outside current page
 678   if y < line_cache.starty then return false end
 679   Text.populate_screen_line_starting_pos(State, line_index)
 680   return y < line_cache.starty + State.line_height*(#line_cache.screen_line_starting_pos - Text.screen_line_index(line_cache.screen_line_starting_pos, line_cache.startpos) + 1)
 681 end
 682
 683 -- convert mx,my in pixels to schema-1 coordinates
 684 function Text.to_pos_on_line(State, line_index, mx, my)
 685   local line = State.lines[line_index]
 686   local line_cache = State.line_cache[line_index]
 687   assert(my >= line_cache.starty)
 688   -- duplicate some logic from Text.draw
 689   local y = line_cache.starty
 690   local start_screen_line_index = Text.screen_line_index(line_cache.screen_line_starting_pos, line_cache.startpos)
 691   for screen_line_index = start_screen_line_index,#line_cache.screen_line_starting_pos do
 692     local screen_line_starting_pos = line_cache.screen_line_starting_pos[screen_line_index]
 693     local screen_line_starting_byte_offset = Text.offset(line.data, screen_line_starting_pos)
 694 --?     print('iter', y, screen_line_index, screen_line_starting_pos, string.sub(line.data, screen_line_starting_byte_offset))
 695     local nexty = y + State.line_height
 696     if my < nexty then
 697       -- On all wrapped screen lines but the final one, clicks past end of
 698       -- line position cursor on final character of screen line.
 699       -- (The final screen line positions past end of screen line as always.)
 700       if screen_line_index < #line_cache.screen_line_starting_pos and mx > State.left + Text.screen_line_width(State, line_index, screen_line_index) then
 701 --?         print('past end of non-final line; return')
 702         return line_cache.screen_line_starting_pos[screen_line_index+1]-1
 703       end
 704       local s = string.sub(line.data, screen_line_starting_byte_offset)
 705 --?       print('return', mx, Text.nearest_cursor_pos(s, mx, State.left), '=>', screen_line_starting_pos + Text.nearest_cursor_pos(s, mx, State.left) - 1)
 706       return screen_line_starting_pos + Text.nearest_cursor_pos(s, mx, State.left) - 1
 707     end
 708     y = nexty
 709   end
 710   assert(false)
 711 end
 712
 713 function Text.screen_line_width(State, line_index, i)
 714   local line = State.lines[line_index]
 715   local line_cache = State.line_cache[line_index]
 716   local start_pos = line_cache.screen_line_starting_pos[i]
 717   local start_offset = Text.offset(line.data, start_pos)
 718   local screen_line
 719   if i < #line_cache.screen_line_starting_pos then
 720     local past_end_pos = line_cache.screen_line_starting_pos[i+1]
 721     local past_end_offset = Text.offset(line.data, past_end_pos)
 722     screen_line = string.sub(line.data, start_offset, past_end_offset-1)
 723   else
 724     screen_line = string.sub(line.data, start_pos)
 725   end
 726   return App.width(screen_line)
 727 end
 728
 729 function Text.screen_line_index(screen_line_starting_pos, pos)
 730   for i = #screen_line_starting_pos,1,-1 do
 731     if screen_line_starting_pos[i] <= pos then
 732       return i
 733     end
 734   end
 735 end
 736
 737 -- convert x pixel coordinate to pos
 738 -- oblivious to wrapping
 739 -- result: 1 to len+1
 740 function Text.nearest_cursor_pos(line, x, left)
 741   if x < left then
 742     return 1
 743   end
 744   local len = utf8.len(line)
 745   local max_x = left+Text.x(line, len+1)
 746   if x > max_x then
 747     return len+1
 748   end
 749   local leftpos, rightpos = 1, len+1
 750 --?   print('-- nearest', x)
 751   while true do
 752 --?     print('nearest', x, '^'..line..'$', leftpos, rightpos)
 753     if leftpos == rightpos then
