Testing rectangular area operations

rectarea.py

'''
Rectangular Area Operations

This is a collection of test cases for the DEC rectangular area operations.
For each test, the top half of the screen shows the expected output, while the
bottom half shows the actual output.

NB: The expected output is based on the documentation in the DEC STD-070 manual
but has not yet been confirmed on any of the actual DEC terminals.
'''

import sys
selected_test = sys.argv[1] if len(sys.argv) > 1 else None
test_attrs = '1;4;7;33;41'

def write(s):
  if hasattr(sys.stdout, 'buffer'):
    sys.stdout.buffer.write(s.encode('latin1'))
  else:
    sys.stdout.write(s)

def fill(x,y,w,h,c,attrs = ''):
  if attrs != None: write('\033[%sm' % attrs)
  for i in range(h):
    write('\033[%d;%dH' % (y+i,x))
    write(c * w)

def decaln():
  write('\033[m\033[H\033#8')


class TestGroup:
  group_number = 0

  def __init__(self, name, test_setup = None):
    TestGroup.group_number += 1
    self.group_number = TestGroup.group_number
    self.group_name = name
    self.test_setup = test_setup
    self.test_number = 0
    self.active_test = None
    self.double_width_lines = None

  def __del__(self):
    self.end_last_test()
    write('\033[m\033[H\033[J')

  def new_test(self, name):
    self.test_number += 1
    self.test_id = '%d.%d' % (self.group_number, self.test_number) 
    if not self.is_selected(): return False
    self.end_last_test()
    self.test_setup()
    self.active_test = '%s %s: %s' % (self.test_id, self.group_name, name)
    return True

  def reset_double_width(self, *lines):
    self.double_width_lines = lines

  def is_selected(self):
    if selected_test == None: return True
    if selected_test == self.test_id: return True
    return self.test_id.startswith(selected_test+'.')

  def end_last_test(self):
    if self.active_test:
      write('\033[m\033[H')
      write('%s\033[K' % self.active_test)
      write('\033[999C\033[7DEXPECTED')
      write('\033[13H')
      write('%s\033[K' % self.active_test)
      write('\033[999C\033[5DACTUAL')
      write('\r')
      sys.stdout.flush()
      sys.stdin.readline()
      if self.double_width_lines:
        for row in self.double_width_lines:
          write('\033[%dH\033#5' % row)
        self.double_width_lines = None
      self.active_test = None


def test_decfra():
  def test_setup():
    decaln()
    write('\033[%sm' % test_attrs)
  g = TestGroup('DECFRA', test_setup)

  if g.new_test('Basic functionality'):
    '''
    STD070: When this control is received, the terminal fills rectangular area
    of character positions defined by Pt, Pl, Pb, and Pr, replacing both the
    character and the rendition present in those character positions with the
    character defined by the decimal value of Pch and the current renditions
    set through the SGR command.
    '''
    write('\033[42;16;27;22;54$x')
    # Expected output
    fill(27, 4, 28, 7, '*', test_attrs)

  if g.new_test('Default parameters'):
    '''
    STD070: Default values are Pch = 32, Pt = 1, Pb = last-line-of-page, PI = 1,
    and Pr = last-column-of-page. 
    '''
    write('\033[;16;1;19;80$x')
    write('\033[32;20$x')
    # Expected output
    fill(1, 4, 80, 9, ' ', test_attrs)

  if g.new_test('Invalid parameters'):
    '''
    STD070: The Pch parameter may be a decimal value from 32 to 126, or from 160 
    160 to 255. If the value of Pch is not in the  above range, the command is
    ignored. Pt must be less or equal to Pb, and Pl must be less than or equal
    to Pr, otherwise the entire control function is ignored. 
    '''
    write('\033[42;16;80;22;71$x') # Ignored, Pl > Pr
    write('\033[42;22;1;16;10$x') # Ignored, Pt > Pb
    test_chars = [31,32,126,0,160,255,145]
    for i,ch in enumerate(test_chars):
      write('\033[%d;%d;27;%d;54$x' % (ch,i+16,i+16))
    # Expected output
    for i,ch in enumerate(test_chars):
      if ch not in [31,145]:  # 31 and 145 ignored
        if ch == 0: ch = 32   # 0 is the same as default (32)
        fill(27, 4+i, 28, 1, chr(ch), test_attrs)

  if g.new_test('Origin mode'):
    '''
    STD070: The coordinates of the rectangular area are affected by the setting
    of Origin Mode. This control is not otherwise affected by the margins.
    '''
    write('\033[17;20r') # Margins 17 to 20
    write('\033[?6h') # Origin Mode enabled
    write('\033[65;6;33;8;48$x') # Clamped
    write('\033[66;2;36;6;45$x') # Clipped
    write('\033[?6l') # Origin Mode reset
    write('\033[67;16;39;22;42$x') # Not Clipped
    write('\033[r') # Margins reset
    # Expected output
    fill(39, 4, 4, 2, 'C', test_attrs)
    fill(36, 6, 1, 2, 'BBBCCCCBBB', test_attrs)
    fill(33, 8, 1, 1, 'AAABBBCCCCBBBAAA', test_attrs)
    fill(39, 9, 4, 2, 'C', test_attrs)

