state_at_end | R Documentation |
state_at_end
reads through strings computing the accumulated SGR and
OSC hyperlinks, and outputs the active state at the end of them.
close_state
produces the sequence that closes any SGR active and OSC
hyperlinks at the end of each input string. If normalize = FALSE
(default), it will emit the reset code "ESC[0m" if any SGR is present.
It is more interesting for closing SGRs if normalize = TRUE
. Unlike
state_at_end
and other functions close_state
has no concept of carry
:
it will only emit closing sequences for states explicitly active at the end
of a string.
state_at_end(
x,
warn = getOption("fansi.warn", TRUE),
term.cap = getOption("fansi.term.cap", dflt_term_cap()),
normalize = getOption("fansi.normalize", FALSE),
carry = getOption("fansi.carry", FALSE)
)
close_state(
x,
warn = getOption("fansi.warn", TRUE),
normalize = getOption("fansi.normalize", FALSE)
)
x |
a character vector or object that can be coerced to such. |
warn |
TRUE (default) or FALSE, whether to warn when potentially
problematic Control Sequences are encountered. These could cause the
assumptions |
term.cap |
character a vector of the capabilities of the terminal, can
be any combination of "bright" (SGR codes 90-97, 100-107), "256" (SGR codes
starting with "38;5" or "48;5"), "truecolor" (SGR codes starting with
"38;2" or "48;2"), and "all". "all" behaves as it does for the |
normalize |
TRUE or FALSE (default) whether SGR sequence should be
normalized out such that there is one distinct sequence for each SGR code.
normalized strings will occupy more space (e.g. "\033[31;42m" becomes
"\033[31m\033[42m"), but will work better with code that assumes each SGR
code will be in its own escape as |
carry |
TRUE, FALSE (default), or a scalar string, controls whether to
interpret the character vector as a "single document" (TRUE or string) or
as independent elements (FALSE). In "single document" mode, active state
at the end of an input element is considered active at the beginning of the
next vector element, simulating what happens with a document with active
state at the end of a line. If FALSE each vector element is interpreted as
if there were no active state when it begins. If character, then the
active state at the end of the |
character vector same length as x
.
Control Sequences are non-printing characters or sequences of characters.
Special Sequences are a subset of the Control Sequences, and include CSI
SGR sequences which can be used to change rendered appearance of text, and
OSC hyperlinks. See fansi
for details.
Several factors could affect the exact output produced by fansi
functions across versions of fansi
, R
, and/or across systems.
In general it is best not to rely on exact fansi
output, e.g. by
embedding it in tests.
Width and grapheme calculations depend on locale, Unicode database
version, and grapheme processing logic (which is still in development), among
other things. For the most part fansi
(currently) uses the internals of
base::nchar(type='width')
, but there are exceptions and this may change in
the future.
How a particular display format is encoded in Control Sequences is
not guaranteed to be stable across fansi
versions. Additionally, which
Special Sequences are re-encoded vs transcribed untouched may change.
In general we will strive to keep the rendered appearance stable.
To maximize the odds of getting stable output set normalize_state
to
TRUE
and type
to "chars"
in functions that allow it, and
set term.cap
to a specific set of capabilities.
?fansi
for details on how Control Sequences are
interpreted, particularly if you are getting unexpected results,
unhandled_ctl
for detecting bad control sequences.
x <- c("\033[44mhello", "\033[33mworld")
state_at_end(x)
state_at_end(x, carry=TRUE)
(close <- close_state(state_at_end(x, carry=TRUE), normalize=TRUE))
writeLines(paste0(x, close, " no style"))
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