 754       return leftpos
 755     end
 756     local curr = math.floor((leftpos+rightpos)/2)
 757     local currxmin = left+Text.x(line, curr)
 758     local currxmax = left+Text.x(line, curr+1)
 759 --?     print('nearest', x, leftpos, rightpos, curr, currxmin, currxmax)
 760     if currxmin <= x and x < currxmax then
 761       if x-currxmin < currxmax-x then
 762         return curr
 763       else
 764         return curr+1
 765       end
 766     end
 767     if leftpos >= rightpos-1 then
 768       return rightpos
 769     end
 770     if currxmin > x then
 771       rightpos = curr
 772     else
 773       leftpos = curr
 774     end
 775   end
 776   assert(false)
 777 end
 778
 779 -- return the nearest index of line (in utf8 code points) which lies entirely
 780 -- within x pixels of the left margin
 781 -- result: 0 to len+1
 782 function Text.nearest_pos_less_than(line, x)
 783 --?   print('', '-- nearest_pos_less_than', line, x)
 784   local len = utf8.len(line)
 785   local max_x = Text.x_after(line, len)
 786   if x > max_x then
 787     return len+1
 788   end
 789   local left, right = 0, len+1
 790   while true do
 791     local curr = math.floor((left+right)/2)
 792     local currxmin = Text.x_after(line, curr+1)
 793     local currxmax = Text.x_after(line, curr+2)
 794 --?     print('', x, left, right, curr, currxmin, currxmax)
 795     if currxmin <= x and x < currxmax then
 796       return curr
 797     end
 798     if left >= right-1 then
 799       return left
 800     end
 801     if currxmin > x then
 802       right = curr
 803     else
 804       left = curr
 805     end
 806   end
 807   assert(false)
 808 end
 809
 810 function Text.x_after(s, pos)
 811   local offset = Text.offset(s, math.min(pos+1, #s+1))
 812   local s_before = s:sub(1, offset-1)
 813 --?   print('^'..s_before..'$')
 814   return App.width(s_before)
 815 end
 816
 817 function Text.x(s, pos)
 818   local offset = Text.offset(s, pos)
 819   local s_before = s:sub(1, offset-1)
 820   return App.width(s_before)
 821 end
 822
 823 function Text.to2(State, loc1)
 824   if State.lines[loc1.line].mode == 'drawing' then
 825     return {line=loc1.line, screen_line=1, screen_pos=1}
 826   end
 827   local result = {line=loc1.line}
 828   local line_cache = State.line_cache[loc1.line]
 829   Text.populate_screen_line_starting_pos(State, loc1.line)
 830   for i=#line_cache.screen_line_starting_pos,1,-1 do
 831     local spos = line_cache.screen_line_starting_pos[i]
 832     if spos <= loc1.pos then
 833       result.screen_line = i
 834       result.screen_pos = loc1.pos - spos + 1
 835       break
 836     end
 837   end
 838   assert(result.screen_pos)
 839   return result
 840 end
 841
 842 function Text.to1(State, loc2)
 843   local result = {line=loc2.line, pos=loc2.screen_pos}
 844   if loc2.screen_line > 1 then
 845     result.pos = State.line_cache[loc2.line].screen_line_starting_pos[loc2.screen_line] + loc2.screen_pos - 1
 846   end
 847   return result
 848 end
 849
 850 function Text.eq1(a, b)
 851   return a.line == b.line and a.pos == b.pos
 852 end
 853
 854 function Text.lt1(a, b)
 855   if a.line < b.line then
 856     return true
 857   end
 858   if a.line > b.line then
 859     return false
 860   end
 861   return a.pos < b.pos
 862 end
 863
 864 function Text.le1(a, b)
 865   if a.line < b.line then
 866     return true
 867   end
 868   if a.line > b.line then
 869     return false
 870   end
 871   return a.pos <= b.pos
 872 end
 873
 874 function Text.offset(s, pos1)
 875   if pos1 == 1 then return 1 end
 876   local result = utf8.offset(s, pos1)
 877   if result == nil then
 878     print(pos1, #s, s)
 879   end
 880   assert(result)
 881   return result
 882 end
