select.lua

   1 -- helpers for selecting portions of text
   2
   3 -- Return any intersection of the region from State.selection1 to
   4 -- State.cursor1 (or current mouse, if mouse is pressed) with the region
   5 -- between {line=line_index, pos=apos} and {line=line_index, pos=bpos}.
   6 -- apos must be less than bpos. However State.selection1 and State.cursor1 can be in any order.
   7 -- Result: positions spos,epos between apos,bpos.
   8 function Text.clip_selection(State, line_index, apos, bpos)
   9   if State.selection1.line == nil then return nil,nil end
  10   -- min,max = sorted(State.selection1,State.cursor1)
  11   local minl,minp = State.selection1.line,State.selection1.pos
  12   local maxl,maxp
  13   if State.mouse_down then
  14     maxl,maxp = Text.mouse_pos(State)
  15   else
  16     maxl,maxp = State.cursor1.line,State.cursor1.pos
  17   end
  18   if Text.lt1({line=maxl, pos=maxp},
  19               {line=minl, pos=minp}) then
  20     minl,maxl = maxl,minl
  21     minp,maxp = maxp,minp
  22   end
  23   -- check if intervals are disjoint
  24   if line_index < minl then return nil,nil end
  25   if line_index > maxl then return nil,nil end
  26   if line_index == minl and bpos <= minp then return nil,nil end
  27   if line_index == maxl and apos >= maxp then return nil,nil end
  28   -- compare bounds more carefully (start inclusive, end exclusive)
  29   local a_ge = Text.le1({line=minl, pos=minp}, {line=line_index, pos=apos})
  30   local b_lt = Text.lt1({line=line_index, pos=bpos}, {line=maxl, pos=maxp})
  31   if a_ge and b_lt then
  32     -- fully contained
  33     return apos,bpos
  34   elseif a_ge then
  35     assert(maxl == line_index, ('maxl %d not equal to line_index %d'):format(maxl, line_index))
  36     return apos,maxp
  37   elseif b_lt then
  38     assert(minl == line_index, ('minl %d not equal to line_index %d'):format(minl, line_index))
  39     return minp,bpos
  40   else
  41     assert(minl == maxl and minl == line_index, ('minl %d, maxl %d and line_index %d are not all equal'):format(minl, maxl, line_index))
  42     return minp,maxp
  43   end
  44 end
  45
  46 -- draw highlight for line corresponding to (lo,hi) given an approximate x,y and pos on the same screen line
  47 -- Returns some intermediate computation useful elsewhere.
  48 function Text.draw_highlight(State, line, x,y, pos, lo,hi)
  49   if lo then
  50     local lo_offset = Text.offset(line.data, lo)
  51     local hi_offset = Text.offset(line.data, hi)
  52     local pos_offset = Text.offset(line.data, pos)
  53     local lo_px
  54     if pos == lo then
  55       lo_px = 0
  56     else
  57       local before = line.data:sub(pos_offset, lo_offset-1)
  58       lo_px = State.font:getWidth(before)
  59     end
  60     local s = line.data:sub(lo_offset, hi_offset-1)
  61     App.color(Highlight_color)
  62     love.graphics.rectangle('fill', x+lo_px,y, State.font:getWidth(s),State.line_height)
  63     App.color(Text_color)
  64     return lo_px
  65   end
  66 end
  67
  68 function Text.mouse_pos(State)
  69   local x,y = App.mouse_x(), App.mouse_y()
  70   if y < State.top then
  71     return State.screen_top1.line, State.screen_top1.pos
  72   end
  73   for line_index,line in ipairs(State.lines) do
  74     if Text.in_line(State, line_index, x,y) then
  75       return line_index, Text.to_pos_on_line(State, line_index, x,y)
  76     end
  77   end
  78   local screen_bottom1 = Text.screen_bottom1(State)
  79   return screen_bottom1.line, Text.pos_at_end_of_screen_line(State, screen_bottom1)
  80 end
  81
  82 function Text.cut_selection(State)
  83   if State.selection1.line == nil then return end
  84   local result = Text.selection(State)
  85   Text.delete_selection(State)
  86   return result
  87 end
  88
  89 function Text.delete_selection(State)
  90   if State.selection1.line == nil then return end
  91   local minl,maxl = minmax(State.selection1.line, State.cursor1.line)
  92   local before = snapshot(State, minl, maxl)
  93   Text.delete_selection_without_undo(State)
  94   record_undo_event(State, {before=before, after=snapshot(State, State.cursor1.line)})
  95 end
  96
  97 function Text.delete_selection_without_undo(State)
  98   if State.selection1.line == nil then return end
  99   -- min,max = sorted(State.selection1,State.cursor1)
 100   local minl,minp = State.selection1.line,State.selection1.pos
 101   local maxl,maxp = State.cursor1.line,State.cursor1.pos
 102   if minl > maxl then
 103     minl,maxl = maxl,minl
 104     minp,maxp = maxp,minp
 105   elseif minl == maxl then
 106     if minp > maxp then
 107       minp,maxp = maxp,minp
 108     end
 109   end
 110   -- update State.cursor1 and State.selection1
 111   State.cursor1.line = minl
 112   State.cursor1.pos = minp
 113   if Text.lt1(State.cursor1, State.screen_top1) then
 114     State.screen_top1.line = State.cursor1.line
 115     State.screen_top1.pos = Text.pos_at_start_of_screen_line(State, State.cursor1)
 116   end
 117   State.selection1 = {}
 118   -- delete everything between min (inclusive) and max (exclusive)
 119   Text.clear_screen_line_cache(State, minl)
 120   local min_offset = Text.offset(State.lines[minl].data, minp)
 121   local max_offset = Text.offset(State.lines[maxl].data, maxp)
 122   if minl == maxl then
 123 --?     print('minl == maxl')
 124     State.lines[minl].data = State.lines[minl].data:sub(1, min_offset-1)..State.lines[minl].data:sub(max_offset)
 125     return
 126   end
 127   assert(minl < maxl, ('minl %d not < maxl %d'):format(minl, maxl))
 128   local rhs = State.lines[maxl].data:sub(max_offset)
 129   for i=maxl,minl+1,-1 do
 130     table.remove(State.lines, i)
 131     table.remove(State.line_cache, i)
 132   end
 133   State.lines[minl].data = State.lines[minl].data:sub(1, min_offset-1)..rhs
 134 end
 135
 136 function Text.selection(State)
 137   if State.selection1.line == nil then return end
 138   -- min,max = sorted(State.selection1,State.cursor1)
 139   local minl,minp = State.selection1.line,State.selection1.pos
 140   local maxl,maxp = State.cursor1.line,State.cursor1.pos
 141   if minl > maxl then
 142     minl,maxl = maxl,minl
 143     minp,maxp = maxp,minp
 144   elseif minl == maxl then
 145     if minp > maxp then
 146       minp,maxp = maxp,minp
 147     end
 148   end
 149   local min_offset = Text.offset(State.lines[minl].data, minp)
 150   local max_offset = Text.offset(State.lines[maxl].data, maxp)
 151   if minl == maxl then
 152     return State.lines[minl].data:sub(min_offset, max_offset-1)
 153   end
 154   assert(minl < maxl, ('minl %d not < maxl %d'):format(minl, maxl))
 155   local result = {State.lines[minl].data:sub(min_offset)}
 156   for i=minl+1,maxl-1 do
 157     table.insert(result, State.lines[i].data)
 158   end
 159   table.insert(result, State.lines[maxl].data:sub(1, max_offset-1))
 160   return table.concat(result, '\n')
 161 end