simplify cursor-on-screen check

edit.lua

@@ -134,7 +134,8 @@ function edit.draw(State)
     print(State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos)
     assert(false)
   end
-  State.cursor_y = -1
+  State.cursor_x = nil
+  State.cursor_y = nil
   local y = State.top
 --?   print('== draw')
   for line_index = State.screen_top1.line,#State.lines do
@@ -176,9 +177,6 @@ function edit.draw(State)
       assert(false)
     end
   end
-  if State.cursor_y == -1 then
-    State.cursor_y = App.screen.height
-  end
 --?   print('screen bottom: '..tostring(State.screen_bottom1.pos)..' in '..tostring(State.lines[State.screen_bottom1.line].data))
   if State.search_term then
     Text.draw_search_bar(State)
@@ -408,7 +406,7 @@ function edit.keychord_pressed(State, chord, key)
         Text.insert_at_cursor(State, c)
       end
     end
-    if Text.cursor_past_screen_bottom(State) then
+    if Text.cursor_out_of_screen(State) then
       Text.snap_cursor_to_bottom_of_screen(State, State.left, State.right)
     end
     schedule_save(State)

text.lua

@@ -528,7 +528,7 @@ function Text.end_of_line(State)
   State.cursor1.pos = utf8.len(State.lines[State.cursor1.line].data) + 1
   local botpos = Text.pos_at_start_of_cursor_screen_line(State)
   local botline1 = {line=State.cursor1.line, pos=botpos}
-  if Text.cursor_past_screen_bottom(State) then
+  if Text.cursor_out_of_screen(State) then
     Text.snap_cursor_to_bottom_of_screen(State)
   end
 end
@@ -577,7 +577,7 @@ function Text.word_right(State)
       break
     end
   end
-  if Text.cursor_past_screen_bottom(State) then
+  if Text.cursor_out_of_screen(State) then
     Text.snap_cursor_to_bottom_of_screen(State)
   end
 end
@@ -615,7 +615,7 @@ end
 
 function Text.right(State)
   Text.right_without_scroll(State)
-  if Text.cursor_past_screen_bottom(State) then
+  if Text.cursor_out_of_screen(State) then
     Text.snap_cursor_to_bottom_of_screen(State)
   end
 end
@@ -968,7 +968,7 @@ function Text.tweak_screen_top_and_cursor(State)
     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_past_screen_bottom(State) then
+    if Text.cursor_out_of_screen(State) then
 --?       print('tweak')
       State.cursor1 = {
           line=State.screen_bottom1.line,
@@ -979,9 +979,9 @@ function Text.tweak_screen_top_and_cursor(State)
 end
 
 -- slightly expensive since it redraws the screen
-function Text.cursor_past_screen_bottom(State)
+function Text.cursor_out_of_screen(State)
   App.draw()
-  return State.cursor_y >= App.screen.height - State.line_height
+  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_cursor_screen_line(State)