gnuplot-info — For questions and discussion about gnuplot

[Gnuplot-info] Gnuplot text scaling problem on Windows

[Teodoro S. <Teo...@es...>]

Hi all,

I have a problem with gnuplot text scaling, which is different depending on the computer where my script is run.
I use the pngcairo terminal with gnuplot 4.6.6 to plot my figures under Windows OS, for example:
set term pngcairo enhanced font "Arial,12" size 960, 720 rounded

And I let other colleagues use the code to produce their own figures, but it seems that for some of them the text in the images is scaled.

It seems that it is related to the Windows OS font scaling, where you can choose in the Control Panel to enlarge the fonts of the OS.
This Windows configuration affects the text size of the images, which are prepared for a "normal" font size.
Is there any way to avoid this so to use the same scripts for every computer?

Thank you,
Teo

[Gnuplot-info] pdfcairo: superscript in legend shifts text baseline

[Elias A. <eli...@gm...>]

Hi List,

In gnuplot 5.0 using the pdfcairo terminal, a superscript in a key entry 
shifts that entries baseline.  Compare the following two plots:

set term pdf font ",20"
set out "test.pdf"; p 1 t 'X', 2 t 'Y^y', 3 t 'X', 4 t 'Y', 5 t 'X'; set out

Is there a way to disable or work around this shift?  I would like to 
avoid it because (1) the resulting different line spacings just look 
ugly, and (2) it shifts the text relative to the line sample.

Thanks,

	Elias

[Gnuplot-info] puting multiple labels with multiple offsets on X-Y chart

[Mahmood N <nt_...@ya...>]

I have a data point file like this
"abcd"   0.3   0.7"efgh"   0.4   0.2
I want to create a x-y chart and put "abcd" and "efgh" with custom offsets. The following command
plot "data.txt"  using 2:3:1 with labels point pt 7 offset 1,1
sets the offset for all labels, so some labels may overlap each other. I want to put the first one on "offset 1,1" and put the second one on "offset 2,0"
How can I do that? Regards,
Mahmood

Re: [Gnuplot-info] export jpg to eps format

[Kristoffer Ryhl-J. <kri...@ry...>]

If you mean how to create a eps format graph with gnuplot you can use `set
terminal postscript`

- Kristoffer Ryhl-Johansen

Email: kri...@ry...
Tlf: +45  23 70 75 12


2015-04-24 15:42 GMT+02:00 Roshni Rajkumari <raj...@gm...>:

> How do i export a .jpg file to .eps format
>
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Re: [Gnuplot-info] export jpg to eps format

[Sridhar M A <ala...@gm...>]

On Fri, Apr 24, 2015 at 7:12 PM, Roshni Rajkumari
<raj...@gm...> wrote:
>
> How do i export a .jpg file to .eps format

What has gnuplot to do with this?

If you have imagemagick installed, it is quite simple:

   convert file.jpg file.eps

Of course, there are quite a lot options to control the conversion.

Regards,

[Gnuplot-info] export jpg to eps format

[Roshni R. <raj...@gm...>]

How do i export a .jpg file to .eps format

Re: [Gnuplot-info] setting dimensions in legend box

[theozh <th...@gm...>]

It's not clear to me, what exactly do you want to achieve?

Check out: help key

For example:

set key box width 2 height -1

gives you 2 characters more in width and one character less in height of
the surrounding box.

[Gnuplot-info] setting dimensions in legend box

[Roshni R. <raj...@gm...>]

How to set length and breadth of legend box.

set key box left

I want to put dimension in the box.


Thank You

Re: [Gnuplot-info] Weird colours on 5.0

[Dave H. <da...@ho...>]

Skip it...  I had forgotten that:

a) the printer has a printer test,
b) a colour printer uses CMY, not RGB,
c) the indicated tank levels are not even vaguely accurate.

After much cleaning etc, I realised that the Magenta tank was practically 
empty!  I was wondering why, over its history, all three levels were 
dropping at the same rate...  My next colour printer will have separate 
C/M/Y tanks.

