Merge lines.love

18 files changed, 116 insertions, 250 deletions

diff --git a/app.lua b/app.lua
index 59dff31..b883a75 100644
--- a/app.lua
+++ b/app.lua
@@ -137,7 +137,7 @@ function App.run_tests_and_initialize()
   Test_errors = {}
   App.run_tests()
   if #Test_errors > 0 then
-    error('There were test failures:\n\n'..table.concat(Test_errors))
+    error(('There were %d test failures:\n\n%s'):format(#Test_errors, table.concat(Test_errors)))
   end
   App.disable_tests()
   App.initialize_globals()
@@ -210,16 +210,8 @@ function App.wait_fake_time(t)
   App.time = App.time + t
 end
 
--- LÖVE's Text primitive retains no trace of the string it was created from,
--- so we'll wrap it for our tests.
---
--- This implies that we need to hook any operations we need on Text objects.
-function App.newText(font, s)
-  return {type='text', data=s, text=love.graphics.newText(font, s)}
-end
-
 function App.width(text)
-  return text.text:getWidth()
+  return love.graphics.getFont():getWidth(text)
 end
 
 function App.screen.draw(obj, x,y)
@@ -381,7 +373,7 @@ end
 -- prepend file/line/test
 function prepend_debug_info_to_test_failure(test_name, err)
   local err_without_line_number = err:gsub('^[^:]*:[^:]*: ', '')
-  local stack_trace = debug.traceback('', --[[stack frame]]4)
+  local stack_trace = debug.traceback('', --[[stack frame]]5)
   local file_and_line_number = stack_trace:gsub('stack traceback:\n', ''):gsub(': .*', '')
   local full_error = file_and_line_number..':'..test_name..' -- '..err_without_line_number
 --?   local full_error = file_and_line_number..':'..test_name..' -- '..err_without_line_number..'\t\t'..stack_trace:gsub('\n', '\n\t\t')
@@ -423,9 +415,7 @@ function App.disable_tests()
   App.screen.move = love.window.setPosition
   App.screen.position = love.window.getPosition
   App.screen.print = love.graphics.print
-  App.newText = love.graphics.newText
   App.screen.draw = love.graphics.draw
-  App.width = function(text) return text:getWidth() end
   if Current_app == nil or Current_app == 'run' then
     App.open_for_reading = function(filename) return io.open(filename, 'r') end
     App.open_for_writing = function(filename) return io.open(filename, 'w') end
diff --git a/commands.lua b/commands.lua
index b1ac5ab..512992d 100644
--- a/commands.lua
+++ b/commands.lua
@@ -43,21 +43,19 @@ function source.draw_menu_bar()
 end
 
 function add_hotkey_to_menu(s)
-  local s_text = to_text(s)
-  local width = App.width(s_text)
+  local width = App.width(s)
   if Menu_cursor > App.screen.width - 30 then
     return
   end
   App.color(Menu_command_color)
-  App.screen.draw(s_text, Menu_cursor,5)
+  App.screen.print(s, Menu_cursor,5)
   Menu_cursor = Menu_cursor + width + 30
 end
 
 function source.draw_file_navigator()
   App.color(Menu_command_color)
-  local filter_text = to_text(File_navigation.filter)
-  App.screen.draw(filter_text, 5, 5)
-  draw_cursor(5 + App.width(filter_text), 5)
+  App.screen.print(File_navigation.filter, 5, 5)
+  draw_cursor(5 + App.width(File_navigation.filter), 5)
   if File_navigation.num_lines == nil then
     File_navigation.num_lines = source.num_lines_for_file_navigator(File_navigation.candidates)
   end
@@ -97,7 +95,7 @@ function source.num_lines_for_file_navigator(candidates)
   local result = 1
   local x = 5
   for i,filename in ipairs(candidates) do
-    local width = App.width(to_text(filename))
+    local width = App.width(filename)
     if x + width > App.screen.width - 5 then
       result = result+1
       x = 5 + width
@@ -109,8 +107,7 @@ function source.num_lines_for_file_navigator(candidates)
 end
 
