MFC r315418,r315480,r316019:

Add teken_256to16() to convert xterm-256 256-color codes to xterm 16-color
codes. This will be used to fix bright colors.

Improve teken_256to8(). Use a lookup table instead of calculations. The
calculations were inaccurate since they used indexes into the xterm-256
6x6x6 color map instead of actual xterm colors. Also, change the threshold
for converting to a primary color: require the primary's component to be
2 or more higher instead of just higher. This affects about 1/5 of the
table entries and gives uniformly distributed colors in the 6x6x6 submap
except for greys (35 entries each for red, green, blue, cyan, brown and
magenta, instead of approx. only 15 each for the mixed colors). Even
more mixed colors would be better for matching colors, but uniform
distribution is best for preserving contrast.

For teken_256to16(), bright colors are just the ones with luminosity >=
60%. These are actually light colors (more white instead of more
saturation), while xterm bright colors except for white itself are
actually saturated with no white, so have luminosity only 50%.

These functions are layering violations. teken cannot do correct
conversions since it shouldn't know the color maps of anything except
xterm. Translating through xterm-16 colors loses information. This
gives bugs like xterm-256 near-brown -> xterm-16 red -> VGA red.

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r315480 | bde | 2017-03-18 11:13:54 +0000 (Sat, 18 Mar 2017) | 51 lines

Fix bright colors for syscons, and make them work for the first time
for vt. Restore syscons' rendering of background (bg) brightness as
foreground (fg) blinking and vice versa, and add rendering of blinking
as background brightness to vt.

Bright/saturated is conflated with light/white in the implementation
and in this description.

Bright colors were broken in all cases, but appeared to work in the
only case shown by "vidcontrol show". A boldness hack was applied
only in 1 layering-violation place (for some syscons sequences) where
it made some cases seem to work but was undone by clearing bold using
ANSI sequences, and more seriously was not undone when setting
ANSI/xterm dark colors so left them bright. Move this hack to drivers.

The boldness hack is only for fg brightness. Restore/add a similar hack
for bg brightness rendered as fg blinking and vice versa. This works
even better for vt, since vt changes the default text mode to give the
more useful bg brightness instead of fg blinking.

The brightness bit in colors was unnecessarily removed by the boldness
hack. In other cases, it was lost later by teken_256to8(). Use
teken_256to16() to not lose it. teken_256to8() was intended to be
used for bg colors to allow finer or bg-specific control for the more
difficult reduction to 8; however, since 16 bg colors actually work
on VGA except in syscons text mode and the conversion isn't subtle
enough to significantly in that mode, teken_256to8() is not used now.

There are still bugs, especially in vidcontrol, if bright/blinking
background colors are set.

Restore XOR logic for bold/bright fg in syscons (don't change OR
logic for vt). Remove broken ifdef on FG_UNDERLINE and its wrong
or missing bit and restore the correct hard-coded bit. FG_UNDERLINE
is only for mono mode which is not really supported.

Restore XOR logic for blinking/bright bg in syscons (in vt, add
OR logic and render as bright bg). Remove related broken ifdef
on BG_BLINKING and its missing bit and restore the correct
hard-coded bit. The same bit means blinking or bright bg depending
on the mode, and we want to ignore the difference everywhere.

Simplify conversions of attributes in syscons. Don't pretend to
support bold fonts. Don't support unusual encodings of brightness.
It is as good as possible to map 16 VGA colors to 16 xterm-16
colors. E.g., VGA brown -> xterm-16 Olive will be converted back
to VGA brown, so we don't need to convert to xterm-256 Brown. Teken
cons25 compatibility code already does the same, and duplicates some
small tables. This is mostly for the sc -> te direction. The other
direction uses teken_256to16() which is too generic.

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r316019 | bde | 2017-03-27 10:48:28 +0000 (Mon, 27 Mar 2017) | 30 lines

Oops, my fix for bright colors broke bright black some more (in cases
that used to work via the bold hack).

Fix the table entry for bright black. Fix spelling of plain black in
nearby table entries (use the macro for black everywhere everywhere).
Fix the currently-unused non-bright color table to not have bright
colors in entries 9-15.

Improve nearby comments. Start converting to the xterm terminology
and default rendering of "bright" instead of "light" for bright
colors.

