center-formatting broken with certain escape sequences

[anarcat]

it seems that the "center" alignment can get confused if there is some escape sequences in a column.

for example, this program will generate this misaligned table:

[997]anarcat@angela:undertime$ ./undertime.py --start 7 --end 20 --date "in two weeks, at 15:00" America/Montreal US/Pacific Europe/London Australia/Melbourne
┌───────┬────────────┬───────────────┬─────────────────────┐
│  EST  │ US/Pacific │ Europe/London │ Australia/Melbourne │
├───────┼────────────┼───────────────┼─────────────────────┤
│ 00:00 │   21:00    │     05:00     │        16:00        │
│ 01:00 │   22:00    │     06:00     │        17:00        │
│ 02:00 │   23:00    │     07:00     │        18:00        │
│ 03:00 │   00:00    │     08:00     │        19:00        │
│ 04:00 │   01:00    │     09:00     │        20:00        │
│ 05:00 │   02:00    │     10:00     │        21:00        │
│ 06:00 │   03:00    │     11:00     │        22:00        │
│ 07:00 │   04:00    │     12:00     │        23:00        │
│ 08:00 │   05:00    │     13:00     │        00:00        │
│ 09:00 │   06:00    │     14:00     │        01:00        │
│ 10:00 │    07:00   │     15:00     │        02:00        │
│ 11:00 │    08:00   │     16:00     │        03:00        │
│ 12:00 │    09:00   │     17:00     │        04:00        │
│ 13:00 │    10:00   │     18:00     │        05:00        │
│ 14:00 │    11:00   │     19:00     │        06:00        │
│ 15:00 │    12:00   │     20:00     │        07:00        │
│ 16:00 │    13:00   │     21:00     │        08:00        │
│ 17:00 │    14:00   │     22:00     │        09:00        │
│ 18:00 │    15:00   │     23:00     │        10:00        │
│ 19:00 │    16:00   │     00:00     │        11:00        │
│ 20:00 │    17:00   │     01:00     │        12:00        │
│ 21:00 │    18:00   │     02:00     │        13:00        │
│ 22:00 │    19:00   │     03:00     │        14:00        │
│ 23:00 │    20:00   │     04:00     │        15:00        │
└───────┴────────────┴───────────────┴─────────────────────┘

if the colors are disabled, the column is aligned fine:

$ ./undertime.py --start 7 --end 20 --date "in two weeks, at 15:00" America/Montreal US/Pacific Europe/London Australia/Melbourne --no-colors
┌───────┬────────────┬───────────────┬─────────────────────┐
│  EST  │ US/Pacific │ Europe/London │ Australia/Melbourne │
├───────┼────────────┼───────────────┼─────────────────────┤
│ 00:00 │   21:00    │     05:00     │        16:00        │
│ 01:00 │   22:00    │     06:00     │        17:00        │
│ 02:00 │   23:00    │     07:00     │        18:00        │
│ 03:00 │   00:00    │     08:00     │        19:00        │
│ 04:00 │   01:00    │     09:00     │        20:00        │
│ 05:00 │   02:00    │     10:00     │        21:00        │
│ 06:00 │   03:00    │     11:00     │        22:00        │
│ 07:00 │   04:00    │     12:00     │        23:00        │
│ 08:00 │   05:00    │     13:00     │        00:00        │
│ 09:00 │   06:00    │     14:00     │        01:00        │
│ 10:00 │   07:00    │     15:00     │        02:00        │
│ 11:00 │   08:00    │     16:00     │        03:00        │
│ 12:00 │   09:00    │     17:00     │        04:00        │
│ 13:00 │   10:00    │     18:00     │        05:00        │
│ 14:00 │   11:00    │     19:00     │        06:00        │
│ 15:00 │   12:00    │     20:00     │        07:00        │
│ 16:00 │   13:00    │     21:00     │        08:00        │
│ 17:00 │   14:00    │     22:00     │        09:00        │
│ 18:00 │   15:00    │     23:00     │        10:00        │
│ 19:00 │   16:00    │     00:00     │        11:00        │
│ 20:00 │   17:00    │     01:00     │        12:00        │
│ 21:00 │   18:00    │     02:00     │        13:00        │
│ 22:00 │   19:00    │     03:00     │        14:00        │
│ 23:00 │   20:00    │     04:00     │        15:00        │
└───────┴────────────┴───────────────┴─────────────────────┘

not sure what's going on here but it sure seems like the escape sequence calculations go wrong at some point.

PS: I understand this is not exactly a minimal test case but I'm a little tired right now and would rather document this issue at this point. Let me know if you need help minimizing the code or understanding how the table is created.

[mgedmin]

The correlation between colors and alignment becomes more apparent when you can see the colors:

[mgedmin]

Here's a failing unit test:

diff --git a/tests/test_width_and_alignment/test_align_and_pad_cell.py b/tests/test_width_and_alignment/test_align_and_pad_cell.py
index e0a928e..aa8bd27 100644
--- a/tests/test_width_and_alignment/test_align_and_pad_cell.py
+++ b/tests/test_width_and_alignment/test_align_and_pad_cell.py
@@ -74,6 +74,9 @@ from terminaltables.width_and_alignment import align_and_pad_cell
     ('蓝色', 'center', 6, [' 蓝色 ']),
     (u'שלום', 'center', 6, [u' \u05e9\u05dc\u05d5\u05dd ']),
     (u'معرب', 'center', 6, [u' \u0645\u0639\u0631\u0628 ']),
+
+    ('00:00', 'center', 8, ['  00:00 ']),
+    (colored('00:00', 'blue'), 'center', 8, ['  \x1b[34m00:00\x1b[0m ']),
 ])
 def test_width(string, align, width, expected):
     """Test width and horizontal alignment.

I don't know which padding you prefer when centering requires left and right padding to be different, but it should be the same for colored and non-colored text.

[KwadroNaut]

Nice to see there's a Pull Request to fix this. Anything you need, @Robpol86 to integrate this?

[anarcat]

@KwadroNaut i suspect the maintainer here might need a little help, see #70

[anarcat]

FWIW, i ended up switching to tabulate which doesn't have that problem and supports more output formats.