  if g.new_test('Double-width/height lines'):
    '''
    STD070: If the rectangular area contains both single and double width lines,
    the area affected may not appear rectangular on the display.
    '''
    write('\033[16H\033#3')
    write('\033[17H\033#4')
    write('\033[18H\033#6')
    write('\033[42;16;27;22;54$x')
    # Expected output
    fill(27, 4, 28, 7, '*', test_attrs)
    write('\033[4H\033#3')
    write('\033[5H\033#4')
    write('\033[6H\033#6')
    g.reset_double_width(4,5,6,16,17,18)

  if g.new_test('Overflowing page boundary'):
    '''
    STD070: If a value exceeds the width or height of the active page, it is
    treated as the width or height of the active page.
    '''
    write('\033[42;19;41;9999;9999$x')
    # Expected output
    fill(41, 7, 40, 6, '*', test_attrs)

  if g.new_test('Character set translation'):
    '''
    STD070: The decimal value refers to the character in the current GL and GR
    "in-use" character table, which is used to fill the specified rectangular
    area.
    '''
    write('\033(0')
    write('\033[110;16;27;22;54$x')
    # Expected output
    fill(27, 4, 28, 7, 'n', test_attrs)
    write('\033(B')
    pass


def test_decera():
  erase_attrs = '0;45'
  def test_setup():
    fill(1, 1, 80, 24, 'E', test_attrs)
    write('\033[0;4;7;36;45m')
  g = TestGroup('DECERA', test_setup)

  if g.new_test('Basic functionality'):
    '''
    STD070: When this control is received, the terminal erases the rectangular
    area of character positions defined by Pt, Pl, Pb, and Pr, clearing all
    character attributes. When an area is erased, all characters are replaced 
    with the Space character (2/0).
    '''
    write('\033[16;27;22;54$z')
    # Expected output
    fill(27, 4, 28, 7, ' ', erase_attrs)

  if g.new_test('Default parameters'):
    '''
    STD070: Default values are Pt = 1, Pb = last-line-of-page, Pl = 1, and Pr =
    last-column-of-page.
    '''
    write('\033[16$z')
    # Expected output
    fill(1, 4, 80, 9, ' ', erase_attrs)

  if g.new_test('Invalid parameters'):
    '''
    STD070: Pt must be less or equal to Pb, and Pl must be less than or equal
    to Pr, otherwise the entire control function is ignored.
    '''
    write('\033[16;80;22;71$z') # Ignored, Pl > Pr
    write('\033[22;1;16;10$z') # Ignored, Pt > Pb
    write('\033[18;38;20;43$z')
    # Expected output
    fill(38, 6, 6, 3, ' ', erase_attrs)

  if g.new_test('Origin mode'):
    '''
    STD070: The coordinates of the rectangular area are affected by the setting
    of Origin Mode. This control is not otherwise affected by the margins.
    '''
    write('\033[17;20r') # Margins 17 to 20
    write('\033[?6h') # Origin Mode enabled
    write('\033[6;33;8;48$z') # Clamped
    write('\033[2;36;6;45$z') # Clipped
    write('\033[?6l') # Origin Mode reset
    write('\033[16;39;22;42$z') # Not Clipped
    write('\033[r') # Margins reset
    # Expected output
    fill(39, 4, 4, 2, ' ', erase_attrs)
    fill(36, 6, 10, 2, ' ', None)
    fill(33, 8, 16, 1, ' ', None)
    fill(39, 9, 4, 2, ' ', None)

  if g.new_test('Double-width/height lines'):
    '''
    STD070: If the rectangular area contains both single and double width lines,
    the area affected may not appear rectangular on the display.
    '''
    write('\033[16H\033#3')
    write('\033[17H\033#4')
    write('\033[18H\033#6')
    write('\033[16;27;22;54$z')
    # Expected output
    fill(27, 4, 28, 7, ' ', erase_attrs)
    write('\033[4H\033#3')
    write('\033[5H\033#4')
    write('\033[6H\033#6')
    g.reset_double_width(4,5,6,16,17,18)

  if g.new_test('Overflowing page boundary'):
    '''
    STD070: If a value exceeds the width or height of the active page, it is
    treated as the width or height of the active page.
    '''
    write('\033[19;41;9999;9999$z')
    # Expected output
    fill(41, 7, 40, 6, ' ', erase_attrs)


def test_decsera():
  def diagonal(y):
    for i in range(9):
      write('\033[%d;%dHEE' % (y+i,34+i*2))
  def test_setup():
    fill(1, 1, 80, 24, 'E', test_attrs)
    write('\033[1"q')
    diagonal(16)
    write('\033[0"q')
    write('\033[m')
  g = TestGroup('DECSERA', test_setup)

  if g.new_test('Basic functionality'):
    '''
    STD070: When a character is erased, it is replaced with the Space character
    (2/0). This sequence does not change or clear any video character attributes
    (SGR or DECSCA)
    '''
    write('\033[16;27;22;54${')
    # Expected output
    fill(27, 4, 28, 7, ' ', test_attrs)
    diagonal(4)

  if g.new_test('Default parameters'):
    '''
    STD070: Default values are Pt = 1, Pb = last-line-of-page, Pl = 1, and Pr =
    last-column-of-page.
    '''
    write('\033[16${')
    # Expected output
    fill(1, 4, 80, 9, ' ', test_attrs)
    diagonal(4)

  if g.new_test('Invalid parameters'):
    '''
    STD070: Pt must be less or equal to Pb, and Pl must be less than or equal
    to Pr, otherwise the entire control function is ignored.
    '''
    write('\033[16;80;22;71${') # Ignored, Pl > Pr
    write('\033[22;1;16;10${') # Ignored, Pt > Pb
    write('\033[18;38;20;43${')
    # Expected output
    fill(38, 6, 6, 3, ' ', test_attrs)
    diagonal(4)

