1 files changed, 183 insertions, 0 deletions
diff --git a/source_select.lua b/source_select.lua
new file mode 100644
index 0000000..297a7bc
--- /dev/null
+++ b/source_select.lua
@@ -0,0 +1,183 @@
+-- helpers for selecting portions of text
+-- To keep things simple, we'll ignore the B side when selections start on the
+-- A side, and stick to within a single B side selections start in.
+
+-- Return any intersection of the region from State.selection1 to State.cursor1 (or
+-- current mouse, if mouse is pressed; or recent mouse if mouse is pressed and
+-- currently over a drawing) with the region between {line=line_index, pos=apos}
+-- and {line=line_index, pos=bpos}.
+-- apos must be less than bpos. However State.selection1 and State.cursor1 can be in any order.
+-- Result: positions spos,epos between apos,bpos.
+function Text.clip_selection(State, line_index, apos, bpos)
+  if State.selection1.line == nil then return nil,nil end
+  -- min,max = sorted(State.selection1,State.cursor1)
+  local minl,minp = State.selection1.line,State.selection1.pos
+  local maxl,maxp
+  if App.mouse_down(1) then
+    maxl,maxp = Text.mouse_pos(State)
+  else
+    maxl,maxp = State.cursor1.line,State.cursor1.pos
+  end
+  if Text.lt1({line=maxl, pos=maxp},
+              {line=minl, pos=minp}) then
+    minl,maxl = maxl,minl
+    minp,maxp = maxp,minp
+  end
+  -- check if intervals are disjoint
+  if line_index < minl then return nil,nil end
+  if line_index > maxl then return nil,nil end
+  if line_index == minl and bpos <= minp then return nil,nil end
+  if line_index == maxl and apos >= maxp then return nil,nil end
+  -- compare bounds more carefully (start inclusive, end exclusive)
+  local a_ge = Text.le1({line=minl, pos=minp}, {line=line_index, pos=apos})
+  local b_lt = Text.lt1({line=line_index, pos=bpos}, {line=maxl, pos=maxp})
+--?   print(minl,line_index,maxl, '--', minp,apos,bpos,maxp, '--', a_ge,b_lt)
+  if a_ge and b_lt then
+    -- fully contained
+    return apos,bpos
+  elseif a_ge then
+    assert(maxl == line_index)
+    return apos,maxp
+  elseif b_lt then
+    assert(minl == line_index)
+    return minp,bpos
+  else
+    assert(minl == maxl and minl == line_index)
+    return minp,maxp
+  end
+end
+
+-- draw highlight for line corresponding to (lo,hi) given an approximate x,y and pos on the same screen line
+-- Creates text objects every time, so use this sparingly.
+-- Returns some intermediate computation useful elsewhere.
+function Text.draw_highlight(State, line, x,y, pos, lo,hi)
+  if lo then
+    local lo_offset = Text.offset(line.data, lo)
+    local hi_offset = Text.offset(line.data, hi)
+    local pos_offset = Text.offset(line.data, pos)
+    local lo_px
+    if pos == lo then
+      lo_px = 0
+    else
+      local before = line.data:sub(pos_offset, lo_offset-1)
+      local before_text = App.newText(love.graphics.getFont(), before)
+      lo_px = App.width(before_text)
+    end
+--?     print(lo,pos,hi, '--', lo_offset,pos_offset,hi_offset, '--', lo_px)
+    local s = line.data:sub(lo_offset, hi_offset-1)
+    local text = App.newText(love.graphics.getFont(), s)
+    local text_width = App.width(text)
+    App.color(Highlight_color)
+    love.graphics.rectangle('fill', x+lo_px,y, text_width,State.line_height)
+    App.color(Text_color)
+    return lo_px
+  end
+end
+
+-- inefficient for some reason, so don't do it on every frame
+function Text.mouse_pos(State)
+  local time = love.timer.getTime()
+  if State.recent_mouse.time and State.recent_mouse.time > time-0.1 then