Syscons wasn't affected by the bug since I optimized it a little by
converting colors 0-15 directly. This also fixes the layering of
the conversion for these colors.

Apply the same optimization to vt (actually the layer above it). This
also moves the conversion 1 closer to the correct layer for colors
0-15.

The optimization of just avoiding 2 calls to a trivial function is worth
about 10% for simple output to the virtual buffer with occasional
rendering. The optimization is so large because the 2 calls are done
on every character, so although there are too many other calls and
other instructions per character, there are only about 10 times as
many. Old versions of syscons were about 10 times faster for simple
output, by using a fast path with about 12 instructions per character.
Rendering to even slow hardware takes relatively little time provided
it is rarely actually done.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Pick UINT_MAX / 100 as an upperbound.

The fix that I applied in r286798 is already good, but it assumes that
sizeof(int) > sizeof(short). Express the upperbound in terms of
UINT_MAX. By dividing that by 100, we're sure that the resulting value
is never larger than approximately UINT_MAX / 10, which is safe.

PR: 202326
Discussed with: kcwu csie org
MFC after: 1 month

Stop parsing digits if the value already exceeds USHRT_MAX.

There is no need for us to support parsing values that are larger than
the maximum terminal window size. In this case that would be the maximum
of unsigned short.

The problem with parsing larger values is that they can cause integer
overflows when adjusting the cursor position, leading to all sorts of
failing assertions.

PR: 202326
Reported by: kcwu csie org
MFC after: 1 month

Fix typo.

Pointed by: Ronald Klop
Pointy hat: ray

Sponsored by: The FreeBSD Foundation

Fix crash on load of bigger font. It reduce width and height of terminal, but
current cursor position stay bigger that terminal window size, so next input
triggers assert.

Reported by: emaste

Sponsored by: The FreeBSD Foundation

Merge VT(9) project (a.k.a. newcons).

Reviewed by: nwhitehorn
MFC_to_10_after: re approval

Sponsored by: The FreeBSD Foundation

Fix various whitespace inconsistencies in sys/teken.

Add proper build infrastructure for teken.

I'm not sure whether we should install teken as a library on any stock
FreeBSD installation, but I can imagine people want to tinker around
with it now and then. Create a /sys/teken/libteken, which holds a
Makefile to install a shared library version of the terminal emulator,
complete with a manpage.

Also add Makefiles for the demo/stress applications, to build it against
the shared library.

Just use <stdint.h> instead of <inttypes.h>. We don't need it here.

Place home and end before insert and delete.

These keys have different sequences when using cursorkeys, while insert
and delete stay the same. If they are placed like this, libteken will
return NULL instead of a proper sequence for these characters.

Allow Syscons terminal emulators to provide function key strings.

xterm and cons25 have some incompatibilities when it comes to escape
sequences for special keys, such as F1 to F12, home, end, etc. Add a new
te_fkeystr() that can be used to override the strings.

scterm-sck won't do anything with this, but scterm-teken will use
teken_get_sequences() to obtain the proper sequence.

Discard Device Control Strings and Operating System Commands.

These strings often contain things like:

- Window titles.
- Extended key map functionality.
- Color palette switching.

We could look at these features in the future (if people consider them
to be important enough), but we'd better discard them now. This fixes
some artifacts people reported when using TERM=xterm.

Reported by: des@, Paul B. Mahol

Add 256 color support.

It is quite inconvenient that if an application for xterm uses 256 color
mode, text suddenly starts to blink (because of ;5; in the middle).
We'd better just implement 256 color mode and add a conversion routine
from 256 to 8 color mode, which doesn't seem to be too bad in practice.

Remapping colors is done quite simple. If one of the channels is most
actively represented, primary colors are used. If two channels are most
actively represented, secondary colors are used. If all three channels
are equal (gray), it picks between black and white.

Reported by: Paul B. Mahol <onemda gmail com>

Get rid of now deprecated SCS wrappers.

We always build SCS, even when processing 8-bit data. There is no reason
why we should be able to disable it now.

Make SCS work in 8-bit mode.

This means we can finally do things like VT100 box drawing when using
Syscons (8-bit characters). As far as I know, the only remaining issue
is the absense of proper escape sequences for special keyboard
characters (cursor, F1 to F12, etc) and xterm emulation should be ready
for general use.

