Re: [Gnuplot-info] non-working linewidth and dashpattern in epslatex terminal?

[David K. <da...@gn...>]

Ethan Merritt <eam...@gm...> writes:

> On Tue, Oct 17, 2017 at 6:38 AM, David Kastrup <da...@gn...> wrote:
>
>> Ethan A Merritt <eam...@gm...> writes:
>>
>> > On Sunday, 15 October 2017 10:53:08 Ethan A Merritt wrote:
>> >> On Sunday, 15 October 2017 13:06:50 David Kastrup wrote:
>> >> >
>> >> > So I now tried compiling 5.2.0.
>> >> >
>> >> > No change in the epslatex terminal: it would appear that _only_ the
>> >> > linewidth and the dash pattern for linestyle 1 are ever consulted and
>> >> > are used for _all_ lines.  Linecolor can be changed per line style,
>> but
>> >> > pretty much nothing else.
>> >>
>> >> Correct.  It steps through sequential line colors.
>> >>
>> >> > Anybody have a good idea for where to patch this up?
>> >>
>> >> The following 1-line change might or might not produce acceptable
>> >> results for you.   One problem is that the line segments making up
>> >> a contour are not necessarily drawn in order and some terminals
>> >> reset the dash pattern for each segment, leading to mostly solid
>> >> or mostly missing lines rather than the desired dash pattern.
>> >> For other terminal types this doesn't seem to be a problem.
>> >>
>> >> If this does work for you please report back.
>> >> We could make it an optional setting of some sort.
>>
>> I don't think following the documentation is "optional".
>>
>> [snip]
>
> I think I understand what you are expecting from the program, but honestly
> it has never worked that way.

Shrug.  Of course not: dash types as part of line style were a 5.0
thing.  Before one used

set terminal epslatex dashed

but dashed is now ignored, and the _documented_ replacement one is
supposed to be using does not work.  And now you state it shouldn't
work, documentation be damned.  But in a monochrome print, having all
contour lines look the same is not an option.

> You are now, as I understand it, advocating that both the linewidth
> and dashtype properties should act as the linecolor does.  I'm fine
> with adding that as a user-specified option, but it would be something
> new rather than a return to what any previous gnuplot version did.

Look, this isn't fun.

help dash

clearly states:

gnuplot> help dash

In gnuplot version 5 the dash pattern (`dashtype`) is a separate property 
 associated with each line, analogous to `linecolor` or `linewidth`.  It is not
 necessary to place the current terminal in a special mode just to draw dashed
 lines.  I.e. the command `set term <termname> {solid|dashed}` is now ignored.
 If backwards compatibility with old scripts written for version 4 is required,
 the following lines can be used instead:

      if (GPVAL_VERSION >= 5.0) set for [i=1:9] linetype i dashtype i
      if (GPVAL_VERSION < 5.0) set termoption dashed

So _of_ _course_ this worked differently before version 5.0.  The
problem is that it _worked_.  Now it doesn't work at all.  There is
absolutely no more way to get differently dashed contours in a
monochrome terminal since the documented replacement does not work, and
you state that you think it should be an optional feature to have it
work.

> Note: Your expectation may be colored by past behaviour of the
> postscript terminal driver.

My expectation is colored by current documentation that is supposed to
reflect the change from 4.x to 5.x.  It is not like I didn't quote it.
As it is, Gnuplot is useless for creating monochrome surface plots with
contours because all contour lines will look the same.  This wasn't the
case in Gnuplot 4.x, and the documented replacement for versions >= 5.0
does not work.

-- 
David Kastrup