First implementation of plotCache

man/plotCache.Rd

@@ -0,0 +1,53 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/render-plot.R
+\name{plotCache}
+\alias{plotCache}
+\title{Disk-based plot cache}
+\usage{
+plotCache(cacheId, invalidationExpr, width, height, res = 72, plotFunc,
+  cachePath = file.path(tempdir(), cacheId),
+  invalidation.env = parent.frame(), invalidation.quoted = FALSE)
+}
+\arguments{
+\item{cacheId}{An identifier for this cache; by default, will be incorporated
+into the cache directory path.}
+
+\item{invalidationExpr}{Any expression or block of code that accesses any
+reactives whose invalidation should cause cache invalidation. This
+typically would be an expression that indicates that the source data has
+changed. Use \code{NULL} if you don't want to cause cache invalidation.}
+
+\item{width, height}{The dimensions of the plot. (Use double the user
+width/height for retina/hi-dpi compatibility.)}
+
+\item{res}{The resolution of the PNG. Use 72 for normal screens, 144 for
+retina/hi-dpi.}
+
+\item{plotFunc}{Plotting logic, provided as a function that takes zero or
+more arguments. Don't worry about setting up a graphics device or creating
+a PNG; just write to the graphics device (you must call \code{print()} on
+ggplot2 objects).}
+
+\item{cachePath}{The location on disk where the cache will be stored. By
+default, uses a temp directory, which is generally cleaned up during a
+normal shutdown of the R process.}
+
+\item{invalidation.env}{The environment where the \code{invalidationExpr} is
+evaluated.}
+
+\item{invalidation.quoted}{Is \code{invalidationExpr} expression quoted? By
+default, this is FALSE. This is useful when you want to use an expression
+that is stored in a variable; to do so, it must be quoted with
+\code{quote()}.}
+}
+\description{
+Creates a read-through cache for plots. The plotting logic is provided as
+plotFunc, a function that can have any number/combination of arguments; the
+return value of plotCache is a function that should be used in the place of
+plotFunc. Each unique combination of inputs will be cached to disk in the
+location specified by cachePath.
+}
+\details{
+The invalidationExpr expression will be monitored and whenever it is
+invalidated, so too is the cache invalidated (the contents are erased).
+}