How exactly to handle point sizes?

[Mojca M. <moj...@gm...>]

Hello,

I don't understand how exactly the terminal should handle pointsize.
README says:

  There is a global variable 'pointsize' which is controlled by the
  set pointsize command. If possible, use that. pointsize should be
  examined at terminal init. If it is subsequently changed, the
  pointsize() function will be called.

But what exactly does that mean? Suppose that someone says

set pointsize 5
plot sin(x) with points ps 3

Should the resulting line be 3 or 15 units wide (PS draws 3, windows
draws 15)? The very weird part is that gnuplot sets the pointsize at
the end of plot to the "set pointsize" value. I thought that "set
pointsize X" is only a scaling factor, not a default option passed to
"with points ps X"

Result - if I do this with the windows terminal:
   set pointsize 5
   plot sin(x) with points
then I get points that are 25 units big (windows interprets 5 as
scaling factor and then multiplies the point size with 5 since gnuplot
sets that the pointsize to 5 explicitely). Is this normal?
   plot sin(x) with points ps 1
will plot them 5 units big, but I wonder if 25 units is OK.

PostScript doesn't care about setting that value at the beginning, so
   set pointsize 5
   plot sin(x) with points ps 1
will create points which are exactly one unit big, but
   set pointsize 5
   plot sin(x) with points
is 5 units. According to my understanding the first example should
give 5 units as well. I understand "set pointsize" being a scaling
factor for any point size mentioned later, but the behavior in
different terminals is pretty confusing anyway.

Thanks for explanation,
    Mojca