+    return State.recent_mouse.line, State.recent_mouse.pos
+  end
+  State.recent_mouse.time = time
+  local line,pos = Text.to_pos(State, App.mouse_x(), App.mouse_y())
+  if line then
+    State.recent_mouse.line = line
+    State.recent_mouse.pos = pos
+  end
+  return State.recent_mouse.line, State.recent_mouse.pos
+end
+
+function Text.to_pos(State, x,y)
+  for line_index,line in ipairs(State.lines) do
+    if line.mode == 'text' then
+      if Text.in_line(State, line_index, x,y) then
+        return line_index, Text.to_pos_on_line(State, line_index, x,y)
+      end
+    end
+  end
+end
+
+function Text.cut_selection(State)
+  if State.selection1.line == nil then return end
+  local result = Text.selection(State)
+  Text.delete_selection(State)
+  return result
+end
+
+function Text.delete_selection(State)
+  if State.selection1.line == nil then return end
+  local minl,maxl = minmax(State.selection1.line, State.cursor1.line)
+  local before = snapshot(State, minl, maxl)
+  Text.delete_selection_without_undo(State)
+  record_undo_event(State, {before=before, after=snapshot(State, State.cursor1.line)})
+end
+
+function Text.delete_selection_without_undo(State)
+  if State.selection1.line == nil then return end
+  -- min,max = sorted(State.selection1,State.cursor1)
+  local minl,minp = State.selection1.line,State.selection1.pos
+  local maxl,maxp = State.cursor1.line,State.cursor1.pos
+  if minl > maxl then
+    minl,maxl = maxl,minl
+    minp,maxp = maxp,minp
+  elseif minl == maxl then
+    if minp > maxp then
+      minp,maxp = maxp,minp
+    end
+  end
+  -- update State.cursor1 and State.selection1
+  State.cursor1.line = minl
+  State.cursor1.pos = minp
+  if Text.lt1(State.cursor1, State.screen_top1) then
+    State.screen_top1.line = State.cursor1.line
+    State.screen_top1.pos = Text.pos_at_start_of_screen_line(State, State.cursor1)
+  end
+  State.selection1 = {}
+  -- delete everything between min (inclusive) and max (exclusive)
+  Text.clear_screen_line_cache(State, minl)
+  local min_offset = Text.offset(State.lines[minl].data, minp)
+  local max_offset = Text.offset(State.lines[maxl].data, maxp)
+  if minl == maxl then
+--?     print('minl == maxl')
+    State.lines[minl].data = State.lines[minl].data:sub(1, min_offset-1)..State.lines[minl].data:sub(max_offset)
+    return
+  end
+  assert(minl < maxl)
+  local rhs = State.lines[maxl].data:sub(max_offset)
+  for i=maxl,minl+1,-1 do
+    table.remove(State.lines, i)
+    table.remove(State.line_cache, i)
+  end
+  State.lines[minl].data = State.lines[minl].data:sub(1, min_offset-1)..rhs
+end
+
+function Text.selection(State)
+  if State.selection1.line == nil then return end
+  -- min,max = sorted(State.selection1,State.cursor1)
+  local minl,minp = State.selection1.line,State.selection1.pos
+  local maxl,maxp = State.cursor1.line,State.cursor1.pos
+  if minl > maxl then
+    minl,maxl = maxl,minl
+    minp,maxp = maxp,minp
+  elseif minl == maxl then
+    if minp > maxp then
+      minp,maxp = maxp,minp
+    end
+  end
+  local min_offset = Text.offset(State.lines[minl].data, minp)
+  local max_offset = Text.offset(State.lines[maxl].data, maxp)
+  if minl == maxl then
+    return State.lines[minl].data:sub(min_offset, max_offset-1)
+  end
+  assert(minl < maxl)
+  local result = {State.lines[minl].data:sub(min_offset)}
+  for i=minl+1,maxl-1 do
+    if State.lines[i].mode == 'text' then
+      table.insert(result, State.lines[i].data)
+    end
+  end
+  table.insert(result, State.lines[maxl].data:sub(1, max_offset-1))
+  return table.concat(result, '\n')
+end