A text as one string with interpolation (spec/14 §7.1): "Uptime for #{var(:host)}".
A :text — a label's text, a legend's title, meta.name, meta.description — is
a string in which #{var(:name)} stands for a variable and #{field(:name)} for a
datum's field (a mark's label reads one per element, §5.5). A literal #{ is written
\#{. parse/1 reads the string into its parts and unparse/1 writes parts back;
the two are inverse, and a list of parts — the form an earlier version wrote — is
what unparse/1 takes, which is the migration (§9).
iex> Visualize.Chart.Text.parse("Uptime for \#{var(:host)} over 24h")
{:ok, ["Uptime for ", %Visualize.Chart.Var{name: :host}, " over 24h"]}
iex> Visualize.Chart.Text.parse("cost \\\#{literal}")
{:ok, ["cost \#{literal}"]}
iex> Visualize.Chart.Text.unparse(["u: ", %Visualize.Chart.Var{name: :unit}])
"u: \#{var(:unit)}"
iex> Visualize.Chart.Text.parse("open \#{var(:x")
{:error, :unterminated}Summary
Functions
Parts as lines: the parts split at every newline in a string part; [[]] for an empty
text (spec/14 §7.1).
The parts of a text. A list is already parts and is returned as it is; a string is
read, and an unterminated #{ or a hole that names neither a variable nor a field is
an error.
The parts of a text, raising on one that does not read — for a text already validated.
Whether a string carries a hole, so a plain string can be told from a template at a glance.
The string form of parts: a variable as #{var(:name)}, a field as #{field(:name)},
a literal #{ escaped. A string is returned as it is.
The estimated width of a text at a font size: 0.6 × the font size per character
(spec/14 §5.5). It is the one estimate the library makes of a text's width — the
legend's layout and a mark label's fit read it — and it is public so a design can
size itself by it, as a ring leaves room for the labels outside it (#489). A design
cannot measure a glyph, so it is an estimate: a wide glyph runs over it.
Types
@type part() :: String.t() | Visualize.Chart.Var.t() | {:field, atom()}
One part of a text: a string, a variable, or a datum's field.
Functions
Parts as lines: the parts split at every newline in a string part; [[]] for an empty
text (spec/14 §7.1).
iex> Visualize.Chart.Text.lines(["Uptime\n24 h ", %Visualize.Chart.Var{name: :unit}])
[["Uptime"], ["24 h ", %Visualize.Chart.Var{name: :unit}]]
iex> Visualize.Chart.Text.lines(["one line"])
[["one line"]]
iex> Visualize.Chart.Text.lines([])
[[]]@spec parse(String.t() | [part()]) :: {:ok, [part()]} | {:error, :unterminated | {:hole, String.t()}}
The parts of a text. A list is already parts and is returned as it is; a string is
read, and an unterminated #{ or a hole that names neither a variable nor a field is
an error.
The parts of a text, raising on one that does not read — for a text already validated.
Whether a string carries a hole, so a plain string can be told from a template at a glance.
The string form of parts: a variable as #{var(:name)}, a field as #{field(:name)},
a literal #{ escaped. A string is returned as it is.
The estimated width of a text at a font size: 0.6 × the font size per character
(spec/14 §5.5). It is the one estimate the library makes of a text's width — the
legend's layout and a mark label's fit read it — and it is public so a design can
size itself by it, as a ring leaves room for the labels outside it (#489). A design
cannot measure a glyph, so it is an estimate: a wide glyph runs over it.
iex> Visualize.Chart.Text.width("Wednesday", 11)
59.4
iex> Visualize.Chart.Text.width("", 11)
0.0