Release CHANGES IN knitr VERSION 1.9 · yihui/knitr

NEW FEATURES

added a new function load_cache() so that we can read an object from a cached code chunk, even if the chunk appears later in the document and the object needs to be used earlier; see the example #114 at https://github.com/yihui/knitr-examples (related to #868)
added a new function clean_cache() to clean up the cache files that are probably no longer needed, e.g. after you rename or delete cached code chunks (thanks, @sjmgarnier, #933)
knit2wp() can update an existing post or create a page now (thanks, @jaredlander, #916, #917)
added an engine stan to support Stan through the rstan package; see http://rpubs.com/jrnold/knitr-stan for an example (thanks, @jrnold, #903)
for the tikz engine, the path to the convert utility of ImageMagick can be specified via the chunk option engine.opts, e.g. engine.opts = list(convert = 'path/to/convert') (thanks, @mienkoja, #897)
similarly, more command line arguments to convert can be specified via, for example, engine.opts = list(convert.opts = '-density 300') (#896)

when the chunk option dev = 'png', grDevices::png() is used to record plots, instead of the default PDF null device (thanks, @yixuan, #729)
currently R (3.1.2) does not really pass the vignette encoding to vignette engines (which is probably a bug), and knitr vignette engines will assume UTF-8 is the file encoding
when the chunk option tidy=FALSE, and eval takes a numeric vector, it used to mean the line numbers of the code chunk; now it means the indices of the R expressions in the code chunk, regardless of tidy=FALSE or TRUE (yihui/knitr-examples#39, thanks, @isomorphisms)

you need to upgrade the rgl package to at least v0.95.1201 if you use the hook function hook_webgl() (thanks, @dmurdoch, #901)
for the automatically generated figure caption and label of a figure, the label is placed outside of the caption now, i.e. the format was changed from \caption{\label{}} to \caption{}\label{} (thanks, @dr-moebius, @krlmlr, @ltorgo, #746)

fixed #898: kable() did not work on matrices with duplicate row names (thanks, @tomaskrehlik)
fixed #927: kable() did not work for matrices of zero row and/or zero column (thanks, @hadley)
fixed #929: opts_knit$restore() does not restore the animation.fun option (thanks, @julian-gehring)