  if g.new_test('Origin mode'):
    '''
    STD070: The coordinates of the rectangular area are affected by the setting
    of Origin Mode. This control is not otherwise affected by the margins.
    '''
    write('\033[17;20r') # Margins 17 to 20
    write('\033[?6h') # Origin Mode enabled
    write('\033[6;33;8;48${') # Clamped
    write('\033[2;36;6;45${') # Clipped
    write('\033[?6l') # Origin Mode reset
    write('\033[16;39;22;42${') # Not Clipped
    write('\033[r') # Margins reset
    # Expected output
    fill(39, 4, 4, 2, ' ', test_attrs)
    fill(36, 6, 10, 2, ' ', None)
    fill(33, 8, 16, 1, ' ', None)
    fill(39, 9, 4, 2, ' ', None)
    diagonal(4)

  if g.new_test('Double-width/height lines'):
    '''
    STD070: If the rectangular area contains both single and double width lines,
    the area affected may not appear rectangular on the display.
    '''
    write('\033[16H\033#3')
    write('\033[17H\033#4')
    write('\033[18H\033#6')
    write('\033[16;27;22;54${')
    # Expected output
    fill(27, 4, 28, 7, ' ', test_attrs)
    diagonal(4)
    write('\033[4H\033#3')
    write('\033[5H\033#4')
    write('\033[6H\033#6')
    g.reset_double_width(4,5,6,16,17,18)

  if g.new_test('Overflowing page boundary'):
    '''
    STD070: If a value exceeds the width or height of the active page, it is
    treated as the width or height of the active page.
    '''
    write('\033[19;41;9999;9999${')
    # Expected output
    fill(41, 7, 40, 6, ' ', test_attrs)
    diagonal(4)


def test_deccra():
  def pattern(x, y, h = 3, clipped = False):
    for i in range(h):
      write('\033[%d;%dH***' % (y+i,x))
      if not clipped or i == 1:
        write('\033[22mooo\033[1m')
  def test_setup():
    decaln()
    write('\033[%sm' % test_attrs)
    pattern(38, 18)
  g = TestGroup('DECCRA', test_setup)

  if g.new_test('Basic functionality'):
    '''
    STD070: the terminal copies the character values and attributes in the
    specified rectangular area of character positions defined by Pts, Pls, Pbs,
    and Prs on the specified page Pps, to the area specified by the coordinate
    Ptd, Pld on the specified page Ppd. 
    '''
    write('\033[18;38;20;43;1;20;42;1$v')
    write('\033[20;42;22;47;1;16;34;1$v')
    # Expected output
    pattern(38, 6)
    pattern(42, 8)
    pattern(34, 4)

  if g.new_test('Default parameters'):
    '''
    STD070: Default values are Pts = 1, Pls = 1, Pbs = last-line-of-page, Prs =
    last-column-of-page, Pps = 1, Ptd = 1, Pld = 1, and Ppd = 1. 
    '''
    write('\033[;;;;;2;3$v')
    write('\033[3;5;21;45$v')
    # Expected output
    pattern(40, 7)
    pattern(36, 5)
    
  if g.new_test('Invalid parameters'):
    '''
    STD070: Pts must be less or equal to Pbs, and Pls must be less than or equal
    to Prs, otherwise the entire control function is ignored. 
    '''
    write('\033[18;38;20;43;1;20;42;1$v')
    write('\033[20;42;22;47;1;16;34;1$v')
    write('\033[16;47;23;34;1;16;1;1$v') # Ignored, Pls > Prs
    write('\033[23;34;16;47;1;16;67;1$v') # Ignored, Pbs > Pts
    # Expected output
    pattern(38, 6)
    pattern(42, 8)
    pattern(34, 4)

  if g.new_test('Origin mode'):
    '''
    STD070: The coordinates of the rectangular area are affected by the setting
    of Origin Mode. This control is not otherwise affected by the margins.
    '''
    write('\033[17;19r') # Margins 17 to 19
    write('\033[?6h') # Origin Mode enabled
    write('\033[6;38;8;43;1;1;28;1$v') # Clamped Src
    write('\033[3;38;5;43;1;2;29;1$v') # Clipped
    write('\033[2;38;4;43;1;5;30;1$v') # Clamped Dst
    write('\033[?6l') # Origin Mode reset
    write('\033[18;38;20;43;1;19;47;1$v') # Not Clipped
    write('\033[r') # Margins reset
    # Expected output
    pattern(38, 6)
    pattern(47, 7)
    pattern(28, 5, h=1)
    pattern(29, 6, h=1)
    pattern(30, 7, h=1)

  if g.new_test('Double-width/height lines'):
    '''
    STD070: If the rectangular area contains both single and double width lines,
    the area copied FROM may not appear rectangular on the display. Text copied
    to the destination area take on the line attributes of that area.
    '''
    write('\033[18H\033#6')
    write('\033[20H\033#6')
    write('\033[18;38;20;43;1;20;44;1$v')
    write('\033[18;38;20;43;1;16;32;1$v')
    # Expected output
    pattern(38, 6)
    pattern(44, 8, clipped=True)
    pattern(32, 4, clipped=True)
    write('\033[6H\033#6')
    write('\033[8H\033#6')
    g.reset_double_width(6,8,18,20)

