open_measurement_viewport: Open a temporary grid measurement device + viewport.

In eulerr: Area-Proportional Euler and Venn Diagrams with Ellipses

Open a temporary grid measurement device + viewport.

Description

Returns an idempotent closer thunk that pops the viewport and closes the null PDF device. Used so we can call grid::convertWidth(grobWidth(...), "native", ...) at setup time — i.e. before plot.eulergram() ever opens a real device — to size the label boxes that drive label placement.

Usage

open_measurement_viewport(xlim, ylim)

Details

Always opens its own off-screen PDF rather than reusing the caller's active device. Pushing a viewport onto the caller's device adds an entry to its display list, which knitr's plot capture treats as visible change and emits as an extra blank plot before the real plot.eulergram() draws. The off-screen PDF keeps measurement entirely out of the user's display list.

eulerr documentation built on May 30, 2026, 1:07 a.m.