Streamline steps go from 0 to N

NEWS.md

@@ -11,6 +11,7 @@
 -   The `GetSMNData()` function is defunct. The functionality is a hack and hard to maintain and it's also very specific and should be out of scope for a general package.
 -   The `trans` argument of scales has been renamed to `transform` following ggplot2's change.
 -   `scale_mag()` internals are now much simpler and inherits all the functionality from common continuous scales. (thanks @teunbrand for the suggestion, #186)
+-   The `step` computed variable in `geom_streamline()` now goes from 0 to the total number of steps instead of from negative half to positive half.
 
 # metR 0.15.0
 

R/geom_streamline.R

@@ -545,6 +545,7 @@ streamline.f <- function(field, dt = 0.1, S = 3, skip.x = 1, skip.y = 1, nx = NU
     points[, group := interaction(group, piece, end)]
     points[, line := group]
 
+    points[, step := seq(0, .N), by = .(group)]
     return(points[, .(x, y, group, piece, end, step, dx, dy, line)])
 }