undo creating new drawings

Dependencies

• [2] VJ77YABH more efficient undo/redo
• [3] U2TKUOID bugfix: undo drawing creation
• [4] UWNHC4AA redo y computations
• [5] DLQMM265 scroll past first page
• [6] SQLVYKVJ rename
• [*] 73OCE2MC after much struggle, a brute-force undo
• [*] OTIBCAUJ love2d scaffold

Change contents

• edit in undo.lua at line 45
  [2.218]

  [8.1147]
  + assert(#Lines > 0)

  + if s < 1 then s = 1 end

  + if s > #Lines then s = #Lines end

  + if e < 1 then e = 1 end

  + if e > #Lines then e = #Lines end
• replacement in main.lua at line 222
  [3.890]→[3.587:638](∅→∅)
  − Drawing.before = snapshot()
  [3.890]

  [3.890]
  + Drawing.before = snapshot(line_index-1, line_index)
• edit in main.lua at line 227
  [3.1148]

  [3.1148]
  + save_to_disk(Lines, Filename)

  + record_undo_event({before=Drawing.before, after=snapshot(line_index-1, line_index+1)})