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Text.move_cursor_down_to_next_text_line_while_scrolling_again_if_necessary(State)
--? print(State.cursor1.line, State.cursor1.pos, State.screen_top1.line, State.screen_top1.pos)
--? print('pageup end')
end
function Text.pagedown(State)
--? print('pagedown')
Text.move_cursor_down_to_next_text_line_while_scrolling_again_if_necessary(State)
--? print('top now', State.screen_top1.line)
Text.redraw_all(State) -- if we're scrolling, reclaim all fragments to avoid memory leaks
--? print('pagedown end')
end
function Text.up(State)
local scroll_down = Text.le1(State.screen_bottom1, State.cursor1)
--? print('cursor is NOT at final screen line of its line')
local screen_line_starting_pos, screen_line_index = Text.pos_at_start_of_screen_line(State, State.cursor1)
Text.populate_screen_line_starting_pos(State, State.cursor1.line)
local new_screen_line_starting_pos = State.line_cache[State.cursor1.line].screen_line_starting_pos[screen_line_index+1]
--? print('switching pos of screen line at cursor from '..tostring(screen_line_starting_pos)..' to '..tostring(new_screen_line_starting_pos))
local new_screen_line_starting_byte_offset = Text.offset(State.lines[State.cursor1.line].data, new_screen_line_starting_pos)
local s = string.sub(State.lines[State.cursor1.line].data, new_screen_line_starting_byte_offset)
State.cursor1.pos = new_screen_line_starting_pos + Text.nearest_cursor_pos(s, State.cursor_x, State.left) - 1
--? print('cursor pos is now', State.cursor1.line, State.cursor1.pos)
if scroll_down then
--? print('scroll up preserving cursor')
Text.snap_cursor_to_bottom_of_screen(State)
--? print('screen top after:', State.screen_top1.line, State.screen_top1.pos)
end
end
--? print('=>', State.cursor1.line, State.cursor1.pos, State.screen_top1.line, State.screen_top1.pos, State.screen_bottom1.line, State.screen_bottom1.pos)
end
function Text.start_of_line(State)
return result
end
function Text.to1(State, loc2)
local result = {line=loc2.line, pos=loc2.screen_pos}
if loc2.screen_line > 1 then
result.pos = State.line_cache[loc2.line].screen_line_starting_pos[loc2.screen_line] + loc2.screen_pos - 1
end
return result
end
end
function Text.offset(s, pos1)
if pos1 == 1 then return 1 end
local result = utf8.offset(s, pos1)
if result == nil then
print(pos1, #s, s)
end
assert(result)
return result
end
function Text.previous_screen_line(State, loc2)
if loc2.screen_line > 1 then
return {line=loc2.line, screen_line=loc2.screen_line-1, screen_pos=1}
elseif loc2.line == 1 then
return loc2
end
end
-- resize helper
function Text.tweak_screen_top_and_cursor(State)
if State.screen_top1.pos == 1 then return end
Text.populate_screen_line_starting_pos(State, State.screen_top1.line)
local line = State.lines[State.screen_top1.line]
local line_cache = State.line_cache[State.screen_top1.line]
for i=2,#line_cache.screen_line_starting_pos do
local pos = line_cache.screen_line_starting_pos[i]
if pos == State.screen_top1.pos then
break
end
if pos > State.screen_top1.pos then
-- make sure screen top is at start of a screen line
local prev = line_cache.screen_line_starting_pos[i-1]
if State.screen_top1.pos - prev < pos - State.screen_top1.pos then
State.screen_top1.pos = prev
else
State.screen_top1.pos = pos
end
break
end
end
-- make sure cursor is on screen
if Text.lt1(State.cursor1, State.screen_top1) then
State.cursor1 = {line=State.screen_top1.line, pos=State.screen_top1.pos}
elseif State.cursor1.line >= State.screen_bottom1.line then
--? print('too low')
if Text.cursor_out_of_screen(State) then
--? print('tweak')
end
end
end
-- slightly expensive since it redraws the screen
function Text.cursor_out_of_screen(State)
App.draw()
return State.cursor_y == nil
-- this approach is cheaper and almost works, except on the final screen
-- where file ends above bottom of screen
--? local botpos = Text.pos_at_start_of_screen_line(State, State.cursor1)
--? local botline1 = {line=State.cursor1.line, pos=botpos}
--? return Text.lt1(State.screen_bottom1, botline1)
State.line_cache[line_index].screen_line_starting_pos = nil
end
function trim(s)
return s:gsub('^%s+', ''):gsub('%s+$', '')
end
function ltrim(s)
return s:gsub('^%s+', '')
end
function rtrim(s)
return s:gsub('%s+$', '')