I shall now don sackcloth and ashes, and make sobbing sounds and 
appropriate atonement.

Sorry for wasting everyone's time over what was basically a fundamental 
matter.

-- 
Dave Horsfall DTM (VK2KFU)   "Those who don't understand security will suffer."
http://www.horsfall.org/spam.html (and check the home page whilst you're there)

[Gnuplot-info] Weird colours on 5.0

[Dave H. <da...@ho...>]

Gnuplot 5.0 p0, on Yosemite 10.10.3

I know that the default colours changed in 5.0 (and I know why), but I 
have an oddity.  The colour "red" shows as red on the display (AquaTerm), 
and in the saved PDF, yet prints as yellow.  Even the reds on "test" show 
as red but print as yellow.  Oh, and "yellow" both displays and prints as 
yellow.

What on earth could be wrong?  The printer (a Canon IP-100) has a combined 
colour tank, so it's not as if I've inserted a yellow instead of red...

It ain't the cartridge, because the same one worked OK on 4.6.

-- 
Dave Horsfall DTM (VK2KFU)   "Those who don't understand security will suffer."
http://www.horsfall.org/spam.html (and check the home page whilst you're there)

[Gnuplot-info] (no subject)

[Priyadarshi P. <dav...@gm...>]

Where is the blog???

please share the link

Re: [Gnuplot-info] png terminal will not print different font size except for the default

[Ethan A M. <eam...@gm...>]

On Thursday, 16 April 2015 07:01:00 PM Jon wrote:
> Thank you very much for your information. But I cannot catch the main idea
> there. I am not familiar with libgd or fontconfig at all. Could you please
> give a more detailed explanation and guide me more closely? I showed
> version long and it returned the following, maybe it helps you to identify
> the issue for me.
> 
>         G N U P L O T
>         Version 4.2 patchlevel 6
>         last modified Sep 2009
>         System: Linux 2.6.32-220.el6.x86_64

Many versions out of date, but nevertheless it should work properly.


> Compile options:
> -READLINE  +LIBREADLINE  +HISTORY  +BACKWARDS_COMPATIBILITY  +BINARY_DATA
> +GD_PNG  +GD_JPEG  +GD_TTF  +GD_GIF  +ANIMATION
                     ^^^^^^^^
Yes, your copy of gnuplot does link to a libgd that support TrueType fonts.


> -NOCWDRC  +X11  +X11_POLYGON  +MULTIBYTE  +USE_MOUSE  +HIDDEN3D_QUADTREE
> +DATASTRINGS  +HISTOGRAMS  +OBJECTS  +STRINGVARS  +MACROS  +IMAGE


Sorry, I can't help you beyond this.  It looks to me that there is
nothing wrong with your gnuplot, and the problem must lie elsewhere.
As a final test, I suggest you copy some well-known *.ttf font into
your current directly and test again using that font.

For example:

$ cp /somewhere/arial.ttf .
$ gnuplot
gnuplot>  set term png enhanced font "./arial.ttf"
gnuplot>  set title "{/=24 Big Title}" 
gnuplot>  set output "426.png"
gnuplot>  plot x
gnuplot>  quit

$ display 426.png

I just tested that here using an old copy of gnuplot_4.2.6 and
it works for me.