Enabling xterm would have the following advantages:

- Easier possible migration to Unicode. cons25 termcap entries are very
8-bit centric. They use things like CP437 characters for box drawing,
etc.

- Better support for SSH'ing to other operating systems/devices. Most
switches use VT100-style admin interfaces.

- Reduced bandwidth, because applications can now use things like
scrolling regions.

- You can finally use applications like dtach(1) on both the console and
inside an xterm.

Commit all local modifications I have to libteken:

- Make xterm/cons25 support runtime configurable. This allows me to
share libteken between syscons and my new vt driver.
- Add a fix to print blanks after printing a double width character to
prevent rendering artifacts.
- Add some more utility functions that I use in the vt driver.

Small style(9) bug introduced in the previous commit.

Make 8-bit support run-time configurable.

Now to do the same for xterm support. This means people can eventually
toy around with xterm+UTF-8 without recompiling their kernel.

Make resizing of teken terminals a bit more safe.

Just perform a full reset when resizing the terminal. This means the
cursor, scrolling region, etc. are never positioned outside the
terminal.

Expose the TF_REVERSE flag to the console driver.

Right now libteken processes TF_REVERSE internally and returns the
toggled colors to the console driver. This isn't entirely correct. This
means that the bold flag is always processed by the foreground color,
while reversing should be done after the foreground color has been set
to a brighter version by the bold flag.

This is no problem with the syscons driver, because with VGA it only
supports 16 foreground and 8 background colors. My WIP console driver
reconfigures the graphics hardware to disable the blink functionality
and uses 16 foreground and 16 background colors. This means that this
driver will handle the TF_REVERSE flag a little different from what
syscons does right now.

Move libteken out of the syscons directory.

I initially committed libteken to sys/dev/syscons/teken, but now that
I'm working on a console driver myself, I noticed this was not a good
decision. Move it to sys/teken to make it easier for other drivers to
use a terminal emulator.

Also list teken.c in sys/conf/files, instead of listing it in all the
files.arch files separately.

Small fixes to Unicode handling:

- Add more mappings for Greek characters and the Euro sign.
- Print UTF-8 characters in the log file as hexadecimal.

Restore support for bell pitch/duration.

Because we only support a single argument to tf_param, use 16 bits for
the pitch and 16 bits for the duration. While there, make the argument
unsigned. There isn't a single param call that needs a signed integer.

Submitted by: danfe (modified)

Just use default behaviour on tabstops when using too many columns.

It seems I didn't fix this issue before committing teken to the tree. My
initial idea was to somehow add an error mechanism to instruct the video
driver author to increase T_NUMCOL when using very big terminals. It
turns out we have platforms where we have gigantic consoles on systems
like the Apple PowerMac G5, which means we crash there right now.

Just ignore tabstops placed beyond column 160. Just force tabs to be
placed on each 8 columns.

Reported by: nwhitehorn

Make a 1:1 mapping between syscons stats and terminal emulators.

After I imported libteken into the source tree, I noticed syscons didn't
store the cursor position inside the terminal emulator, but inside the
virtual terminal stat. This is not very useful, because when you
implement more complex forms of line wrapping, you need to keep track of
more state than just the cursor position.

Because the kernel messages didn't share the same terminal emulator as
ttyv0, this caused a lot of strange things, like kernel messages being
misplaced and a missing notification to resize the terminal emulator for
kernel messages never to be resized when using vidcontrol.

This patch just removes kernel_console_ts and adds a special parameter
to te_puts to determine whether messages should be printed using regular
colors or the ones for kernel messages.

Reported by: ache
Tested by: nyan, garga (older version)

Properly implement GIO_ATTR and CONS_GETINFO.

It seems I didn't implement these two ioctl()'s properly, which meant
vidcontrol couldn't properly obtain certain terminal parameters.

Properly implement the VT100 SCS sequences in xterm-mode.

Even though VT100-like devices can display non-ASCII characters, they do
not use an 8-bit character set. Special escape sequences allow the VT100
to switch character maps. The special graphics character set stores the
box drawing characters, starting at 0x60, ending at 0x7e. This means
we now pass the character map tests in vttest, even the save/restore
cursor test, combined with character maps. dialog(1) also works a lot
better now.

