[Midnight Commander] #113: savannah: make tabs and trailing spaces visible

#113: savannah: make tabs and trailing spaces visible
 Reporter:  slavazanko  |       Owner:       
     Type:  defect      |      Status:  new  
 Priority:  major       |   Milestone:       
Component:  mc-core     |     Version:  4.6.1
 Keywords:              |    Blocking:       
Blockedby:              |  
 Original: http://savannah.gnu.org/bugs/?13146

 ||Submitted by:||Oswald Buddenhagen <ossi>||Submitted on:||Sat 21 May 2005
 07:25:17 PM UTC||
 ||Category:||Editor||Severity:||3 - Normal||
 ||Status:||In Progress||Privacy:||Public||
 ||Assigned to:||None||Open/Closed:||Open||
 ||Release:||current (CVS or snapshot)||Operating System:||All||

 Sun 06 Jul 2008 04:12:04 PM UTC, comment #24:

 I noticed I cannot just use the Unicode characters (like p->ch = 0xB7), as
 that does not take into account terminals that are not in UTF-8. But the
 fix is simple enough (p->ch = SLsmg_Is_Unicode ? 0xB7 : ".").

 BTW, I also implemented the MS Word-style "tabs", i.e. printing a right-
 arrow in the middle of a tab. I sort of prefer it over the "<---->" tabs.
 It is a patch that currently replaces the existing tab mechanism, but IMHO
 this should all be made configurable once the maintainers decide to wake
 up and give me some sort of ok...

 (file #16007)
         Jan Engelhardt <hirogen2>
 Sun 06 Jul 2008 01:24:09 PM UTC, comment #23:

 Patch #4 -- cedit-symbol-prefs.diff

 This patch changes the space fill character to some Unicode dot (·) [this
 one is also available on the text console], and makes the <------> tab
 filler into the Unicode ◀──────▶ too.

 (file #16006)
         Jan Engelhardt <hirogen2>
 Sun 06 Jul 2008 01:21:22 PM UTC, comment #22:

 Patch #3 -- cedit-fix-whitespace.diff

 We definitely need to set MOD_WHITESPACE or the space between tab stops is
 drawn with some random color.

 (file #16005)
         Jan Engelhardt <hirogen2>
 Sun 06 Jul 2008 01:19:54 PM UTC, comment #21:

 Patch #2 -- cedit-eol-mark.diff

 This patch implements comment #8's suggestion to use ¶ as an EOL marker.
 It can be toggled using the Options>Highlight options dialog, or, of
 course, by editing ~/.mc/config directly.

 (file #16004)
         Jan Engelhardt <hirogen2>
 Sun 06 Jul 2008 01:17:43 PM UTC, comment #20:

 Ok since nobody replied here are some patches of my own.
 They require that mc(edit) has COMPLETE support for UTF-8!, which is not
 the case in the mc source distribution. The openSUSE .src.rpm has the
 required utf8 bits. Will try to make them submit theirs.

 Patch #1 -- cedit-configurable-highlight.diff

 This is for comment #19; it allows to switch highlighting. Firstly, it
 adds a dialog (Options > Highlight options) where you can precisely select
 what to highlight

 [ ] Global syntax highlighting

 [ ] Tab highlighting (those <------> markers, which, btw, can get very
 ugly if you have lots of code)

 [ ] Whitespace highlighting (dots at the end-of-line, and, if tab
 highlighting is disabled, anywhere on the line)

 One can already toggle Syntax highlighting with Ctrl-S in mc 4.6.2, for
 the latter two, I added Ctrl-V as a hotkey which cycles through the
 possibilities. My personal preference is to have Tab highlight OFF and
 Whitespace highlight ON.

 (file #16003)
         Jan Engelhardt <hirogen2>
 Fri 29 Feb 2008 07:16:33 PM UTC, comment #19:

 Oh, god... I just updated my Debian box, and I now run MC 4.6.2-pre1 (as
 outputted by mcedit --version). It appears that this patch is included in
 this version of mcedit. I really dislike it. Besides suffering from the
 'cursor disappearing' thingy, I just think its ugly. But that's my humble
 opinion :)
 How can I disable it? The patches attached to this report don't seem to
 make a new configurable parameter available in the configuration dialogs.
         Jurrie Overgoor <leadpumper>
 Tue 04 Sep 2007 05:29:40 AM UTC, comment #18:

 Pavel, I applied your patch to vte-0.16.8. It works.
         Andrew Borodin <a_borodin>
 Mon 03 Sep 2007 01:15:42 PM UTC, comment #17:

 Ok. I tracked the "bug" to vte_terminal_determine_colors() in the vte
 package. To request brighter colors one forces the terminal into "bold
 mode". It seems that in this mode vte allows only the foreground color to
 be bright. In vte's terms a bright color is the same color as the normal
 one but with a special flag set. So what happens is that when the time
 comes for the cursor to blink vte switches the current forground color
 with the current background color and vice versa... As I said above
 both colors are indentified in the same way but one has a special flag,
 however vte uses this flag to brighten the foreground color so at the end
 we end up as if nothing happened. It's hard to say whether this is the
 desired behaviour .. I'll attach a simple patch which changes vte to do
 what seems more logically correct... and I'll open a report in gnome's

 (file #13873)
         Pavel Tsekov <ptsekov>
 Project Administrator
 Fri 31 Aug 2007 04:19:43 PM UTC, comment #16:

 IMO, this must be a bug in gnome-terminal. It doesn't behave properly if
 one uses both the bright and normal colors as the background and
 foreground of the same cell. I changed the
 the definition of "editwhitespace" to "brightred,red" and the cursor is
 not displayed in this case as well. I also changed the color for
 brightblue in my gnome-terminal profile to a different color but no matter
 the cursor wasnt displayed. I'll see if they have a bugreport in their
         Pavel Tsekov <ptsekov>
 Project Administrator
 Fri 31 Aug 2007 09:28:17 AM UTC, comment #15:

 This may be a bug in gnome-terminal as well... I am also using gnome-
 terminal and no matter the color scheme the cursor is invisible. I'll
 investigate further...
         Pavel Tsekov <ptsekov>
 Project Administrator
 Fri 31 Aug 2007 06:07:28 AM UTC, comment #14:

 Oswald, you are right. This effect is depending on terminal emulation
 program and color scheme.

 In linux console, cursor is visible every time. The color of cursor is
 changed to light blue in tab and trailing space positions, but cursor is

 The same is in xterm under X. xterm doesn't have any non-default cursor

 In gnome-terminal and multi-gnome-terminal, which I use, cursor changes
 its color and becomes invisible. ("Green on black" color scheme and "Linux
 console" palette are used in both those programs.)

 Is it possible to make the same cursor color in positions of visualized
 tab an training space as in positions of other symbols?
         Andrew Borodin <a_borodin>
 Thu 30 Aug 2007 12:58:35 PM UTC, comment #13:

 that's weird ... i see no such effect (little surprisingly). though with
 some terminals/color combinations it becomes light blue, too, and thus
 hardly visible, but i don't think we can do much about that.
         Oswald Buddenhagen <ossi>
 Thu 30 Aug 2007 12:39:39 PM UTC, comment #12:

 Yep. As I said - i'll be fixing the patch... I prefer to have it in CVS
 even if it has minor glitches. In the meantime if you find any other
 problems with it - please, feel free to report them.
         Pavel Tsekov <ptsekov>
 Project Administrator
 Thu 30 Aug 2007 12:29:20 PM UTC, comment #11:

 Cursor in TAB and trailing space position is disappeared. This is very
         Andrew Borodin <a_borodin>
 Mon 27 Aug 2007 12:08:04 PM UTC, comment #10:

 The patch is in CVS now. I've commited mcedit-visible-ws-v2.diff with no
 changes whatsoever ... I'll be making changes to it as discussed in this
 bugreport in the next few weeks.
         Pavel Tsekov <ptsekov>
 Project Administrator
 Thu 09 Aug 2007 08:53:35 PM UTC, comment #9:

 i considered making all whitespace visible, but somehow found it pointless
 and even counterproductive for my use cases.
 for linefeeds, i really see no use case ...
 regarding the use of special characters, this is not doable without utter
 hackery. mc is restricted to the abstract char set provided by
 ncurses/slang, which unfortunately does not provide these chars.
         Oswald Buddenhagen <ossi>
 Thu 09 Aug 2007 08:28:12 PM UTC, comment #8:

 This mcedit-visible-ws-v2.diff works great with mc-4.6.1
 What a pity it is not inside mc by default. The light blue color is great
 - it shows invisible characters but not disturbs reading/editing.

 There is one little thing I would like to see:
 make tabs, all spaces and carriage returns visible like in OpenOffice/M$

 This means that:
 -all spaces are visible as dots ···· (unicode 00B7) (not only trailing but
 all - this is comfortable when hunting for double/multi spaces between
 -tabs are visible as arrows → (unicode 2192) (somethhing like -> mc uses
 semigraphics so can draw arrows too)
 -carriage returns are visible as reversed P character ¶ (unicode 00B6)
 (I know this is poor description but just run OO Writer or Word to see how
 these formating characters are marked).