  if g.new_test('Overflowing page boundary'):
    '''
    STD070: If a value exceeds the width or height of the active page, it is 
    treated as the width or height of the active page. If the destination
    rectangle specified is partially off of the Page, clipping of information
    will occur.
    '''
    write('\033[18;38;999;999;1;17;36;1$v')
    write('\033[17;36;999;999;1;19;40;1$v')
    # Expected output
    pattern(36, 5)
    pattern(40, 7)

  if g.new_test('Copying between pages'):
    '''
    STD070: the terminal copies the character values and attributes in the
    specified rectangular area ... on the specified page Pps, to the area ...
    on the specified page Ppd. 
    '''
    write('\033[2 P\033[14H\033[m\033[J\033[1 P')
    write('\033[18;38;20;43;1;18;38;2$v')
    write('\033[16;34;22;47;2;17;39;1$v')
    write('\033[16;34;22;47;2;15;29;1$v')
    # Expected output
    write('\033[%sm' % test_attrs)
    fill(29, 3, 14, 7, ' ')
    fill(39, 5, 14, 7, ' ')
    write('\033[%sm' % test_attrs)
    pattern(33, 5)
    pattern(43, 7)


def test_deccara():
  attrs = '1;4;7'
  def test_setup():
    decaln()
    write('\033[2*x')
  g = TestGroup('DECCARA', test_setup)

  if g.new_test('Basic functionality'):
    '''
    STD070: This sequence changes the video attributes for all of the character
    positions in a rectangular area without altering any characters in those
    positions.
    '''
    write('\033[16;27;22;54;%s$r' % attrs)
    # Expected output
    fill(27, 4, 28, 7, 'E', attrs)

  if g.new_test('Default parameters'):
    '''
    STD070: Default values are Pt = 1, Pb = last-line-of-page, Pl = 1, and Pr =
    last-column-of-page. The default for the video attribute parameters, if no
    valid subsequent parameter is received, is 0, which will clear all video 
    attributes in the specified area.
    '''
    write('\033[16;;;;%s$r' % attrs)
    write('\033[18;27;22;54$r')
    # Expected output
    fill(1, 4, 80, 9, 'E', attrs)
    fill(27, 6, 28, 5, 'E')

  if g.new_test('Invalid parameters'):
    '''
    STD070: Pt must be less or equal to Pb, and Pl must be less than or equal
    to Pr, otherwise the entire control function is ignored.
    '''
    write('\033[16;80;22;71;%s$r' % attrs) # Ignored, Pl > Pr
    write('\033[22;1;16;10;%s$r' % attrs) # Ignored, Pt > Pb
    write('\033[18;38;20;43;%s$r' % attrs)
    # Expected output
    fill(38, 6, 6, 3, 'E', attrs)

  if g.new_test('Origin mode'):
    '''
    STD070: The coordinates of the rectangular area are affected by the current
    setting of Origin Mode. This control is not otherwise affected by the
    margins.
    '''
    write('\033[17;20r') # Margins 17 to 20
    write('\033[?6h') # Origin Mode enabled
    write('\033[6;33;8;48;%s$r' % attrs) # Clamped
    write('\033[2;36;6;45;%s$r' % attrs) # Clipped
    write('\033[?6l') # Origin Mode reset
    write('\033[16;39;22;42;%s$r' % attrs) # Not Clipped
    write('\033[r') # Margins reset
    # Expected output
    fill(39, 4, 4, 2, 'E', attrs)
    fill(36, 6, 10, 2, 'E', None)
    fill(33, 8, 16, 1, 'E', None)
    fill(39, 9, 4, 2, 'E', None)

  if g.new_test('Double-width/height lines'):
    '''
    STD070: If the rectangular area contains both single and double width lines,
    the area affected may not appear rectangular on the display.
    '''
    write('\033[16H\033#3')
    write('\033[17H\033#4')
    write('\033[18H\033#6')
    write('\033[16;27;22;54;%s$r' % attrs)
    # Expected output
    fill(27, 4, 28, 7, 'E', attrs)
    write('\033[4H\033#3')
    write('\033[5H\033#4')
    write('\033[6H\033#6')
    g.reset_double_width(4,5,6,16,17,18)

  if g.new_test('Overflowing page boundary'):
    '''
    STD070: If a value exceeds the width or height of the active page, it is
    treated as the width or height of the active page.
    '''
    write('\033[19;41;9999;9999;%s$r' % attrs)
    # Expected output
    fill(41, 7, 40, 6, 'E', attrs)


def test_decrara():
  def test_setup():
    decaln()
    write('\033[2*x')
  g = TestGroup('DECRARA', test_setup)
  
  if g.new_test('Basic functionality'):
    '''
    STD070: This sequence reverses one or more video attributes for all of the
    character positions in a rectangular area without altering any characters in
    those positions.
    '''
    write('\033[16;27;22;54;1;4;7$t')
    # Expected output
    fill(27, 4, 28, 7, 'E', '1;4;7')

  if g.new_test('Default parameters'):
    '''
    STD070: Default values are Pt = 1, Pb = last-line-of-page, Pl = 1, and Pr =
    last-column-of-page.
    '''
    write('\033[16;;;;1;4;7$t')
    # Expected output
    fill(1, 4, 80, 9, 'E', '1;4;7')

