From: Antonio Ospite <ao2@ao2.it>
Date: Fri, 30 Nov 2018 10:29:09 +0000 (+0100)
Subject: full_range_monthly.gnuplot: fix sampling when drawing boxes
X-Git-Url: https://git.ao2.it/experiments/gnuplot_seasonal_plot.git/commitdiff_plain/d2f20bb5c7a6313c76580ff953a0abfd7ee1cf17?hp=d2f20bb5c7a6313c76580ff953a0abfd7ee1cf17

full_range_monthly.gnuplot: fix sampling when drawing boxes

Instead of working around the problem by doubling the sample rate, fix
the actual problem and prevent different samples to refer to the same
box, resulting in holes in the background.

The solution is to have samples fall in the middle of months instead of
their boundaries, this compensates for the fact that different months
having a slightly different number of days.

Now two different samples are always in two different months.
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