add news about orca()

Author: cpsievert

NEWS.md

@@ -6,6 +6,7 @@
 * Support for **sf** (simple feature) data structures was added to `plot_ly()`, `plot_mapbox()`, and `plot_geo()` (via the new `add_sf()` function). See [this blog post](https://blog.cpsievert.me/2018/03/30/visualizing-geo-spatial-data-with-sf-and-plotly) for an overview.
 * New "special arguments" `stroke`, `strokes`, `alpha_stroke`, `span`, and `spans` were added for easier control over the stroke (i.e., outline) appearance of various (filled) graphical marks. For an overview, see the **sf** blog post linked to in the bullet point above and the new package demos (list all demos with `demo(package = "plotly")`).
 * The new `partial_bundle()` function makes it easy to leverage [partial bundles of plotly.js](https://github.com/plotly/plotly.js#partial-bundles) for reduced file sizes and faster render times.
+* Improved static image exporting via the new `orca()` function (which provides a wrapper around the [orca command-line utility](https://github.com/plotly/orca)). This function does everything `export()` does and more (most notably, adds 'native' svg/pdf export and debugging capabilities), so as a result, the `export()` function is now deprecated.
 * The `config()` function gains a `locale` argument for easily changing localization defaults (see #1270). This makes it possible localize date axes, and in some cases, modebar buttons (see #1270)
 * One may now inform `ggplotly()` about the relevant **shiny** output size via `session$clientData`. This ensures `ggplotly()` sizing is closer to **ggplot2** sizing, even on window resize. For an example, run `plotly_example("shiny", "ggplotly_sizing")`.
 * Instead of an error, `ggplotly(NULL, "message")` and `plotly_build(NULL, "message")` now returns `htmltools::div("message")`, making it easier to relay messages in shiny when data isn't yet ready to plot (see #1116)