  if g.new_test('Invalid parameters'):
    '''
    STD070: Pt must be less or equal to Pb, and Pl must be less than or equal
    to Pr, otherwise the entire control function is ignored. There is no default
    for the video attribute parameters, if no valid subsequent parameter is
    received, the command is ignored. 
    '''
    write('\033[16;80;22;71;1;4;7$t') # Ignored, Pl > Pr
    write('\033[22;1;16;10;1;4;7$t') # Ignored, Pt > Pb
    write('\033[16;27;17;54$t') # Ignored, no attribute parameters
    write('\033[18;38;20;43;1;4;7$t')
    # Expected output
    fill(38, 6, 6, 3, 'E', '1;4;7')

  if g.new_test('Origin mode'):
    '''
    STD070: The coordinates of the rectangular area are affected by the current
    setting of Origin Mode. This control is not otherwise affected by the
    margins.
    '''
    write('\033[17;20r') # Margins 17 to 20
    write('\033[?6h') # Origin Mode enabled
    write('\033[6;33;8;48;1;4;7$t') # Clamped
    write('\033[2;36;6;45;1;4;7$t') # Clipped
    write('\033[?6l') # Origin Mode reset
    write('\033[16;39;22;42;1;4;7$t') # Not Clipped
    write('\033[r') # Margins reset
    # Expected output
    fill(39, 4, 4, 2, 'E', '1;4;7')
    fill(36, 6, 3, 2, 'E', None)
    fill(43, 6, 3, 2, 'E', None)
    fill(33, 8, 3, 1, 'E', None)
    fill(46, 8, 3, 1, 'E', None)
    fill(39, 8, 4, 3, 'E', None)

  if g.new_test('Double-width/height lines'):
    '''
    STD070: If the rectangular area contains both single and double width lines,
    the area affected may not appear rectangular on the display.
    '''
    write('\033[16H\033#3')
    write('\033[17H\033#4')
    write('\033[18H\033#6')
    write('\033[16;27;22;54;1;4;7$t')
    # Expected output
    fill(27, 4, 28, 7, 'E', '1;4;7')
    write('\033[4H\033#3')
    write('\033[5H\033#4')
    write('\033[6H\033#6')
    g.reset_double_width(4,5,6,16,17,18)

  if g.new_test('Overflowing page boundary'):
    '''
    STD070: If a value exceeds the width or height of the active page, it is
    treated as the width or height of the active page.
    '''
    write('\033[19;41;9999;9999;1;4;7$t')
    # Expected output
    fill(41, 7, 40, 6, 'E', '1;4;7')


def test_attributes():
  color = ';33;41'
  all = '0;1;4;7'+color
  def test_setup():
    decaln()
    write('\033[2*x') # Rectangle mode
    fill(31,18,6,3,'*',all)
    fill(45,18,6,3,'*',None)
  g = TestGroup('Attributes', test_setup)

  '''
  DECCARA: The default, if no valid subsequent parameter is received, is 0.
  DECRARA: There is no default. If no valid subsequent parameter is received,
           the command is ignored.
  Both:    When multiple parameters are used, they are cumulative.
  '''
  test_cases = [
    ('',     'Default'),
    ('0',   'All Off / Reverse All (0)'),
    ('1',   'Increased Intensity (1)'),
    ('4',   'Underscore (4)'),
    ('7',   'Negative Image (7)'),
    ('22',  'Normal Intensity (22)'),
    ('24',  'No Underline (24)'),
    ('27',  'Positive Image (27)'),
    ('4;7', 'Underscore + Negative (4;7)'),
    ('0;7', 'All Off + Negative (0;7)'),
    (';7',  'Default + Negative (0;7)'),
    ('7;27','Negative + Positive (7;27)'),
    ('44',  'Blue Background (44)'),
    ('32',  'Green Foreground (32)'),
  ]

  def apply(src, add):
    src = set([int(n) for n in src.split(';')])
    if add == '': add = '0'
    for n in add.split(';'):
      n = int(n) if n else 0
      if n == 0:
        src.clear()
      elif n == 22:
        src.discard(1)
      elif n in [24,27]:
        src.discard(n-20)
      else:
        if n//10 == 3: src = set(i for i in src if i//10 != 3)
        if n//10 == 4: src = set(i for i in src if i//10 != 4)
        src.add(n)
    return ';'.join(['0'] + [str(n) for n in src if n])
  def reverse(src, rev):
    src = set([int(n) for n in src.split(';') if n != '0'])
    if rev:
      all_rendition = [1,2,3,4,5,6,7,8,9,21,53]
      for n in rev.split(';'):
        if n in ['','0']:
          expanded = all_rendition
        else:
          expanded = [int(n)]
        for n in expanded:
          if n in src:
            src.discard(n)
          elif n in all_rendition:
            src.add(n)
    return ';'.join(['0'] + [str(n) for n in src if n])

  for attrs,description in test_cases:
    if g.new_test(description):
      semiattrs = ';'+attrs if attrs else attrs
      write('\033[16;27;22;40%s$r' % semiattrs)
      write('\033[16;41;22;54%s$t' % semiattrs)
      # Expected output
      a1 = apply('0', attrs)
      a2 = apply(all, attrs)
      fill(27,4,14,7,'E',a1)
      fill(31,6,6,3,'*',a2)
      a1 = reverse('0', attrs)
      a2 = reverse(all, attrs)
      fill(41,4,14,7,'E',a1)
      fill(45,6,6,3,'*',a2)


def test_decsace():
  attrs = '1;4;7'
  def test_setup():
    decaln()
  g = TestGroup('DECSACE', test_setup)
  