	Ethan




> 
> 
> 
> On Thu, Apr 16, 2015 at 6:11 PM, Ethan Merritt <eam...@gm...> wrote:
> 
> > On Thu, Apr 16, 2015 at 3:05 PM, Jon <dev...@gm...> wrote:
> > > could you please give me your configure file relevant to gnuplot?
> > >
> > > What I am using are copied from online as
> > >
> > > export GDFONTPATH=/usr/share/fonts/liberation
> > > export GNUPLOT_DEFAULT_GDFONT=LiberationSans-Regular
> > >
> > > which does exist under the specific directory but obviously not perfect.
> > How
> > > to check whether these are compatible with my current version of gnuplot?
> > >
> > > Thanks,
> > >
> > >
> > >
> > > On Thu, Apr 16, 2015 at 4:18 PM, Ethan Merritt <eam...@gm...>
> > wrote:
> > >>
> > >> I do not know why/how your system is [mis]configured so that it does
> > >> not find fonts by default, but you can use the environmental variable
> > >> GDFONTPATH to give libgd a new list of directories to use for font
> > >> lookup.  Of course it will only find fonts that are actually present
> > >> in those directories.
> >
> > I don't think the gnuplot version is relevant here.  The only thing
> > that matters is libgd.
> >
> > I think that all versions of libgd will accept a font by path and
> > filename (as you show in your export commands above).  libgd versions
> > newer than (I think) 2.0.35 will also accept a font specified by its
> > face name, in which case the system fontconfig utility is used to
> > search for it. In either case gnuplot just passes through the
> > requested font name and size to libgd; it doesn't do any font
> > management by itself.
> >
> > It is in principle possible to have a copy of libgd that doesn't
> > support TrueType or OpenType fonts, but I haven't seen such a thing
> > since last century.   This is tested at the time gnuplot is configured
> > and the result is indicated by defining (or not) the symbol
> > HAVE_GD_TTF in file config.h.  You can also check this from inside
> > gnuplot by typing "show version long" and looking for the string
> > "+GD_TTF".
> >

Re: [Gnuplot-info] png terminal will not print different font size except for the default

[BBands <bb...@gm...>]

There is quite a bit of info on gd here:

http://www.boutell.com/gd/manual2.0.33.html

Many have moved on from gd for png support, so help may be hard to come by.

Here is a snippet from the 4.6 release note:

The 4.6 source code supports three primary cross-platform output modes
in addition to several platform-specific modes.

1) Cairo/pango/wxWidgets
   These terminals were introduced in version 4.4 and are now the most
   stable and full-featured option.  This set of terminals includes
   - pngcairo, pdfcairo, epscairo, and cairolatex for output to a file
   - wxt for interactive display
   This is the default configuration, but requires prior installation of
   libcairo, libpango, libcairo, libwxgtk, and related support libraries
   To disable these terminals:
       ./configure --disable-wxt --without-cairo

2) Qt
   The new qt terminal supports interactive display with menu-driven
   output to png, svg or pdf.
   Requires libqt version >= 4.5
       ./configure --enable-qt

    John

On Thu, Apr 16, 2015 at 5:01 PM, Jon <dev...@gm...> wrote:

> Thank you very much for your information. But I cannot catch the main idea
> there. I am not familiar with libgd or fontconfig at all. Could you please
> give a more detailed explanation and guide me more closely? I showed
> version long and it returned the following, maybe it helps you to identify
> the issue for me.
>
>         G N U P L O T
>         Version 4.2 patchlevel 6
>         last modified Sep 2009
>         System: Linux 2.6.32-220.el6.x86_64
>
>         Copyright (C) 1986 - 1993, 1998, 2004, 2007 - 2009
>         Thomas Williams, Colin Kelley and many others
>
>         Type `help` to access the on-line reference manual.
>         The gnuplot FAQ is available from http://www.gnuplot.info/faq/
>
>         Send bug reports and suggestions to <
> http://sourceforge.net/projects/gnuplot>
>
> Compile options:
> -READLINE  +LIBREADLINE  +HISTORY  +BACKWARDS_COMPATIBILITY  +BINARY_DATA
> +GD_PNG  +GD_JPEG  +GD_TTF  +GD_GIF  +ANIMATION
> -NOCWDRC  +X11  +X11_POLYGON  +MULTIBYTE  +USE_MOUSE  +HIDDEN3D_QUADTREE
> +DATASTRINGS  +HISTOGRAMS  +OBJECTS  +STRINGVARS  +MACROS  +IMAGE
>
> DRIVER_DIR     = "/usr/libexec/gnuplot/4.2"
> GNUPLOT_PS_DIR = "/usr/share/gnuplot/4.2/PostScript"
> HELPFILE       = "/usr/share/gnuplot/4.2/gnuplot.gih"
>

Re: [Gnuplot-info] png terminal will not print different font size except for the default

[Jon <dev...@gm...>]

Thank you very much for your information. But I cannot catch the main idea
there. I am not familiar with libgd or fontconfig at all. Could you please
give a more detailed explanation and guide me more closely? I showed
version long and it returned the following, maybe it helps you to identify
the issue for me.

