Cairo (version 1.6-2)

Cairo.onSave: Cairo callbacks

Description

Cairo.onSave set the onSave callback which allows R code to be run when Cairo finalizes a page (either due to a new page being created or by the device being closed). The callback expects function(device, page) where device will be the device number and page is the currently finished page number (starting at 1).

Usage

Cairo.onSave(device = dev.cur(), onSave)

Value

The old callback being replaced or NULL if there was none.

Arguments

device

device number or Cairo object (as returned by the Cairo function)

onSave

function that will replace the current callback or NULL to remove the current callback

Author

Simon Urbanek

See Also

Cairo

Examples

if (require(png, quietly=TRUE)) {
  dev <- Cairo(800, 600, type='raster')
  Cairo.onSave(dev, function(dev, page)
    .GlobalEnv$png <- writePNG(Cairo.capture(dev))
  )
  plot(1:10, col=2)
  dev.off()
  str(png)
}