  if g.new_test('Basic functionality'):
    write('\033[1*x') # Stream
    write('\033[16;34;17;47;%s$r' % attrs);
    write('\033[2*x') # Rectangle
    write('\033[18;34;20;47;%s$r' % attrs);
    write('\033[0*x') # Stream
    write('\033[21;34;22;47;%s$r' % attrs);
    # Expected output
    fill(34,4,47,1,'E','0;'+attrs)
    fill(1,5,47,1,'E',None)
    fill(34,6,14,3,'E',None)
    fill(34,9,47,1,'E',None)
    fill(1,10,47,1,'E',None)

  if g.new_test('Default parameter'):
    write('\033[2*x') # Start with 2 (rectangle) and see if
    write('\033[*x')  # the default (stream) overrides that.
    write('\033[16;34;22;47;%s$r' % attrs);
    # Expected output
    fill(34,4,47,1,'E','0;'+attrs)
    fill(1,5,80,5,'E',None)
    fill(1,10,47,1,'E',None)

  if g.new_test('Invalid parameters'):
    write('\033[1*x')
    write('\033[15;34;17;33;%s$r' % attrs); # Ignored, Pl > Pr
    write('\033[1*x')
    write('\033[3*x') # Ignored, Ps > 2
    write('\033[17;34;19;47;%s$r' % attrs);
    write('\033[2*x')
    write('\033[3*x') # Ignored, Ps > 2
    write('\033[20;34;21;47;%s$r' % attrs);
    # Expected output
    fill(34,5,47,1,'E','0;'+attrs)
    fill(1,6,80,1,'E',None)
    fill(1,7,47,1,'E',None)
    fill(34,8,14,2,'E',None)

  if g.new_test('Unoccupied positions (stream)'):
    write('\033[18;39H\033[4@') # ECH unoccupied
    write('\033[19;39H\033[2K    ') # EL unoccupied + occupied spaces
    write('\033[20;39H\033[4@') # ECH unoccupied
    write('\033[1*x')
    write('\033[16;34;19;40;%s$r' % attrs);
    write('\033[19;41;22;47;%s$t' % attrs);
    # Expected output
    fill(1,7,80,1,' ')
    fill(34,4,47,1,'E','0;'+attrs)
    fill(1,5,80,2,'E',None)
    fill(1,8,80,2,'E',None)
    fill(1,10,47,1,'E',None)
    fill(39,7,4,1,' ',None)
    fill(39,6,4,1,' ','0')
    fill(39,8,4,1,' ',None)

  if g.new_test('Unoccupied positions (rectangle)'):
    write('\033[18;39H\033[4@') # ECH unoccupied
    write('\033[19;39H\033[2K    ') # EL unoccupied + occupied spaces
    write('\033[20;39H\033[4@') # ECH unoccupied
    write('\033[2*x')
    write('\033[16;34;22;40;%s$r' % attrs);
    write('\033[16;41;22;47;%s$t' % attrs);
    # Expected output
    fill(1,7,80,1,' ')
    fill(34,4,14,3,'E','0;'+attrs)
    fill(34,7,14,3,' ',None)
    fill(34,8,14,3,'E',None)
    fill(39,6,4,1,' ',None)
    fill(39,8,4,1,' ',None)


# Try and make sure we're using ISO 2022 encoding.
write('\033%@')
sys.stdout.flush()

# Make sure Erase Color Mode is reset.
write('\033[?117l')

test_decfra()
test_decera()
test_decsera()
test_deccra()
test_deccara()
test_decrara()
test_attributes()
test_decsace()

VT420 V1.3

Using the Python code from gist commit a79a282bf5bbde82a7aed1aaaf93dc9690e4571e dated 2022-10-01.

Deviations in tests 1.3, 1.4, 2.4, 3.4, 4.4, 4.5, 5.4, 6.4, 8.3.

Replaced images with links so that each reader can choose whether the Web browser downloads the large files.

