error with loop=FALSE option

[cainesap]

Taking the example from the README, which I can reproduce without issue, and adding what I think is the correct library (library(animate)) and options calls (ani.options(loop = FALSE)):

library(gapminder)
library(ggplot2)
library(gganimate)
library(animate)
theme_set(theme_bw())
ani.options(loop = FALSE)
p <- ggplot(gapminder, aes(gdpPercap, lifeExp, size = pop, color = continent, frame = year)) +
  geom_point() +
  scale_x_log10()
gg_animate(p)

I encounter the following error:

Executing: 
'convert' -loop FALSE -delay 100 Rplot1.png Rplot2.png Rplot3.png
    Rplot4.png Rplot5.png Rplot6.png Rplot7.png Rplot8.png Rplot9.png
    Rplot10.png Rplot11.png Rplot12.png 'filef899fc930d.gif'
convert: invalid argument for option `-loop': FALSE @ error/convert.c/ConvertImageCommand/2024.
an error occurred in the conversion... see Notes in ?im.convert
Error in file(file, "rb") : cannot open the connection
In addition: Warning messages:
1: In normalizePath(movie.name) :
  path[1]="filef899fc930d.gif": No such file or directory
2: In file(file, "rb") :
  cannot open file '/var/folders/p8/8d4g5v_53t3glcsclzx5cc8h0000gn/T//RtmptnzNkU/gganimate/filef899fc930d.gif': No such file or directory

[Running R 3.3.1 "Bug in your hair" on Mac OS X 10.11.6]

[ottlngr]

Is there a workaround for this issue?

[ottlngr]

To solve this and to disable looping, one has to set loop = 1 in ani.options(), so that -loop 1 is forwarded to ImageMagick. From the ImageMagick manual:

-loop {number}:Number of times the GIF animation is to cycle though the image sequence before stopping.

So this is actually not an issue with gganimate but rather with the animation package, which provides ani.options().

[ottlngr]

yihui/animation#90

[pearsonca]

This issue should be resurrected - all renderers default to loop=TRUE. If I define and use

altrenderer <- gifski_renderer(loop=FALSE)
anim_save(...etc..., renderer=altrenderer)

then I can get the desired result, but the conversation here all points towards using ani.options(loop=TRUE) to manage this.

One simple approach to this would be to have loop=TRUE in the signature in anim_save and then have the default renderer construction use the value of loop.

At the very least it's a documentation issue.

[thomasp85]

This issue is related to the old API and has no bearing on the new version.

[pearsonca]

Fair enough; what is the "right" way to do it in the new API?

[thomasp85]

Do it in the renderer as you are doing already. Not all types of output can be looped so it does not make sense to have an argument in animate()