 function add_file_to_menu(x,y, s, cursor_highlight)
-  local s_text = to_text(s)
-  local width = App.width(s_text)
+  local width = App.width(s)
   if x + width > App.screen.width - 5 then
     y = y + Editor_state.line_height
     x = 5
@@ -125,7 +122,7 @@ function add_file_to_menu(x,y, s, cursor_highlight)
     end
   })
   App.color(Menu_command_color)
-  App.screen.draw(s_text, x,y)
+  App.screen.print(s, x,y)
   x = x + width + 30
   return x,y
 end
@@ -189,8 +186,7 @@ function log_render.file_navigator_state(o, x,y, w)
   local x2,y2 = 0,0
   local width = 0
   for i,filename in ipairs(o.files) do
-    local filename_text = to_text(filename)
-    width = App.width(filename_text)
+    width = App.width(filename)
     if x2 + width > App.screen.width - 5 then
       y2 = y2 + Editor_state.line_height
       x2 = 0
@@ -207,8 +203,7 @@ function log_render.file_navigator_state(o, x,y, w)
   local x3,y3 = 0,y  -- x3 is relative, y3 is absolute
   local width = 0
   for i,filename in ipairs(o.files) do
-    local filename_text = to_text(filename)
-    width = App.width(filename_text)
+    width = App.width(filename)
     if x3 + width > App.screen.width - 5 then
       y3 = y3 + Editor_state.line_height
       x3 = 0
@@ -219,7 +214,7 @@ function log_render.file_navigator_state(o, x,y, w)
     end
     if x3 >= menu_xmin and x3 + width < menu_xmax then
       App.color(Menu_command_color)
-      App.screen.draw(filename_text, x + x3-menu_xmin, y3)
+      App.screen.print(filename, x + x3-menu_xmin, y3)
     end
     x3 = x3 + width + 30
   end
@@ -246,7 +241,7 @@ end
 function file_coord(index)
   local y,x = Menu_status_bar_height, 5
   for i,filename in ipairs(File_navigation.candidates) do
-    local width = App.width(to_text(filename))
+    local width = App.width(filename)
     if x + width > App.screen.width - 5 then
       y = y + Editor_state.line_height
       x = 5
@@ -264,7 +259,7 @@ function file_index(fy, fx, fwidth)
   local y,x = Menu_status_bar_height, 5
   local best_guess, best_guess_x, best_guess_width
   for i,filename in ipairs(File_navigation.candidates) do
-    local width = App.width(to_text(filename))
+    local width = App.width(filename)
     if x + width > App.screen.width - 5 then
       y = y + Editor_state.line_height
       x = 5
diff --git a/drawing.lua b/drawing.lua
index 99193c6..5af25fb 100644
--- a/drawing.lua
+++ b/drawing.lua
@@ -60,14 +60,13 @@ function Drawing.draw(State, line_index, y)
         if State.current_drawing_mode == 'name' and i == line.pending.target_point then
           -- create a faint red box for the name
           App.color(Current_name_background_color)
-          local name_text
-          -- TODO: avoid computing name width on every repaint
+          local name_width
           if p.name == '' then
-            name_text = State.em
+            name_width = App.width('m')
           else
-            name_text = App.newText(love.graphics.getFont(), p.name)
+            name_width = App.width(p.name)
           end
-          love.graphics.rectangle('fill', x,y, App.width(name_text), State.line_height)
+          love.graphics.rectangle('fill', x,y, name_width, State.line_height)
         end
       end
     end
diff --git a/edit.lua b/edit.lua
index 36cce6e..ac60aa8 100644
--- a/edit.lua
+++ b/edit.lua
@@ -21,7 +21,7 @@ function edit.initialize_state(top, left, right, font_height, line_height)  -- c
     -- rendering wrapped text lines needs some additional short-lived data per line:
     --   startpos, the index of data the line starts rendering from, can only be >1 for topmost line on screen
     --   starty, the y coord in pixels the line starts rendering from
-    --   fragments: snippets of rendered love.graphics.Text, guaranteed to not straddle screen lines
+    --   fragments: snippets of the line guaranteed to not straddle screen lines
     --   screen_line_starting_pos: optional array of grapheme indices if it wraps over more than one screen line
     line_cache = {},
 
@@ -52,7 +52,6 @@ function edit.initialize_state(top, left, right, font_height, line_height)  -- c
 
     font_height = font_height,
     line_height = line_height,
-    em = App.newText(love.graphics.getFont(), 'm'),  -- widest possible character width
 
     top = top,
     left = math.floor(left),
@@ -68,7 +67,6 @@ function edit.initialize_state(top, left, right, font_height, line_height)  -- c
 
     -- search
     search_term = nil,
-    search_text = nil,
     search_backup = nil,  -- stuff to restore when cancelling search
   }
   return result
@@ -220,7 +218,6 @@ function edit.text_input(State, t)
 --?   print('text input', t)
   if State.search_term then
     State.search_term = State.search_term..t
-    State.search_text = nil
     Text.search_next(State)
   else
     for _,line_cache in ipairs(State.line_cache) do line_cache.starty = nil end  -- just in case we scroll
@@ -241,20 +238,17 @@ function edit.keychord_press(State, chord, key)
     for _,line_cache in ipairs(State.line_cache) do line_cache.starty = nil end  -- just in case we scroll
     if chord == 'escape' then
       State.search_term = nil
-      State.search_text = nil
       State.cursor1 = State.search_backup.cursor
       State.screen_top1 = State.search_backup.screen_top
       State.search_backup = nil
       Text.redraw_all(State)  -- if we're scrolling, reclaim all fragments to avoid memory leaks
     elseif chord == 'return' then
       State.search_term = nil
-      State.search_text = nil
       State.search_backup = nil
     elseif chord == 'backspace' then
       local len = utf8.len(State.search_term)
       local byte_offset = Text.offset(State.search_term, len)
       State.search_term = string.sub(State.search_term, 1, byte_offset-1)
-      State.search_text = nil
     elseif chord == 'down' then
       State.cursor1.pos = State.cursor1.pos+1
       Text.search_next(State)
@@ -268,7 +262,6 @@ function edit.keychord_press(State, chord, key)
       cursor={line=State.cursor1.line, pos=State.cursor1.pos},
       screen_top={line=State.screen_top1.line, pos=State.screen_top1.pos},
     }
-    assert(State.search_text == nil)
   -- zoom
   elseif chord == 'C-=' then
     edit.update_font_settings(State, State.font_height+2)
@@ -359,7 +352,6 @@ function edit.update_font_settings(State, font_height)
   State.font_height = font_height
   love.graphics.setFont(love.graphics.newFont(State.font_height))
   State.line_height = math.floor(font_height*1.3)
-  State.em = App.newText(love.graphics.getFont(), 'm')
   Text_cache = {}
 end
 
