text: % Generated by roxygen2: do not edit by hand
  % Please edit documentation in R/compute_align.R
  \name{compute_align}
  \alias{compute_align}
  \title{Align positions using length.}
  \usage{
  compute_align(x, var, length = NULL, align = 0.5, dir = "x")
  }
  \arguments{
  \item{x}{Dataset-like object to align. Built-in methods for data frames,
  grouped data frames and ggvis visualisations.}
  
  \item{var}{Name of variable to compute width of.}
  
  \item{length}{An absolute length to use. If \code{NULL} (the default), the
  width will be equivalent to the resolution of the data.}
  
  \item{align}{Where does the existing variable fall on the new bins?
  0 = left edge, 0.5 = center, 1 = right edge.}
  
  \item{dir}{Direction, i.e. \code{"x"} or \code{"y"}. Used to generate
  variable names in output.}
  }
  \value{
  The original data frame, with additional columns:
   \item{'dir'min_}{left boundary of bin}
   \item{'dir'max_}{right boundary of bin}
   \item{'dir'len_}{width of bin}
  }
  \description{
  This compute function is often used in conjunction with
  \code{\link{compute_count}}, when used on data with a continuous x variable.
  By default, the computed width will be equal to the resolution of the data,
  or, in other words the smallest difference between two values in the data.
  }
  \details{
  An absolute width for each x can be specified by using the \code{width}
  argument. If \code{width} is NULL (the default), it will use the resolution
  of the data as the width.
  }
  \examples{
  mtcars \%>\% compute_count(~disp) \%>\% compute_align(~x_)
  mtcars \%>\% compute_count(~mpg) \%>\% compute_align(~x_)
  
  # Use a specific width
  pressure \%>\% compute_count(~temperature) \%>\% compute_align(~x_)
  pressure \%>\% compute_count(~temperature) \%>\% compute_align(~x_, length = 5)
  
  # It doesn't matter whether you transform inside or outside of a vis
  mtcars \%>\% compute_count(~cyl, ~wt) \%>\%
    compute_align(~x_, length = .5) \%>\%
    ggvis(x = ~xmin_, x2 = ~xmax_, y = ~count_, y2 = 0) \%>\%
    layer_rects()
  
  mtcars \%>\%
    ggvis(x = ~xmin_, x2 = ~xmax_, y = ~count_, y2 = 0) \%>\%
    compute_count(~cyl, ~wt) \%>\%
    compute_align(~x_) \%>\%
    layer_rects()
  
  # Varying align
  mtcars \%>\%
    ggvis(x = ~xmin_, x2 = ~xmax_, y = ~count_, y2 = 0) \%>\%
    compute_count(~cyl, ~wt) \%>\%
    compute_align(~x_, length = 0.5, align = input_slider(0, 1)) \%>\%
    layer_rects()
  }
  \seealso{
  \code{\link{compute_bin}} For counting cases within ranges of
    a continuous variable.
  
  \code{\link{compute_count}} For counting cases at specific values
    of a variable.
  }
  