        G N U P L O T
        Version 4.2 patchlevel 6
        last modified Sep 2009
        System: Linux 2.6.32-220.el6.x86_64

        Copyright (C) 1986 - 1993, 1998, 2004, 2007 - 2009
        Thomas Williams, Colin Kelley and many others

        Type `help` to access the on-line reference manual.
        The gnuplot FAQ is available from http://www.gnuplot.info/faq/

        Send bug reports and suggestions to <
http://sourceforge.net/projects/gnuplot>

Compile options:
-READLINE  +LIBREADLINE  +HISTORY  +BACKWARDS_COMPATIBILITY  +BINARY_DATA
+GD_PNG  +GD_JPEG  +GD_TTF  +GD_GIF  +ANIMATION
-NOCWDRC  +X11  +X11_POLYGON  +MULTIBYTE  +USE_MOUSE  +HIDDEN3D_QUADTREE
+DATASTRINGS  +HISTOGRAMS  +OBJECTS  +STRINGVARS  +MACROS  +IMAGE

DRIVER_DIR     = "/usr/libexec/gnuplot/4.2"
GNUPLOT_PS_DIR = "/usr/share/gnuplot/4.2/PostScript"
HELPFILE       = "/usr/share/gnuplot/4.2/gnuplot.gih"




On Thu, Apr 16, 2015 at 6:11 PM, Ethan Merritt <eam...@gm...> wrote:

> On Thu, Apr 16, 2015 at 3:05 PM, Jon <dev...@gm...> wrote:
> > could you please give me your configure file relevant to gnuplot?
> >
> > What I am using are copied from online as
> >
> > export GDFONTPATH=/usr/share/fonts/liberation
> > export GNUPLOT_DEFAULT_GDFONT=LiberationSans-Regular
> >
> > which does exist under the specific directory but obviously not perfect.
> How
> > to check whether these are compatible with my current version of gnuplot?
> >
> > Thanks,
> >
> >
> >
> > On Thu, Apr 16, 2015 at 4:18 PM, Ethan Merritt <eam...@gm...>
> wrote:
> >>
> >> I do not know why/how your system is [mis]configured so that it does
> >> not find fonts by default, but you can use the environmental variable
> >> GDFONTPATH to give libgd a new list of directories to use for font
> >> lookup.  Of course it will only find fonts that are actually present
> >> in those directories.
>
> I don't think the gnuplot version is relevant here.  The only thing
> that matters is libgd.
>
> I think that all versions of libgd will accept a font by path and
> filename (as you show in your export commands above).  libgd versions
> newer than (I think) 2.0.35 will also accept a font specified by its
> face name, in which case the system fontconfig utility is used to
> search for it. In either case gnuplot just passes through the
> requested font name and size to libgd; it doesn't do any font
> management by itself.
>
> It is in principle possible to have a copy of libgd that doesn't
> support TrueType or OpenType fonts, but I haven't seen such a thing
> since last century.   This is tested at the time gnuplot is configured
> and the result is indicated by defining (or not) the symbol
> HAVE_GD_TTF in file config.h.  You can also check this from inside
> gnuplot by typing "show version long" and looking for the string
> "+GD_TTF".
>

Re: [Gnuplot-info] png terminal will not print different font size except for the default

[Ethan M. <eam...@gm...>]

