6.2.1Linear Ticks🔗 i

To lay out ticks, linear-ticks-layout finds the power of base closest to the axis interval size, chooses a simple first tick, and then chooses a skip length using divisors that maximizes the number of ticks without exceeding number. For strategic use of non-default arguments, see bit/byte-ticks , currency-ticks , and fraction-ticks . The default arguments correspond to the standard 1-2-5-in-base-10 rule used almost everywhere in plot tick layout.

To format ticks, linear-ticks-format uses real->plot-label passing the value of scientific?, and uses digits-for-range to determine the maximum number of fractional digits in the decimal expansion.

Changed in version 1.1 of package plot-gui-lib: Added the #:scientific? argument to linear-ticks-format and linear-ticks .

6.2.2Log Ticks🔗 i

The #:base keyword argument is the logarithm base. The #:scientific keyword argument disables scientific formatting, similarly to linear-ticks . See plot-z-far-ticks for an example of use.

6.2.3Date Ticks🔗 i

These axis ticks regard values as being in seconds since a system-dependent Universal Coordinated Time (UTC) epoch. (For example, the Unix and Mac OS X epoch is January 1, 1970 UTC, and the Windows epoch is January 1, 1601 UTC.) Use date->seconds to convert local dates to seconds, or datetime->real to convert dates to UTC seconds in a way that accounts for time zone offsets.

Actually, date-ticks-layout does not always space ticks quite uniformly. For example, it rounds ticks that are spaced about one month apart or more to the nearest month. Generally, date-ticks-layout tries to place ticks at minute, hour, day, week, month and year boundaries, as well as common multiples such as 90 days or 6 months.

To try to avoid displaying overlapping labels, date-ticks-format chooses date formats from formats for which labels will contain no redundant information.

All the format specifiers given in srfi/19 (which are derived from Unix’s date command), except those that represent time zones, are allowed in date format strings.

value

24h-descending-date-ticks-formats :(listof string? )

=

'("~Y-~m-~d ~H:~M:~f"

"~Y-~m-~d ~H:~M"

"~Y-~m-~d ~Hh"

"~Y-~m-~d"

"~Y-~m"

"~Y"

"~m-~d ~H:~M:~f"

"~m-~d ~H:~M"

"~m-~d ~Hh"

"~m-~d"

"~H:~M:~f"

"~H:~M"

"~Hh"

"~M:~fs"

"~Mm"

"~fs")

value

12h-descending-date-ticks-formats :(listof string? )

=

'("~Y-~m-~d ~I:~M:~f ~p"

"~Y-~m-~d ~I:~M ~p"

"~Y-~m-~d ~I ~p"

"~Y-~m-~d"

"~Y-~m"

"~Y"

"~m-~d ~I:~M:~f ~p"

"~m-~d ~I:~M ~p"

"~m-~d ~I ~p"

"~m-~d"

"~I:~M:~f ~p"

"~I:~M ~p"

"~I ~p"

"~M:~fs"

"~Mm"

"~fs")

6.2.4Time Ticks🔗 i

These axis ticks regard values as being in seconds. Use datetime->real to convert sql-time or plot-time values to seconds.

Generally, time-ticks-layout tries to place ticks at minute, hour and day boundaries, as well as common multiples such as 12 hours or 30 days.

To try to avoid displaying overlapping labels, time-ticks-format chooses a date format from formats for which labels will contain no redundant information.

All the time-related format specifiers given in srfi/19 (which are derived from Unix’s date command) are allowed in time format strings.

value

24h-descending-time-ticks-formats :(listof string? )

=

'("~dd ~H:~M:~f"

"~dd ~H:~M"

"~dd ~Hh"

"~dd"

"~H:~M:~f"

"~H:~M"

"~Hh"

"~M:~fs"

"~Mm"

"~fs")

value

12h-descending-time-ticks-formats :(listof string? )

=

'("~dd ~I:~M:~f ~p"

"~dd ~I:~M ~p"

"~dd ~I ~p"

"~dd"

"~I:~M:~f ~p"

"~I:~M ~p"

"~I ~p"

"~M:~fs"

"~Mm"

"~fs")

6.2.5Currency Ticks🔗 i

The #:kind keyword argument is either a string containing the currency symbol, or a currency code such as 'USD, 'GBP or 'EUR. The currency-ticks-format function can map most ISO 4217 currency codes to their corresponding currency symbol.

The #:scales keyword argument is a list of suffixes for each 103 scale, such as "K" (US thousand, or kilo), "bn" (UK short-scale billion) or "Md" (EU long-scale milliard). Off-scale amounts are given power-of-ten suffixes such as “×1021.”

Cultural sensitivity notwithstanding, when writing for a local audience, it is generally considered proper to use local currency scales and formats for foreign currencies, but use the foreign currency symbol.

The abbreviations actually used vary with geography, even within countries, but these seem to be common. Further long-scale suffix abbreviations such as for “billiard” are omitted due to lack of even weak consensus.

6.2.6Other Ticks🔗 i

The #:kind keyword argument indicates either International System of Units ('SI) suffixes, as used to communicate hard drive capacities, or Computer Science ('CS) suffixes, as used to communicate memory capacities.

6.2.7Tick Combinators🔗 i

6.2.8Tick Data Types and Contracts🔗 i

Note that the layout function returns pre-tick s, or unlabeled ticks, and a separate format function is used to produce the labels for the ticks.

The returned labels should be usually distinct, as the plot library will consider ticks with labels that are string=? to be duplicates and collapse them, however, this feature can be used by a custom format function to force removal of some ticks from the plot.

Axis bounds can be used to determine how many decimal digits to display, usually by applying digits-for-range to the bounds.