diff --git a/help.lua b/help.lua
index 145692f..d91be3c 100644
--- a/help.lua
+++ b/help.lua
@@ -147,5 +147,5 @@ function current_shape(State, shape)
 end
 
 function bullet_indent()
-  return App.width(to_text('* '))
+  return App.width('* ')
 end
diff --git a/log_browser.lua b/log_browser.lua
index 46d84c0..b128ab7 100644
--- a/log_browser.lua
+++ b/log_browser.lua
@@ -98,21 +98,20 @@ function log_browser.draw(State)
       local xright = render_stack_right_margin(State, line_index, line, y)
       if line.section_name then
         App.color(Section_border_color)
-        local section_text = to_text(line.section_name)
         if line.section_begin then
           local sectiony = y+Section_border_padding_vertical
           love.graphics.line(xleft,sectiony, xleft,y+State.line_height)
           love.graphics.line(xright,sectiony, xright,y+State.line_height)
           love.graphics.line(xleft,sectiony, xleft+50-2,sectiony)
-          love.graphics.draw(section_text, xleft+50,y)
-          love.graphics.line(xleft+50+App.width(section_text)+2,sectiony, xright,sectiony)
+          love.graphics.print(line.section_name, xleft+50,y)
+          love.graphics.line(xleft+50+App.width(line.section_name)+2,sectiony, xright,sectiony)
         else assert(line.section_end)
           local sectiony = y+State.line_height-Section_border_padding_vertical
           love.graphics.line(xleft,y, xleft,sectiony)
           love.graphics.line(xright,y, xright,sectiony)
           love.graphics.line(xleft,sectiony, xleft+50-2,sectiony)
-          love.graphics.draw(section_text, xleft+50,y)
-          love.graphics.line(xleft+50+App.width(section_text)+2,sectiony, xright,sectiony)
+          love.graphics.print(line.section_name, xleft+50,y)
+          love.graphics.line(xleft+50+App.width(line.section_name)+2,sectiony, xright,sectiony)
         end
       else
         if type(line.data) == 'string' then
@@ -148,7 +147,7 @@ function render_stack_left_margin(State, line_index, line, y)
       love.graphics.print(line.section_stack[i].name, x+State.font_height+5, y+5, --[[vertically]] math.pi/2)
     end
     if y > App.screen.height-log_browser.height(State, line_index) then
-      love.graphics.print(line.section_stack[i].name, x+State.font_height+5, App.screen.height-App.width(to_text(line.section_stack[i].name))-5, --[[vertically]] math.pi/2)
+      love.graphics.print(line.section_stack[i].name, x+State.font_height+5, App.screen.height-App.width(line.section_stack[i].name)-5, --[[vertically]] math.pi/2)
     end
   end
   return log_browser.left_margin(State, line)
@@ -163,7 +162,7 @@ function render_stack_right_margin(State, line_index, line, y)
       love.graphics.print(line.section_stack[i].name, x, y+5, --[[vertically]] math.pi/2)
     end
     if y > App.screen.height-log_browser.height(State, line_index) then
-      love.graphics.print(line.section_stack[i].name, x, App.screen.height-App.width(to_text(line.section_stack[i].name))-5, --[[vertically]] math.pi/2)
+      love.graphics.print(line.section_stack[i].name, x, App.screen.height-App.width(line.section_stack[i].name)-5, --[[vertically]] math.pi/2)
     end
   end
   return log_browser.right_margin(State, line)
diff --git a/run.lua b/run.lua
index d5b588a..eab1f8b 100644
--- a/run.lua
+++ b/run.lua
@@ -71,12 +71,10 @@ end
 function run.initialize_default_settings()
   local font_height = 20
   love.graphics.setFont(love.graphics.newFont(font_height))
-  local em = App.newText(love.graphics.getFont(), 'm')
-  run.initialize_window_geometry(App.width(em))
+  run.initialize_window_geometry(App.width('m'))
   Editor_state = edit.initialize_state(Margin_top, Margin_left, App.screen.width-Margin_right)
   Editor_state.font_height = font_height
   Editor_state.line_height = math.floor(font_height*1.3)
-  Editor_state.em = em
   Settings = run.settings()
 end
 
@@ -197,10 +195,6 @@ function run.key_release(key, scancode)
   return edit.key_release(Editor_state, key, scancode)
 end
 
--- use this sparingly
-function to_text(s)
-  if Text_cache[s] == nil then
-    Text_cache[s] = App.newText(love.graphics.getFont(), s)
-  end
-  return Text_cache[s]
+function width(s)
+  return love.graphics.getFont():getWidth(s)
 end
diff --git a/search.lua b/search.lua
index f7d4732..7d3d335 100644
--- a/search.lua
+++ b/search.lua
@@ -13,10 +13,7 @@ function Text.draw_search_bar(State)
   love.graphics.rectangle('line', 20, y-6, App.screen.width-40, h+2, 2,2)
   App.color(Text_color)
   App.screen.print(State.search_term, 25,y-5)
-  if State.search_text == nil then
-    State.search_text = App.newText(love.graphics.getFont(), State.search_term)
-  end
-  Text.draw_cursor(State, 25+App.width(State.search_text),y-5)
+  Text.draw_cursor(State, 25+App.width(State.search_term),y-5)
 end
 
 function Text.search_next(State)
diff --git a/select.lua b/select.lua
index b7cf65f..0050895 100644
--- a/select.lua
+++ b/select.lua
@@ -58,15 +58,12 @@ function Text.draw_highlight(State, line, x,y, pos, lo,hi)
       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)
+      lo_px = App.width(before)
     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)
+    love.graphics.rectangle('fill', x+lo_px,y, App.width(s),State.line_height)
     App.color(Text_color)
     return lo_px
   end
diff --git a/source.lua b/source.lua
index 9452e6b..c70f125 100644
--- a/source.lua
+++ b/source.lua
@@ -162,13 +162,11 @@ end
 function source.initialize_default_settings()
   local font_height = 20
   love.graphics.setFont(love.graphics.newFont(font_height))
-  local em = App.newText(love.graphics.getFont(), 'm')
-  source.initialize_window_geometry(App.width(em))
+  source.initialize_window_geometry(App.width('m'))
   Editor_state = edit.initialize_state(Margin_top, Margin_left, App.screen.width-Margin_right)
   Editor_state.filename = 'run.lua'
   Editor_state.font_height = font_height
   Editor_state.line_height = math.floor(font_height*1.3)
-  Editor_state.em = em
 end
 
 function source.initialize_window_geometry(em_width)
@@ -418,11 +416,3 @@ function source.key_release(key, scancode)
     return log_browser.keychord_press(Log_browser_state, chordkey, scancode)
   end
 end
-
--- use this sparingly
-function to_text(s)
-  if Text_cache[s] == nil then
-    Text_cache[s] = App.newText(love.graphics.getFont(), s)
-  end
-  return Text_cache[s]
-end
diff --git a/source_edit.lua b/source_edit.lua
index 2fc7e1b..5dabee9 100644
--- a/source_edit.lua
+++ b/source_edit.lua
@@ -54,7 +54,7 @@ function edit.initialize_state(top, left, right, font_height, line_height)  -- c
     -- rendering wrapped text lines needs some additional short-lived data per line:
     --   startpos, the index of data the line starts rendering from, can only be >1 for topmost line on screen
     --   starty, the y coord in pixels the line starts rendering from
-    --   fragments: snippets of rendered love.graphics.Text, guaranteed to not straddle screen lines
+    --   fragments: snippets of the line guaranteed to not straddle screen lines
     --   screen_line_starting_pos: optional array of grapheme indices if it wraps over more than one screen line
     line_cache = {},
 
@@ -88,7 +88,6 @@ function edit.initialize_state(top, left, right, font_height, line_height)  -- c
 
     font_height = font_height,
     line_height = line_height,
-    em = App.newText(love.graphics.getFont(), 'm'),  -- widest possible character width
 
     top = top,
     left = math.floor(left),
@@ -104,7 +103,6 @@ function edit.initialize_state(top, left, right, font_height, line_height)  -- c
 
     -- search
     search_term = nil,
-    search_text = nil,
     search_backup = nil,  -- stuff to restore when cancelling search
   }
   return result
@@ -325,7 +323,6 @@ function edit.text_input(State, t)
 --?   print('text input', t)
   if State.search_term then
     State.search_term = State.search_term..t
-    State.search_text = nil
     Text.search_next(State)
   elseif State.lines.current_drawing and State.current_drawing_mode == 'name' then
     local before = snapshot(State, State.lines.current_drawing_index)
@@ -356,20 +353,17 @@ function edit.keychord_press(State, chord, key)
     for _,line_cache in ipairs(State.line_cache) do line_cache.starty = nil end  -- just in case we scroll
     if chord == 'escape' then
       State.search_term = nil
-      State.search_text = nil
       State.cursor1 = State.search_backup.cursor
       State.screen_top1 = State.search_backup.screen_top
       State.search_backup = nil
       Text.redraw_all(State)  -- if we're scrolling, reclaim all fragments to avoid memory leaks
     elseif chord == 'return' then
       State.search_term = nil
-      State.search_text = nil
       State.search_backup = nil
     elseif chord == 'backspace' then
       local len = utf8.len(State.search_term)
       local byte_offset = Text.offset(State.search_term, len)
       State.search_term = string.sub(State.search_term, 1, byte_offset-1)
-      State.search_text = nil
     elseif chord == 'down' then
       State.cursor1.pos = State.cursor1.pos+1
       Text.search_next(State)
@@ -383,7 +377,6 @@ function edit.keychord_press(State, chord, key)
       cursor={line=State.cursor1.line, pos=State.cursor1.pos},
       screen_top={line=State.screen_top1.line, pos=State.screen_top1.pos},
     }
-    assert(State.search_text == nil)
   -- zoom
   elseif chord == 'C-=' then
     edit.update_font_settings(State, State.font_height+2)
@@ -515,7 +508,6 @@ function edit.update_font_settings(State, font_height)
   State.font_height = font_height
   love.graphics.setFont(love.graphics.newFont(State.font_height))
   State.line_height = math.floor(font_height*1.3)
-  State.em = App.newText(love.graphics.getFont(), 'm')
   Text_cache = {}
 end
 
diff --git a/source_file.lua b/source_file.lua
index 194ef9b..3adab1f 100644
--- a/source_file.lua
+++ b/source_file.lua
@@ -1,7 +1,5 @@
 -- primitives for saving to file and loading from file
 
