R: Hold or Flush Output on an On-Screen Graphics Device.

dev.flush {grDevices} | R Documentation

## Hold or Flush Output on an On-Screen Graphics Device.

### Description

This gives a way to hold/flush output on certain on-screen devices, and is ignored by other devices.

### Usage

    dev.hold(level = 1L)
    dev.flush(level = 1L)

### Arguments

`level` | Integer >= 0. The amount by which to change the hold level. Negative values will be silently replaced by zero.

### Details

Devices which implement this maintain a stack of hold levels: calling `dev.hold` increases the level and `dev.flush` decreases it. Calling `dev.hold` when the hold level is zero increases the hold level and inhibits graphics display. When calling `dev.flush` clears all pending holds the screen display is refreshed and normal operation is resumed.

This is implemented for the cairo-based `X11` types with buffering. When the hold level is positive the ‘watch’ cursor is set on the device's window.

It is available on the `quartz` device on macOS.

This is implemented for the `windows` device with buffering selected (the default). When the hold level is positive the ‘busy’ cursor is set on the device's window.

### Value

The current level after the change, invisibly. This is `0` on devices where hold levels are not supported.

[Package grDevices version 3.5.1 Index]