add strokewidth parameter to image_annotate

[retowyss]

Adding missing strokewidth parameter to image_annotate.

library(magick)

img <- image_blank(480, 320)

image_annotate(img, "Strokewidth Test", size = 60, strokecolor = "red", strokewidth = 1)
image_annotate(img, "Strokewidth Test", size = 60, strokecolor = "red", strokewidth = 2)

[jeroen]

Does NULL (the default) really become 0 when the R integer vector is coerced to a double?

[retowyss]

I don't know. I believe the default in magick is 1 and I've set the default in image_annotate to 1. I haven't tested behavior if 0 is allowed. I haven't tested behavior if strokecolor isn't set but strokewidth is set either. So maybe some additional checks may be necessary; I don't have much familiarity with magick. I assume non-integer values may be non-sense but then I wasn't sure whether it's the job of this package to catch that.

[jeroen]

Thanks!