-Fold = '\x1e'  -- ASCII RS (record separator)
-
 function file_exists(filename)
   local infile = App.open_for_reading(filename)
   if infile then
@@ -28,13 +26,7 @@ function load_from_file(infile)
       if line == '```lines' then  -- inflexible with whitespace since these files are always autogenerated
         table.insert(result, load_drawing(infile_next_line))
       else
-        local line_info = {mode='text'}
-        if line:find(Fold) then
-          _, _, line_info.data, line_info.dataB = line:find('([^'..Fold..']*)'..Fold..'([^'..Fold..']*)')
-        else
-          line_info.data = line
-        end
-        table.insert(result, line_info)
+        table.insert(result, {mode='text', data=line})
       end
     end
   end
@@ -54,10 +46,6 @@ function save_to_disk(State)
       store_drawing(outfile, line)
     else
       outfile:write(line.data)
-      if line.dataB and #line.dataB > 0 then
-        outfile:write(Fold)
-        outfile:write(line.dataB)
-      end
       outfile:write('\n')
     end
   end
@@ -147,11 +135,7 @@ function load_array(a)
     else
 --?       print('inserting text')
       local line_info = {mode='text'}
-      if line:find(Fold) then
-        _, _, line_info.data, line_info.dataB = line:find('([^'..Fold..']*)'..Fold..'([^'..Fold..']*)')
-      else
-        line_info.data = line
-      end
+      line_info.data = line
       table.insert(result, line_info)
     end
   end
diff --git a/source_select.lua b/source_select.lua
index 297a7bc..2298513 100644
--- a/source_select.lua
+++ b/source_select.lua
@@ -60,15 +60,12 @@ function Text.draw_highlight(State, line, x,y, pos, lo,hi)
       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)
+      lo_px = App.width(before)
     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)
+    love.graphics.rectangle('fill', x+lo_px,y, App.width(s),State.line_height)
     App.color(Text_color)
     return lo_px
   end
diff --git a/source_text.lua b/source_text.lua
index 4d13748..b68bf85 100644
--- a/source_text.lua
+++ b/source_text.lua
@@ -12,21 +12,20 @@ function Text.draw(State, line_index, y, startpos, hide_cursor)
   local x = State.left
   local pos = 1
   local screen_line_starting_pos = startpos
-  Text.compute_fragments(State, line_index)
+  Text.populate_screen_line_starting_pos(State, line_index)
   local pos = 1
   initialize_color()
   for _, f in ipairs(line_cache.fragments) do
     App.color(Text_color)
-    local frag, frag_text = f.data, f.text
-    select_color(frag)
-    local frag_len = utf8.len(frag)
---?     print('text.draw:', frag, 'at', line_index,pos, 'after', x,y)
+    select_color(f)
+    local frag_len = utf8.len(f)
+--?     print('text.draw:', f, 'at', line_index,pos, 'after', x,y)
     if pos < startpos then
       -- render nothing
---?       print('skipping', frag)
+--?       print('skipping', f)
     else
       -- render fragment
-      local frag_width = App.width(frag_text)
+      local frag_width = App.width(f)
       if x + frag_width > State.right then
         assert(x > State.left)  -- no overfull lines
         y = y + State.line_height
@@ -41,12 +40,11 @@ function Text.draw(State, line_index, y, startpos, hide_cursor)
         Text.draw_highlight(State, line, x,y, pos, lo,hi)
       end
       -- Make [[WikiWords]] (single word, all in one screen line) clickable.
-      local trimmed_word = rtrim(frag)  -- compute_fragments puts whitespace at the end
+      local trimmed_word = rtrim(f)  -- compute_fragments puts whitespace at the end
       if starts_with(trimmed_word, '[[') and ends_with(trimmed_word, ']]') then
         local filename = trimmed_word:gsub('^..(.*)..$', '%1')
         if source.link_exists(State, filename) then
-          local filename_text = App.newText(love.graphics.getFont(), filename)
-          button(State, 'link', {x=x+App.width(to_text('[[')), y=y, w=App.width(filename_text), h=State.line_height, color={1,1,1},
+          button(State, 'link', {x=x+App.width('[['), y=y, w=App.width(filename), h=State.line_height, color={1,1,1},
             icon = icon.hyperlink_decoration,
             onpress1 = function()
                          source.switch_to_file(filename)
@@ -54,7 +52,7 @@ function Text.draw(State, line_index, y, startpos, hide_cursor)
           })
         end
       end
-      App.screen.draw(frag_text, x,y)
+      App.screen.print(f, x,y)
       -- render cursor if necessary
       if line_index == State.cursor1.line then
         if pos <= State.cursor1.pos and pos + frag_len > State.cursor1.pos then
@@ -65,7 +63,7 @@ function Text.draw(State, line_index, y, startpos, hide_cursor)
               love.graphics.print(State.search_term, x+lo_px,y)
             end
           elseif Focus == 'edit' then
-            Text.draw_cursor(State, x+Text.x(frag, State.cursor1.pos-pos+1), y)
+            Text.draw_cursor(State, x+Text.x(f, State.cursor1.pos-pos+1), y)
             App.color(Text_color)
           end
         end
@@ -105,21 +103,18 @@ function Text.populate_screen_line_starting_pos(State, line_index)
   local x = State.left
   local pos = 1
   for _, f in ipairs(line_cache.fragments) do
-    local frag, frag_text = f.data, f.text
     -- render fragment
-    local frag_width = App.width(frag_text)
+    local frag_width = App.width(f)
     if x + frag_width > State.right then
       x = State.left
       table.insert(line_cache.screen_line_starting_pos, pos)
     end
     x = x + frag_width
-    local frag_len = utf8.len(frag)
-    pos = pos + frag_len
+    pos = pos + utf8.len(f)
   end
 end
 
