bugfix: UTF-8 in compute_fragments

Dependencies

• [2] LXTTOB33 extract a couple of files
• [3] IMEJA43L snapshot
• [4] PFT5Y2ZY move
• [5] MDXGMZU2 disable all debug prints
• [6] R5OKMVVC fix a regression in line wrapping
• [7] QYIFOHW3 first test!
• [*] BULPIBEG beginnings of a module for the text editor
• [*] OTIBCAUJ love2d scaffold
• [*] IRV65LZP fold variables for screen dimensions into the app framework

Change contents

• edit in text_tests.lua at line 110
  [2.2452]

  [2.2452]
  + end

  +

  + function test_draw_wrapping_text_containing_non_ascii()

  + -- draw a long line containing non-ASCII

  + io.write('\ntest_draw_wrapping_text_containing_non_ascii')

  + App.screen.init{width=60, height=60}

  + Lines = load_array{'madam I’m adam', 'xyz'} -- notice the non-ASCII apostrophe

  + Line_width = App.screen.width

  + Cursor1 = {line=1, pos=1}

  + Screen_top1 = {line=1, pos=1}

  + Screen_bottom1 = {}

  + App.draw()

  + local y = Margin_top

  + App.screen.check(y, 'mada', 'F - test_draw_wrapping_text_containing_non_ascii/screen:1')

  + y = y + Line_height

  + App.screen.check(y, 'm I’', 'F - test_draw_wrapping_text_containing_non_ascii/screen:2')

  + y = y + Line_height

  + App.screen.check(y, 'm ad', 'F - test_draw_wrapping_text_containing_non_ascii/screen:3')
• replacement in text.lua at line 113
  [3.672]→[3.6847:6916](∅→∅),[3.6916]→[3.1529:1603](∅→∅),[3.1603]→[3.738:846](∅→∅),[3.6916]→[3.738:846](∅→∅),[3.738]→[3.738:846](∅→∅)
  − local b = Text.nearest_pos_less_than(frag, line_width - x)

  − assert(b > 0) -- avoid infinite loop when window is too narrow

  − --? print('space for '..tostring(b)..' graphemes')

  − local frag1 = string.sub(frag, 1, b)
  [3.672]

  [3.809]
  + local bpos = Text.nearest_pos_less_than(frag, line_width - x)

  + assert(bpos > 0) -- avoid infinite loop when window is too narrow

  + local boffset = utf8.offset(frag, bpos+1) -- byte _after_ bpos

  + assert(boffset)

  + --? print('space for '..tostring(bpos)..' graphemes, '..tostring(boffset)..' bytes')

  + local frag1 = string.sub(frag, 1, boffset-1)
• replacement in text.lua at line 125
  [3.1152]→[3.1152:1191](∅→∅)
  − frag = string.sub(frag, b+1)
  [3.1152]

  [3.952]
  + frag = string.sub(frag, boffset)
• edit in main.lua at line 197
  [11.337]

  [10.302]
  + --? love.graphics.setColor(0, 1, 0)

  + --? love.graphics.line(Line_width,0, Line_width,App.screen.height)