 I really would like to see this patch in mc as default. It is very helpful
 and allows to keep .conf files clean.
         Zbigniew Luszpinski <mr_zbiggy>
 Sun 05 Feb 2006 04:51:56 PM UTC, comment #7:

 it just occurred to me, that i don't want two separate shortcuts for
 toggling these options. two separate persistent options in the config
 dialog are ok, but there should be only one "quick toggle" shortcut
 (ctrl-w) that disables both at once, and is not saved anywhere.
 i suppose the envisioned ctrl-s shortcut for toggling syntax highlighting
 should be non-persistent as well.
         Oswald Buddenhagen <ossi>
 Mon 30 Jan 2006 05:16:22 PM UTC, comment #6:

 Single patch is OK.
         Pavel Tsekov <ptsekov>
 Project Administrator
 Mon 30 Jan 2006 04:33:20 PM UTC, comment #5:

 ok, here's a patch which allows enabling visible trailing whitespace and
 visible tabs independently. i'm not eager to split it into two patches;
 they are too much related.
 i just threw in the options as variables right above the relevant function
 - i'd prefer you wrapping this into proper configurability (options in the
 edit config dialog and keyboard accels) yourself, as i'd have to research
 how to do it first. :}
         Oswald Buddenhagen <ossi>
 Mon 30 Jan 2006 04:19:36 PM UTC, comment #4:

 ok, i changed my mind - i have a strong opinion now. :)
 i think it's right that trailing tabs should not prevent preceeding spaces
 from being marked as trailing: if trailing whitespace removal is
 implemented, all these chars will be equally killed away.
         Oswald Buddenhagen <ossi>
 Mon 30 Jan 2006 03:53:54 PM UTC, comment #3:

 I did try it and have been playing with it for a while. This patch
 adds (1) visible trailing spaces and (2) visible tabs. In fact I prefer to
 think of it as two separate patches. As you suggested on the list it
 should be enhanced so that the user can switch this functionality on and
 off via a fast key. I would add that the user should be allowed to enable
 (1) without enabling (2) and vice versa.
         Pavel Tsekov <ptsekov>
 Project Administrator
 Mon 30 Jan 2006 03:35:14 PM UTC, comment #2:

 well, tabs should stay tabs. masking them away in this special case would
 just lead to surprises.
 not sure about your example. it's true that it looks a bit weird. otoh,
 such whitespace is plainly broken, so it should look broken. :) also, if
 you change it, suddenly chars in the middle of a line will vanish/appear
 if you (append past/remove up to) the trailing tabs. it depends on whether
 one wants to get the static or the dynamic case nicer.
 the patch is really simple, so give it a try. after all, i have no
 particular opinion on this matter - i need to highlight trailing
 whitespace only to annihilate any occurrences of it anyway. :-)=)
         Oswald Buddenhagen <ossi>
 Mon 30 Jan 2006 03:09:00 PM UTC, comment #1:

 How about considering the trailing tabs a trailing whitespace too and
 marking all the traling whitespace with just a dot ?

 Now if a have a like like this:

 int func()<space><space><space><space><tab><tab>

 i get

 int func() <><------><------>

 This is pretty inconsistent and annoying (IMO).
         Pavel Tsekov <ptsekov>
 Project Administrator
 Sat 21 May 2005 07:25:17 PM UTC, original submission:

 visible tabs help putting the tabs where you want them, particularly when
 trying to stay consistent with the style of text written by somebody else.
 making trailing whitespace visible helps avoiding it in undesired places.

 here is a patch that accomplishes this. it is missing an option to disable
 this feature, so i post this as a wish instead of as a patch.

 i wanted the visibility to be as subtle as possible. therefore just
 changing the background color (see leading tabs in Makefile highlite) was
 no option. so i paint tabs as excerpts of <------> and spaces as dots. to
 make it really subtle, i paint it bright blue on dark blue (the regular
 background) - this is hardly visible, unless you are looking for it. i
 know of no way to make it equally subtle on monochrome displays,
 so the feature is disabled alltogether there.
 the whitespace becomes invisible when the text is selected, as there is no
 possibility to merge colors. it'd be nice to fix this generally.
 the highlite color is not defined by syntax highlighting, but by an extra
 palette entry. i think this makes sense.
 this feature overrides other colors that might be defined for whitespace,
 like the red background of tabs in Makefiles. the block in #if 0 would
 preserve the color of already highlighted whitespace, but it's a too broad
 criterion. i don't think ignoring this fact is a problem, as you can
 recognize the tabs anyway (obviously).
 note, that you can't just copy such text from the terminal, as the pseudo-
 whitespace chars will show up in the copy. therefore a hotkey to switch it
 off quickly would be useful. otoh, a) the problem that this feature is
 disabled in selected blocks is an advantage in this context and b) by
 copying, you would be destroying the original whitespace anyway.

Ticket URL: <http://www.midnight-commander.org/ticket/113>
Midnight Commander <www.midnight-commander.org>
Midnight Development Center

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