This commit also includes some other minor fixes:

- Default to 24 lines in teken_demo when using xterm emulation.
- Make white foreground and background work in teken_demo.

Allow experimental libteken features to be tested without changing code.

The teken library already supports UTF-8 handling and xterm emulation,
but we have reasons to disable this right now. Because we should make it
easy and interesting for people to experiment with these features, allow
them to be set in kernel configuration files.

Before this commit we had a flag called `TEKEN_CONS25' to enable
cons25-style emulation. I'm calling it the opposite now, `TEKEN_XTERM',
because we want to enable it in kernel configuration files explicitly.

Requested by: kib

Import yet some more small fixes to libteken sources:

- Implement NP (ASCII 12, Form Feed). When used with cons25, it should
clear the screen and place the cursor at the top of the screen. When
used with xterm, it should just simulate a newline.

- When we want to use xterm emulation, make teken_demo set TERM to
xterm.

Spotted by: Paul B. Mahol <onemda@gmail.com>

Print control characters, even though they are normally not visible.

With cons25, there are printable characters below 0x1B. This is not the
case with ASCII, UTF-8, etc. but in this case we just have to.

Also don't set LC_CTYPE to UTF-8 when libteken is compiled without UTF-8
in the demo-application.

Resolve some regressions related to tabs and linewrap handling.

It turns out I was looking too much at mimicing xterm, that I didn't
take the differences of cons25 into account. There are some differences
between xterm and cons25 that are important. Create a new #define called
TEKEN_CONS25 that can be toggled to switch between cons25 and xterm
mode.

- Don't forget to redraw the cursor after processing a forward/backward
tabulation.

- Implement cons25-style (WYSE?) autowrapping. This form of autowrapping
isn't that nice. It wraps the cursor when printing something on column
80. xterm wraps when printing the first character that doesn't fit.

- In cons25, a \t shouldn't overwrite previous contents, while xterm
does.

Reported by: Garrett Cooper <yanefbsd gmail com>

Replace syscons terminal renderer by a new renderer that uses libteken.

Some time ago I started working on a library called libteken, which is
terminal emulator. It does not buffer any screen contents, but only
keeps terminal state, such as cursor position, attributes, etc. It
should implement all escape sequences that are implemented by the
cons25 terminal emulator, but also a fair amount of sequences that are
present in VT100 and xterm.

A lot of random notes, which could be of interest to users/developers:

- Even though I'm leaving the terminal type set to `cons25', users can
do experiments with placing `xterm-color' in /etc/ttys. Because we
only implement a subset of features of xterm, this may cause
artifacts. We should consider extending libteken, because in my
opinion xterm is the way to go. Some missing features:

- Keypad application mode (DECKPAM)
- Character sets (SCS)

- libteken is filled with a fair amount of assertions, but unfortunately
we cannot go into the debugger anymore if we fail them. I've done
development of this library almost entirely in userspace. In
sys/dev/syscons/teken there are two applications that can be helpful
when debugging the code:

- teken_demo: a terminal emulator that can be started from a regular
xterm that emulates a terminal using libteken. This application can
be very useful to debug any rendering issues.

- teken_stress: a stress testing application that emulates random
terminal output. libteken has literally survived multiple terabytes
of random input.

- libteken also includes support for UTF-8, but unfortunately our input
layer and font renderer don't support this. If users want to
experiment with UTF-8 support, they can enable `TEKEN_UTF8' in
teken.h. If you recompile your kernel or the teken_demo application,
you can hold some nice experiments.

- I've left PC98 the way it is right now. The PC98 platform has a custom
syscons renderer, which supports some form of localised input. Maybe
we should port PC98 to libteken by the time syscons supports UTF-8?

- I've removed the `dumb' terminal emulator. It has been broken for
years. It hasn't survived the `struct proc' -> `struct thread'
conversion.

- To prevent confusion among people that want to hack on libteken:
unlike syscons, the state machines that parse the escape sequences are
machine generated. This means that if you want to add new escape
sequences, you have to add an entry to the `sequences' file. This will
cause new entries to be added to `teken_state.h'.

- Any rendering artifacts that didn't occur prior to this commit are by
accident. They should be reported to me, so I can fix them.

Discussed on: current@, hackers@
Discussed with: philip (at 25C3)