 function Text.compute_fragments(State, line_index)
---?   print('compute_fragments', line_index, 'between', State.left, State.right)
   local line = State.lines[line_index]
   if line.mode ~= 'text' then return end
   local line_cache = State.line_cache[line_index]
@@ -130,35 +125,25 @@ function Text.compute_fragments(State, line_index)
   local x = State.left
   -- try to wrap at word boundaries
   for frag in line.data:gmatch('%S*%s*') do
-    local frag_text = App.newText(love.graphics.getFont(), frag)
-    local frag_width = App.width(frag_text)
---?     print('x: '..tostring(x)..'; frag_width: '..tostring(frag_width)..'; '..tostring(State.right-x)..'px to go')
+    local frag_width = App.width(frag)
     while x + frag_width > State.right do
---?       print(('checking whether to split fragment ^%s$ of width %d when rendering from %d'):format(frag, frag_width, x))
       if (x-State.left) < 0.8 * (State.right-State.left) then
---?         print('splitting')
         -- long word; chop it at some letter
         -- We're not going to reimplement TeX here.
         local bpos = Text.nearest_pos_less_than(frag, State.right - x)
---?         print('bpos', bpos)
         if bpos == 0 then break end  -- avoid infinite loop when window is too narrow
         local boffset = Text.offset(frag, bpos+1)  -- byte _after_ bpos
---?         print('space for '..tostring(bpos)..' graphemes, '..tostring(boffset-1)..' bytes')
         local frag1 = string.sub(frag, 1, boffset-1)
-        local frag1_text = App.newText(love.graphics.getFont(), frag1)
-        local frag1_width = App.width(frag1_text)
---?         print('extracting ^'..frag1..'$ of width '..tostring(frag1_width)..'px')
+        local frag1_width = App.width(frag1)
         assert(x + frag1_width <= State.right)
-        table.insert(line_cache.fragments, {data=frag1, text=frag1_text})
+        table.insert(line_cache.fragments, frag1)
         frag = string.sub(frag, boffset)
-        frag_text = App.newText(love.graphics.getFont(), frag)
-        frag_width = App.width(frag_text)
+        frag_width = App.width(frag)
       end
       x = State.left  -- new line
     end
     if #frag > 0 then
---?       print('inserting ^'..frag..'$ of width '..tostring(frag_width)..'px')
-      table.insert(line_cache.fragments, {data=frag, text=frag_text})
+      table.insert(line_cache.fragments, frag)
     end
     x = x + frag_width
   end
@@ -776,8 +761,7 @@ function Text.screen_line_width(State, line_index, i)
   else
     screen_line = string.sub(line.data, start_pos)
   end
-  local screen_line_text = App.newText(love.graphics.getFont(), screen_line)
-  return App.width(screen_line_text)
+  return App.width(screen_line)
 end
 
 function Text.screen_line_index(screen_line_starting_pos, pos)
@@ -865,15 +849,13 @@ function Text.x_after(s, pos)
   local offset = Text.offset(s, math.min(pos+1, #s+1))
   local s_before = s:sub(1, offset-1)
 --?   print('^'..s_before..'$')
-  local text_before = App.newText(love.graphics.getFont(), s_before)
-  return App.width(text_before)
+  return App.width(s_before)
 end
 
 function Text.x(s, pos)
   local offset = Text.offset(s, pos)
   local s_before = s:sub(1, offset-1)
-  local text_before = App.newText(love.graphics.getFont(), s_before)
-  return App.width(text_before)
+  return App.width(s_before)
 end
 
