[Gnuplot-info] Arrow heads do not point exactly to the point they have been directed to

[Mikhail K. <mko...@gm...>]

Hi,

i am building plots with gnuplot 4.4.0 and use a lot of arrows to 
decorate and explain what is displayed on the plots.

however i faced to a problem that arrows with heads do not point 
directly to the point i tell it to.

for postscript or pdf terminal outputs arrow head go behind the point. 
you can see an example of what is happening in the electronic book 
"gnuplot in action", figure 6.2 at page 93, arrows directed to the graph 
area corners (to graph 0,0 and to graph 1,1) if you magnify the corners 
a little.

it is not very nice when it is necessary to have arrows pointing some 
exact position. and this "error" size depends on arrow head size.

for pdfcairo terminal output arrows do not have sharp edges, and that 
actually solved the problem for me because dull arrows which appears on 
that terminal are pointed exactly to a point where they have been set to.

also, for pdfcairo terminal, when i use headless arrows to plot vertical 
lines using "nohead" key:

set arrow 2 from X_VAL, graph 0 to X_VAL, graph 1 hohead lw 1.5 lt 1 lc 
rgb "black"

both line ends go beyond the graph area, and this can bee seen on a 
magnified plot.

is it possible to fix these things in some way other than adjusting 
arrow end positions by hands?

thank you in advance for any response.

Misha.

--

Mikhail Kononets
Ph.D. Student
Department of Chemistry
Marine Chemistry
University of Gothenburg
Kemivagen 10
SE-412 96 Gothenburg, Sweden
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