savePNG {animation}R Documentation

Save PNG image from the current graphical device

Description

Copy the current graphical device to a PNG device to generate a PNG image file.

Usage

savePNG(outdir = tempdir(), n = 1, width = 480, height = 480, ...)

Arguments

outdir physical directory to store the PNG image (default in the temporary directory)
n file name of the PNG image; can be either numeric or characters
width width of PNG image
height height of PNG image
... other parameter passed to png

Details

Actually for Windows users, savePNG is almost identical to savePlot(type = "png"). However, there's no savePlot for Linux users, so this special funtion just acts as a wrapper for saving plots. The work behind this function is just to copy the plot in the current graphical device to a png device using dev.copy.

To make animations, we need to specify the argument n as a sequence of integers so that we can ultimately get a series of image files named ‘1.png’, ‘2.png’, ... Thus the JavaScript in the HTML animation page will be able to find these image frames. Check the souce code of any animation functions to understand this approach.

Value

None (invisible `NULL').

Note

This function provides a general method to save plots as PNG files, thus ani.start does not need to be called beforehand unless you want to make animations.

Author(s)

Yihui Xie

See Also

ani.start, ani.stop

Examples

## Not run: 
 
# a plot save to file.path(getwd(), "1.png") 
plot(rnorm(100)) 
savePNG(getwd(), n = 1)

# a sequence of plots saved in the work directory 
# this is just how animations are produced 
for(i in 1:10){
  plot(rnorm(1), rnorm(1), xlim = c(-1, 1), ylim = c(-1, 1))
  savePNG(getwd(), n = i) 
}
# you might need file.remove(paste(1:10, ".png", sep = "")) 
## End(Not run)


[Package animation version 0.2-0 Index]