 function Text.to2(State, loc1)
diff --git a/source_undo.lua b/source_undo.lua
index 6023324..d3d5f0f 100644
--- a/source_undo.lua
+++ b/source_undo.lua
@@ -61,14 +61,9 @@ function snapshot(State, s,e)
   for i=s,e do
     local line = State.lines[i]
     if line.mode == 'text' then
-      table.insert(event.lines, {mode='text', data=line.data, dataB=line.dataB})
+      table.insert(event.lines, {mode='text', data=line.data})  -- I've forgotten: should we deepcopy(line.data)?
     elseif line.mode == 'drawing' then
-      local points=deepcopy(line.points)
---?       print('copying', line.points, 'with', #line.points, 'points into', points)
-      local shapes=deepcopy(line.shapes)
---?       print('copying', line.shapes, 'with', #line.shapes, 'shapes into', shapes)
-      table.insert(event.lines, {mode='drawing', h=line.h, points=points, shapes=shapes, pending={}})
---?       table.insert(event.lines, {mode='drawing', h=line.h, points=deepcopy(line.points), shapes=deepcopy(line.shapes), pending={}})
+      table.insert(event.lines, {mode='drawing', h=line.h, points=deepcopy(line.points), shapes=deepcopy(line.shapes), pending={}})
     else
       print(line.mode)
       assert(false)
diff --git a/text.lua b/text.lua
index 464ab85..35c98f5 100644
--- a/text.lua
+++ b/text.lua
@@ -4,64 +4,64 @@ Text = {}
 -- draw a line starting from startpos to screen at y between State.left and State.right
 -- return the final y, and position of start of final screen line drawn
 function Text.draw(State, line_index, y, startpos)
+--?   print('text.draw', line_index, y)
   local line = State.lines[line_index]
   local line_cache = State.line_cache[line_index]
   line_cache.starty = y
   line_cache.startpos = startpos
   -- wrap long lines
-  local x = State.left
-  local pos = 1
-  local screen_line_starting_pos = startpos
-  Text.compute_fragments(State, line_index)
-  for _, f in ipairs(line_cache.fragments) do
-    App.color(Text_color)
-    local frag, frag_text = f.data, f.text
-    local frag_len = utf8.len(frag)
---?     print('text.draw:', frag, 'at', line_index,pos, 'after', x,y)
+  local final_screen_line_starting_pos = startpos  -- track value to return
+  Text.populate_screen_line_starting_pos(State, line_index)
+  assert(#line_cache.screen_line_starting_pos >= 1)
+  for i=1,#line_cache.screen_line_starting_pos do
+    local pos = line_cache.screen_line_starting_pos[i]
     if pos < startpos then
       -- render nothing
---?       print('skipping', frag)
+--?       print('skipping', f)
     else
+      final_screen_line_starting_pos = pos
+      local f = Text.screen_line(line, line_cache, i)
+--?       print('text.draw:', f, 'at', line_index,pos, 'after', x,y)
+      local frag_len = utf8.len(f)
       -- render fragment
-      local frag_width = App.width(frag_text)
-      if x + frag_width > State.right then
-        assert(x > State.left)  -- no overfull lines
-        y = y + State.line_height
-        if y + State.line_height > App.screen.height then
-          return y, screen_line_starting_pos
-        end
-        screen_line_starting_pos = pos
-        x = State.left
-      end
       if State.selection1.line then
         local lo, hi = Text.clip_selection(State, line_index, pos, pos+frag_len)
-        Text.draw_highlight(State, line, x,y, pos, lo,hi)
+        Text.draw_highlight(State, line, State.left,y, pos, lo,hi)
       end
-      App.screen.draw(frag_text, x,y)
+      App.color(Text_color)
+      App.screen.print(f, State.left,y)
       -- render cursor if necessary
       if line_index == State.cursor1.line then
-        if pos <= State.cursor1.pos and pos + frag_len > State.cursor1.pos then
+        if pos <= State.cursor1.pos and pos + frag_len >= State.cursor1.pos then
           if State.search_term then
             if State.lines[State.cursor1.line].data:sub(State.cursor1.pos, State.cursor1.pos+utf8.len(State.search_term)-1) == State.search_term then
-              local lo_px = Text.draw_highlight(State, line, x,y, pos, State.cursor1.pos, State.cursor1.pos+utf8.len(State.search_term))
+              local lo_px = Text.draw_highlight(State, line, State.left,y, pos, State.cursor1.pos, State.cursor1.pos+utf8.len(State.search_term))
               App.color(Text_color)
-              love.graphics.print(State.search_term, x+lo_px,y)
+              love.graphics.print(State.search_term, State.left+lo_px,y)
             end
           else
-            Text.draw_cursor(State, x+Text.x(frag, State.cursor1.pos-pos+1), y)
+            Text.draw_cursor(State, State.left+Text.x(f, State.cursor1.pos-pos+1), y)
           end
         end
       end
-      x = x + frag_width
+      y = y + State.line_height
+      if y >= App.screen.height then
+        break
+      end
     end
-    pos = pos + frag_len
   end
-  if State.search_term == nil then
-    if line_index == State.cursor1.line and State.cursor1.pos == pos then
-      Text.draw_cursor(State, x, y)
-    end
+  return y - State.line_height, final_screen_line_starting_pos
+end
+
+function Text.screen_line(line, line_cache, i)
+  local pos = line_cache.screen_line_starting_pos[i]
+  local offset = Text.offset(line.data, pos)
+  if i >= #line_cache.screen_line_starting_pos then
+    return line.data:sub(offset)
   end
-  return y, screen_line_starting_pos
+  local endpos = line_cache.screen_line_starting_pos[i+1]-1
+  local end_offset = Text.offset(line.data, endpos)
+  return line.data:sub(offset, end_offset)
 end
 