1 DECFRA

1.1 DECFRA: Basic functionality

1.2 DECFRA: Default parameters

1.3 DECFRA: Invalid parameters ⚠ deviation

1.4 DECFRA: Origin mode ⚠ deviation

1.5 DECFRA: Double-width/height lines

1.6 DECFRA: Overflowing page boundary

1.7 DECFRA: Character set translation

2 DECERA

2.1 DECERA: Basic functionality

2.2 DECERA: Default parameters

2.3 DECERA: Invalid parameters

2.4 DECERA: Origin mode ⚠ deviation

2.5 DECERA: Double-width/height lines

2.6 DECERA: Overflowing page boundary

3 DECSERA

3.1 DECSERA: Basic functionality

3.2 DECSERA: Default parameters

3.3 DECSERA: Invalid parameters

3.4 DECSERA: Origin mode ⚠ deviation

3.5 DECSERA: Double-width/height lines

3.6 DECSERA: Overflowing page boundary

4 DECCRA

4.1 DECCRA: Basic functionality

4.2 DECCRA: Default parameters

4.3 DECCRA: Invalid parameters

4.4 DECCRA: Origin mode ⚠ deviation

4.5 DECCRA: Double-width/height lines ⚠ deviation

4.6 DECCRA: Overflowing page boundary

4.7 DECCRA: Copying between pages

5 DECCARA

5.1 DECCARA: Basic functionality

5.2 DECCARA: Default parameters

5.3 DECCARA: Invalid parameters

5.4 DECCARA: Origin mode ⚠ deviation

5.5 DECCARA: Double-width/height lines

5.6 DECCARA: Overflowing page boundary

6 DECRARA

6.1 DECRARA: Basic functionality

6.2 DECRARA: Default parameters

6.3 DECRARA: Invalid parameters

6.4 DECRARA: Origin mode ⚠ deviation

6.5 DECRARA: Double-width/height lines

6.6 DECRARA: Overflowing page boundary

7 Attributes

7.1 Attributes: Default

7.2 Attributes: All Off / Reverse All (0) 🔅 blinking dark phase

7.2 Attributes: All Off / Reverse All (0) 🔆 blinking bright phase

7.3 Attributes: Increased Intensity (1)

7.4 Attributes: Underscore (4)

7.5 Attributes: Negative Image (7)

7.6 Attributes: Normal Intensity (22)

7.7 Attributes: No Underline (24)

7.8 Attributes: Positive Image (27)

7.9 Attributes: Underscore + Negative (4;7)

7.10 Attributes: All Off + Negative (0;7) 🔅 blinking dark phase

7.10 Attributes: All Off + Negative (0;7) 🔆 blinking bright phase

7.11 Attributes: Default + Negative (0;7) 🔅 blinking dark phase

7.11 Attributes: Default + Negative (0;7) 🔆 blinking bright phase

7.12 Attributes: Negative + Positive (7;27)

7.13 Attributes: Blue Background (44), but VT420 does not support colors

7.14 Attributes: Green Foreground (32), but VT420 does not support colors

8 DECSACE

8.1 DECSACE: Basic functionality

8.2 DECSACE: Default parameter

8.3 DECSACE: Invalid parameters ⚠ deviation

8.4 DECSACE: Unoccupied positions (stream)

8.5 DECSACE: Unoccupied positions (rectangle)

@KalleOlaviNiemitalo This is brilliant! Thank you so much!

The 1.3 is deviation was not unexpected - it could have gone either way from my reading of the docs. And 8.3 is working exactly as documented, but I didn't think it made sense, so I had assumed it might have been a mistake in the docs.

The x.4 origin tests are a bit of a surprise though - the docs clearly state that these controls are not affected by the margins (other than determining the origin), so I wasn't expecting them to be clipped. But maybe I misinterpreted what they meant. Everything else is clipped by margins, so this behavior is not unreasonable.

And 4.5 was really interesting - I don't think any of the TEs I looked at matched that behavior. But in retrospect it makes sense.

So I've got a few things to fix in my implementation, but I think this give me all the information I need. I'm not entirely sure about the 4.4 case - whether that is explained by margin clipping or there's more to figure out - but hopefully that'll become clearer once I get back into the code.

Once again, thank you so much!

I hope the overly large image files don’t blow up your GitHub invoice.

Linking back to microsoft/terminal#14112 for reference.

This is amazing.

And 8.3 is working exactly as documented, but I didn't think it made sense, so I had assumed it might have been a mistake in the docs.

Maybe the behaviour was originally unintended, and DEC chose to keep and document it in case any software depends on it. If so, I think it reduces the risk that DEC terminals other than VT420, or other versions of VT420, might behave differently.

@DHowett, some tests (including 1.2, 1.5, 1.6, and 2.2) show the plastic frame of the terminal diffusely reflecting the light emitted from nearby areas of bright-background characters. Would it be feasible to have such an effect in the retro terminal shader of Windows Terminal?

FYI, I've corrected the expected results for 1.3, 4.5, and 8.3 (also slightly adjusting the output of 8.3).

The margin tests are going to need more work, though. Now that I know they're meant to be clipped, I've realised there are a couple more edge cases we need to cover. So to start with I've redesigned the 1.4 test to try and figure out how exactly those margins work. Once I know how that has turned out, I'll do similar redesigns for the other x.4 tests, but in the meantime I've at least corrected their current results.

@KalleOlaviNiemitalo When you have a chance, I'd be grateful if you could do updated screenshots for 1.3, 1.4, 4.5, and 8.3, but don't bother with the other x.4 tests until I've had a chance to redo them properly.

Maybe the behaviour was originally unintended, and DEC chose to keep and document it in case any software depends on it.

That's possible. I'd be curious to see whether the VT525 works the same way. For now, though, since you've confirmed the documentation at least matches the VT420, that's the behavior I intend to emulate.

When you have a chance

Not before Wednesday evening, so don’t hesitate to edit until then.

I got a differently-wired cable, but flow control still doesn't seem to work right, so I cannot use high bit rates.

@KalleOlaviNiemitalo I've done another update with redesigned test cases for the remaining origin mode tests. I'm not certain my "expected" output is correct, but it's my best guess of how the margin clipping works.

So at this point the cases that need retesting include 1.3, 1.4, 2.4, 3.4, 4.4, 4.5, 5.4, 6.4, and 8.3. However, if you find that 1.4 doesn't match my expected output, there's probably no need to capture the remaining x.4 cases, because they're all likely to fail in the same way, and I'm going to need to update them all again anyway.

I got a differently-wired cable, but flow control still doesn't seem to work right, so I cannot use high bit rates.

I'm not sure if your VT420 works the same way as a VT340, but hackerb9 made a bunch of notes on the VT340 flow control which may be of help to you (see here).

Cables and flow control

I run this on Linux with an FTDI-based USB serial adapter that supports XON/XOFF, RTS/CTS, and DTR/DSR; but the termios API in Linux (unlike DCB in Windows) does not support DTR/DSR for flow control, nor does the driver have a private ioctl for that. XON/XOFF mostly works but it reserves ^Q and ^S and is not supported in all applications, so I hope I can configure stty crtscts -ixon -ixoff in Linux and connect a suitable signal from VT420 to CTS.