 883
 884 function Text.previous_screen_line(State, loc2)
 885   if loc2.screen_line > 1 then
 886     return {line=loc2.line, screen_line=loc2.screen_line-1, screen_pos=1}
 887   elseif loc2.line == 1 then
 888     return loc2
 889   elseif State.lines[loc2.line-1].mode == 'drawing' then
 890     return {line=loc2.line-1, screen_line=1, screen_pos=1}
 891   else
 892     local l = State.lines[loc2.line-1]
 893     Text.populate_screen_line_starting_pos(State, loc2.line-1)
 894     return {line=loc2.line-1, screen_line=#State.line_cache[loc2.line-1].screen_line_starting_pos, screen_pos=1}
 895   end
 896 end
 897
 898 -- resize helper
 899 function Text.tweak_screen_top_and_cursor(State)
 900   if State.screen_top1.pos == 1 then return end
 901   Text.populate_screen_line_starting_pos(State, State.screen_top1.line)
 902   local line = State.lines[State.screen_top1.line]
 903   local line_cache = State.line_cache[State.screen_top1.line]
 904   for i=2,#line_cache.screen_line_starting_pos do
 905     local pos = line_cache.screen_line_starting_pos[i]
 906     if pos == State.screen_top1.pos then
 907       break
 908     end
 909     if pos > State.screen_top1.pos then
 910       -- make sure screen top is at start of a screen line
 911       local prev = line_cache.screen_line_starting_pos[i-1]
 912       if State.screen_top1.pos - prev < pos - State.screen_top1.pos then
 913         State.screen_top1.pos = prev
 914       else
 915         State.screen_top1.pos = pos
 916       end
 917       break
 918     end
 919   end
 920   -- make sure cursor is on screen
 921   if Text.lt1(State.cursor1, State.screen_top1) then
 922     State.cursor1 = {line=State.screen_top1.line, pos=State.screen_top1.pos}
 923   elseif State.cursor1.line >= State.screen_bottom1.line then
 924 --?     print('too low')
 925     if Text.cursor_out_of_screen(State) then
 926 --?       print('tweak')
 927       State.cursor1 = {
 928           line=State.screen_bottom1.line,
 929           pos=Text.to_pos_on_line(State, State.screen_bottom1.line, State.right-5, App.screen.height-5),
 930       }
 931     end
 932   end
 933 end
 934
 935 -- slightly expensive since it redraws the screen
 936 function Text.cursor_out_of_screen(State)
 937   edit.draw(State)
 938   return State.cursor_y == nil
 939   -- this approach is cheaper and almost works, except on the final screen
 940   -- where file ends above bottom of screen
 941 --?   local botpos = Text.pos_at_start_of_screen_line(State, State.cursor1)
 942 --?   local botline1 = {line=State.cursor1.line, pos=botpos}
 943 --?   return Text.lt1(State.screen_bottom1, botline1)
 944 end
 945
 946 function Text.redraw_all(State)
 947 --?   print('clearing fragments')
 948   State.line_cache = {}
 949   for i=1,#State.lines do
 950     State.line_cache[i] = {}
 951   end
 952 end
 953
 954 function Text.clear_screen_line_cache(State, line_index)
 955   State.line_cache[line_index].screen_line_starting_pos = nil
 956 end
 957
 958 function trim(s)
 959   return s:gsub('^%s+', ''):gsub('%s+$', '')
 960 end
 961
 962 function ltrim(s)
 963   return s:gsub('^%s+', '')
 964 end
 965
 966 function rtrim(s)
 967   return s:gsub('%s+$', '')
 968 end
 969
 970 function starts_with(s, prefix)
 971   if #s < #prefix then
 972     return false
 973   end
 974   for i=1,#prefix do
 975     if s:sub(i,i) ~= prefix:sub(i,i) then
 976       return false
 977     end
 978   end
 979   return true
 980 end
 981
 982 function ends_with(s, suffix)
 983   if #s < #suffix then
 984     return false
 985   end
 986   for i=0,#suffix-1 do
 987     if s:sub(#s-i,#s-i) ~= suffix:sub(#suffix-i,#suffix-i) then
 988       return false
 989     end
 990   end
 991   return true
 992 end