stamp_vline.RdHorizontal line, wraps geom_vline w defaut at y = 0
stamp_vline( xintercept = 0, alpha = 1, color = "black", linetype = "solid", size = 1.5 )
| xintercept | x position of vertical line | 
|---|---|
| alpha | numeric between 0 and 1 indicating transparency, defaults to 1 fully opaque, zero is fully transparent | 
| color | a character string indicating color, defaults to "black", for other named colors check out https://evamaerey.github.io/ggplot2_grammar_guide/named_colors | 
| linetype | a string indicating linetype, "solid", "dashed", "dotted", defaults to "solid" | 
| size | numeric value indicating line width, defaults to 1.5 | 
# on a canvas ggcanvas() + stamp_vline(color = "cadetblue") + stamp_vline(0:5, linetype = rep(c("dotted", "dashed"), 3))