Between the null modem cable and the 25-pin serial connector of the VT420, I have a 9-pin to 25-pin adapter wired in the normal way:

9-pin		25-pin (VT420)
1 DCD	→	8 RLSD (To VT420)
2 RXD	→	3 RXD (To VT420)
3 TXD	←	2 TXD (From VT420)
4 DTR	←	20 DTR (From VT420)
5 GND	=	7 SGND
6 DSR	→	6 DSR (To VT420)
7 RTS	←	4 RTS (From VT420)
8 CTS	→	5 CTS (To VT420)
9 RI	→	22
NC	→	12 SPDI (To VT420)
NC	←	23 SPDS (From VT420)

Of the signals output by the VT420, either RTS or DTR might be usable for controlling the flow of data from the host to VT420, but I'll need to check with an oscilloscope.

My first null modem cable is wired like this:

VT420		host
1 DCD	←	7 RTS
2 RXD	←	3 TXD
3 TXD	→	2 RXD
4 DTR	→	6 DSR and 8 CTS
5 GND	=	5 GND
6 DSR and 8 CTS	←	4 DTR
7 RTS	→	1 DCD
9 RI	↔︎	9 RI

My second null modem cable is wired like this (9 RI not connected):

VT420		host
2 RXD	←	3 TXD
3 TXD	→	2 RXD
4 DTR	→	6 DSR and 1 DCD
5 GND	=	5 GND
6 DSR and 1 DCD	←	4 DTR
7 RTS	→	8 CTS
8 CTS	←	7 RTS

It seems I haven't got hardware flow control to work with either of these; text is corrupted in bursts. However, the second cable is easy to disassemble so that I should be able to measure the signals (do they change at all?) and rewire as needed.

I'm afraid I can't give you any useful advice on the hardware side of things, because this is way beyond my skill level, but I've found another reference that might be useful in the VT420 installation manual.
https://vt100.net/docs/vt420-uu/appendixc.html

VT420 V1.3

Using the Python code from gist commit 27a75caa0723039c352cf54352cd98aa7b446249 dated 2022-10-21.

All of the following appear to match up.

1 DECFRA

1.3 DECFRA: Invalid parameters

1.4 DECFRA: Origin mode

2 DECERA

2.4 DECERA: Origin mode

3 DECSERA

3.4 DECSERA: Origin mode

4 DECCRA

4.4 DECCRA: Origin mode

4.5 DECCRA: Double-width/height lines

5 DECCARA

5.4 DECCARA: Origin mode

6 DECRARA

6.4 DECRARA: Origin mode

7 Attributes

7.4 Attributes: Underscore (4)

8 DECSACE

8.3 DECSACE: Invalid parameters

8.4 DECSACE: Unoccupied positions (stream)

@KalleOlaviNiemitalo At last I've got it right! Thank you so much for doing this!

Oscilloscope attempt on flow control

I configured 9600 bps, no flow control in the host, Modem Control and Unlimited Transmit in the VT420. Connected the second null modem cable, ran yes in the host, and viewed the signals of the host-side connector using a Sinclair SC110 oscilloscope. The following voltages are not exact.

VT420	host	behaviour
2 RXD (To VT420)	3 TXD	±5 V data
3 TXD (From VT420)	2 RXD	-5 V stable
4 DTR (From VT420)	6 DSR and 1 DCD	+5 V stable
5 GND	5 GND	ground
6 DSR and 1 DCD (To VT420)	4 DTR	+5 V fuzzy
7 RTS (From VT420)	8 CTS	+5 V stable
8 CTS (To VT420)	7 RTS	+5 V fuzzy

Something like half of the characters transmitted by the host were displayed as reverse question marks, which I think means the input buffer of the VT420 could not keep up. The indicator status line of the VT420 was displaying "Modem: DSR".

Alas, neither RTS nor DTR appears suitable for flow control. I think the best way to get flow control without sacrificing ^Q and ^S would be to reverse engineer the SSU protocol and implement that in the host.

I think the best way to get flow control without sacrificing ^Q and ^S would be to reverse engineer the SSU protocol and implement that in the host.

If you want to attempt that, there is some discussion of the the protocol here:
https://paperlined.org/apps/terminals/control_characters/TDSMP.html

They say the protocol was patented, and in theory you should be able to work it out from those patents, but the links they gave appear to be dead now. I'm sure there must be somewhere you can look them up though.

One can still search for the patent numbers 4791566 and 5165020 at Patent Public Search | USPTO.

IIUC, https://ppubs.uspto.gov/pubwebapp/external.html?q=(%225165020%22).pn.%20OR%20(%224791566%22).pn. should be a link to such a search, but I couldn't get that to work.

I think I've found them on Google Patents:
https://patents.google.com/patent/US4791566/en
https://patents.google.com/patent/US5165020/en

These patents do not describe how the commands and their parameters are encoded. Perhaps it can be figured out by trial and error. (A log of the communication with the official SSU software would be easier to analyze, but my AlphaStation 500 is not in good condition and lacks OpenVMS. Community licenses are available but Community License Agreement §2.e. forbids reverse engineering.)

A log of the communication with the official SSU software would be easier to analyze

Yeah, the more I think about it having a log of both sides of the communication is probably essential. There's really not that much to go on in those patents.