Gnuplot - Show different tick color at 0

Question

I want to display different tick color at 0. For eg, the image below I want to set tick color at 0 in y axis to blue. Can it possible? Thanks.

Answer 1

I am not aware of a direct Gnuplot feature that would allow to do this, nevertheless one might use some workaround.

For example, one could unset the tic at position zero and place there a custom label instead:

set terminal pngcairo enhanced font ",14"
set output 'fig.png'

set multiplot

xMin = 0
xMax = 2*pi

set xr [xMin:xMax]
set yr [-1:1]

set xtics out nomirror
set ytics out nomirror 
set ytics add ("" 0)

set label "0" at xMin,0 offset char -1.5,0 right textcolor rgb "blue"

plot sin(x) w l t 'sin(x)'

Alternatively, one could use a technique based on multiplot, where the strategy is basically first to plot the function/data of interest without the tic at position zero and then overlay this with a plot which is empty but for the customized tic at position zero:

set terminal pngcairo enhanced font ",14"
set output 'fig.png'

set xr [0:2*pi]
set yr [-1:1]

set xtics out nomirror
set ytics out nomirror 
set ytics add ("" 0)

plot sin(x) w l t 'sin(x)'

set lmargin at screen GPVAL_TERM_SCALE * GPVAL_TERM_XMIN / (1.*GPVAL_TERM_XSIZE)
set rmargin at screen GPVAL_TERM_SCALE * GPVAL_TERM_XMAX / (1.*GPVAL_TERM_XSIZE)
set bmargin at screen GPVAL_TERM_SCALE * GPVAL_TERM_YMIN / (1.*GPVAL_TERM_YSIZE)
set tmargin at screen GPVAL_TERM_SCALE * GPVAL_TERM_YMAX / (1.*GPVAL_TERM_YSIZE)

unset border
unset key
unset xtics
unset ytics

set ytics ("0" 0) out nomirror textcolor rgb 'blue'

plot 1/0

Both approaches result in a nearly identical plot: