Use raw series for y-axis ticks when log = TRUE

This creates y-axis labels using the raw series values, instead of the
log series values. So the labels and locations are in round values of
the raw series, but rendered at the logged locations.

See #103.

R/plot.R

@@ -1233,8 +1233,18 @@ new.replot_xts <- function(panel=1,asp=1,xlim=c(1,10),ylim=list(structure(c(1,10
  }
 
  # y-axis grid line labels and locations
- grid_loc <- pretty(yl, Env$yaxis.ticks)
- grid_loc <- grid_loc[grid_loc >= yl[1] & grid_loc <= yl[2]]
+ if (use_log_yaxis) {
+ # labels are based on the raw series values
+ ylim_series <- exp(yl)
+ grid_lbl <- pretty(ylim_series, Env$yaxis.ticks)
+ grid_lbl <- grid_lbl[grid_lbl >= ylim_series[1] & grid_lbl <= ylim_series[2]]
+ # locations are based on the log series values
+ grid_loc <- log(grid_lbl)
+ } else {
+ grid_loc <- pretty(yl, Env$yaxis.ticks)
+ grid_loc <- grid_loc[grid_loc >= yl[1] & grid_loc <= yl[2]]
+ grid_lbl <- grid_loc
+ }
 
  # draw y-axis grid lines
  segments(x0 = xlim[1], y0 = grid_loc,
@@ -1247,7 +1257,7 @@ new.replot_xts <- function(panel=1,asp=1,xlim=c(1,10),ylim=list(structure(c(1,10
  if (draw_left_yaxis) {
  text(x = xlim[1],
  y = grid_loc,
- labels = format(grid_loc, justify = "right"),
+ labels = format(grid_lbl, justify = "right"),
  col = theme$labels,
  srt = theme$srt,
  offset = 0.5,
@@ -1260,7 +1270,7 @@ new.replot_xts <- function(panel=1,asp=1,xlim=c(1,10),ylim=list(structure(c(1,10
  if (draw_right_yaxis) {
  text(x = xlim[2],
  y = grid_loc,
- labels = format(grid_loc, justify = "right"),
+ labels = format(grid_lbl, justify = "right"),
  col = theme$labels,
  srt = theme$srt,
  offset = 0.5,