 function Text.draw_cursor(State, x, y)
@@ -81,67 +81,34 @@ function Text.populate_screen_line_starting_pos(State, line_index)
   if line_cache.screen_line_starting_pos then
     return
   end
-  -- duplicate some logic from Text.draw
-  Text.compute_fragments(State, line_index)
   line_cache.screen_line_starting_pos = {1}
-  local x = State.left
+  local x = 0
   local pos = 1
-  for _, f in ipairs(line_cache.fragments) do
-    local frag, frag_text = f.data, f.text
-    -- render fragment
-    local frag_width = App.width(frag_text)
-    if x + frag_width > State.right then
-      x = State.left
-      table.insert(line_cache.screen_line_starting_pos, pos)
-    end
-    x = x + frag_width
-    local frag_len = utf8.len(frag)
-    pos = pos + frag_len
-  end
-end
-
-function Text.compute_fragments(State, line_index)
---?   print('compute_fragments', line_index, 'between', State.left, State.right)
-  local line = State.lines[line_index]
-  local line_cache = State.line_cache[line_index]
-  if line_cache.fragments then
-    return
-  end
-  line_cache.fragments = {}
-  local x = State.left
   -- try to wrap at word boundaries
   for frag in line.data:gmatch('%S*%s*') do
-    local frag_text = App.newText(love.graphics.getFont(), frag)
-    local frag_width = App.width(frag_text)
---?     print('x: '..tostring(x)..'; frag_width: '..tostring(frag_width)..'; '..tostring(State.right-x)..'px to go')
-    while x + frag_width > State.right do
---?       print(('checking whether to split fragment ^%s$ of width %d when rendering from %d'):format(frag, frag_width, x))
-      if (x-State.left) < 0.8 * (State.right-State.left) then
---?         print('splitting')
+    local frag_width = App.width(frag)
+--?     print('-- frag:', frag, pos, x, frag_width, State.width)
+    while x + frag_width > State.width do
+--?       print('frag:', frag, pos, x, frag_width, State.width)
+      if x < 0.8 * State.width then
         -- long word; chop it at some letter
         -- We're not going to reimplement TeX here.
-        local bpos = Text.nearest_pos_less_than(frag, State.right - x)
---?         print('bpos', bpos)
-        if bpos == 0 then break end  -- avoid infinite loop when window is too narrow
+        local bpos = Text.nearest_pos_less_than(frag, State.width - x)
+        -- everything works if bpos == 0, but is a little inefficient
+        pos = pos + bpos
         local boffset = Text.offset(frag, bpos+1)  -- byte _after_ bpos
---?         print('space for '..tostring(bpos)..' graphemes, '..tostring(boffset-1)..' bytes')
-        local frag1 = string.sub(frag, 1, boffset-1)
-        local frag1_text = App.newText(love.graphics.getFont(), frag1)
-        local frag1_width = App.width(frag1_text)
---?         print('extracting ^'..frag1..'$ of width '..tostring(frag1_width)..'px')
-        assert(x + frag1_width <= State.right)
-        table.insert(line_cache.fragments, {data=frag1, text=frag1_text})
         frag = string.sub(frag, boffset)
-        frag_text = App.newText(love.graphics.getFont(), frag)
-        frag_width = App.width(frag_text)
+--?         if bpos > 0 then
+--?           print('after chop:', frag)
+--?         end
+        frag_width = App.width(frag)
       end
-      x = State.left  -- new line
-    end
-    if #frag > 0 then
---?       print('inserting ^'..frag..'$ of width '..tostring(frag_width)..'px')
-      table.insert(line_cache.fragments, {data=frag, text=frag_text})
+--?       print('screen line:', pos)
+      table.insert(line_cache.screen_line_starting_pos, pos)
+      x = 0  -- new screen line
     end
     x = x + frag_width
+    pos = pos + utf8.len(frag)
   end
 end
 
@@ -687,8 +654,7 @@ function Text.screen_line_width(State, line_index, i)
   else
     screen_line = string.sub(line.data, start_pos)
   end
-  local screen_line_text = App.newText(love.graphics.getFont(), screen_line)
-  return App.width(screen_line_text)
+  return App.width(screen_line)
 end
 
 function Text.screen_line_index(screen_line_starting_pos, pos)
@@ -776,15 +742,13 @@ function Text.x_after(s, pos)
   local offset = Text.offset(s, math.min(pos+1, #s+1))
   local s_before = s:sub(1, offset-1)
 --?   print('^'..s_before..'$')
-  local text_before = App.newText(love.graphics.getFont(), s_before)
-  return App.width(text_before)
+  return App.width(s_before)
 end
 
 function Text.x(s, pos)
   local offset = Text.offset(s, pos)
   local s_before = s:sub(1, offset-1)
-  local text_before = App.newText(love.graphics.getFont(), s_before)
-  return App.width(text_before)
+  return App.width(s_before)
 end
 
 function Text.to2(State, loc1)
@@ -914,7 +878,6 @@ function Text.redraw_all(State)
 end
 
 function Text.clear_screen_line_cache(State, line_index)
-  State.line_cache[line_index].fragments = nil
   State.line_cache[line_index].screen_line_starting_pos = nil
 end
 
diff --git a/text_tests.lua b/text_tests.lua
index 25fda74..516e377 100644
--- a/text_tests.lua
+++ b/text_tests.lua
@@ -952,7 +952,7 @@ function test_pagedown_can_start_from_middle_of_long_wrapping_line()
   y = y + Editor_state.line_height
   App.screen.check(y, 'jkl ', 'screen:2')
   y = y + Editor_state.line_height
-  App.screen.check(y, 'mno ', 'screen:3')
+  App.screen.check(y, 'mn', 'screen:3')
 end
 
 function test_pagedown_never_moves_up()
diff --git a/undo.lua b/undo.lua
index 912c949..873feea 100644
--- a/undo.lua
+++ b/undo.lua
@@ -58,7 +58,7 @@ function snapshot(State, s,e)
   -- deep copy lines without cached stuff like text fragments
   for i=s,e do
     local line = State.lines[i]
-    table.insert(event.lines, {data=line.data})
+    table.insert(event.lines, {data=line.data})  -- I've forgotten: should we deepcopy(line.data)?
   end
   return event
 end