A few helper functions for the formatStyle() function to
calculate CSS styles for table cells based on the cell values. Under the
hood, they just generate JavaScript and CSS code from the values specified in
R.
styleInterval(cuts, values)styleEqual(levels, values)
styleColorBar(data, color, angle = 90)
a vector of cut points (sorted increasingly)
a vector of CSS values
a character vector of data values to be mapped (one-to-one) to CSS values
a numeric vector whose range will be used for scaling the table data from 0-100 before being represented as color bars. A vector of length 2 is acceptable here for specifying a range possibly wider or narrower than the range of the table data itself.
the color of the bars
a number of degrees representing the direction to fill the gradient relative to a horizontal line and the gradient line, going counter-clockwise. For example, 90 fills right to left and -90 fills left to right.
The function styleInterval() maps intervals to CSS values. Its
argument values must be of length n + 1 where n =
length(cuts). The right-closed interval (cuts[i - 1], cuts[i]] is
mapped to values[i] for i = 2, 3, ..., n; values[1] is
for the interval (-Inf, cuts[1]], and values[n + 1] is for
(cuts[n], +Inf). You can think of the order of cuts and
values using this diagram: -Inf -> values[1] -> cuts[1] ->
values[2] -> cuts[2] -> ... -> values[n] -> cuts[n] -> values[n + 1] ->
+Inf.
The function styleEqual() maps data values to CSS values in the
one-to-one manner, i.e. values[i] is used when the table cell value is
levels[i].
The function styleColorBar() can be used to draw background color bars
behind table cells in a column, and the width of bars is proportional to the
column values.