On Thu, Apr 16, 2015 at 3:05 PM, Jon <dev...@gm...> wrote:
> could you please give me your configure file relevant to gnuplot?
>
> What I am using are copied from online as
>
> export GDFONTPATH=/usr/share/fonts/liberation
> export GNUPLOT_DEFAULT_GDFONT=LiberationSans-Regular
>
> which does exist under the specific directory but obviously not perfect. How
> to check whether these are compatible with my current version of gnuplot?
>
> Thanks,
>
>
>
> On Thu, Apr 16, 2015 at 4:18 PM, Ethan Merritt <eam...@gm...> wrote:
>>
>> I do not know why/how your system is [mis]configured so that it does
>> not find fonts by default, but you can use the environmental variable
>> GDFONTPATH to give libgd a new list of directories to use for font
>> lookup.  Of course it will only find fonts that are actually present
>> in those directories.

I don't think the gnuplot version is relevant here.  The only thing
that matters is libgd.

I think that all versions of libgd will accept a font by path and
filename (as you show in your export commands above).  libgd versions
newer than (I think) 2.0.35 will also accept a font specified by its
face name, in which case the system fontconfig utility is used to
search for it. In either case gnuplot just passes through the
requested font name and size to libgd; it doesn't do any font
management by itself.

It is in principle possible to have a copy of libgd that doesn't
support TrueType or OpenType fonts, but I haven't seen such a thing
since last century.   This is tested at the time gnuplot is configured
and the result is indicated by defining (or not) the symbol
HAVE_GD_TTF in file config.h.  You can also check this from inside
gnuplot by typing "show version long" and looking for the string
"+GD_TTF".

Re: [Gnuplot-info] png terminal will not print different font size except for the default

[Jon <dev...@gm...>]

could you please give me your configure file relevant to gnuplot?

What I am using are copied from online as

export GDFONTPATH=/usr/share/fonts/liberation
export GNUPLOT_DEFAULT_GDFONT=LiberationSans-Regular

which does exist under the specific directory but obviously not perfect.
How to check whether these are compatible with my current version of
gnuplot?

Thanks,



On Thu, Apr 16, 2015 at 4:18 PM, Ethan Merritt <eam...@gm...> wrote:

> I do not know why/how your system is [mis]configured so that it does
> not find fonts by default, but you can use the environmental variable
> GDFONTPATH to give libgd a new list of directories to use for font
> lookup.  Of course it will only find fonts that are actually present
> in those directories.
>

Re: [Gnuplot-info] png terminal will not print different font size except for the default

[Ethan M. <eam...@gm...>]

I do not know why/how your system is [mis]configured so that it does
not find fonts by default, but you can use the environmental variable
GDFONTPATH to give libgd a new list of directories to use for font
lookup.  Of course it will only find fonts that are actually present
in those directories.

Re: [Gnuplot-info] png terminal will not print different font size except for the default

[Jon <dev...@gm...>]

I tried to run your script and gnuplot returns

gdImageStringFT: Could not find/open font while printing string test with
font arial

any idea? This is tested on gnuplot 4.2.6. I also tried on gnuplot 5.0
which directly says png terminal not recognized.

Many thanks!



On Thu, Apr 16, 2015 at 1:23 PM, BBands <bb...@gm...> wrote:

> On Linux with gnuplot 5.0:
>
> set term png
> set label "test" font 'arial, 24'
> set output "test.png"
> plot sin(x)
> set output
>
> Produces a png file of a sine wave with a large "test" in the center for
> me. All the test features of the test plot work for me in png too.
>
> Devs: Should we have some different font sizes in the test function?
>
>     John
>
>
> On Thu, Apr 16, 2015 at 9:19 AM, Jon <dev...@gm...> wrote:
>
>> Dear All users,
>>
>> I have been frustrated by this issue for a long time. For the png terminal
>> I checked on my local linux environment always gives the same font size no
>> matter what size I request. Any idea on how to fix it? If further
>> information or sample script is needed, please let me know.
>>
>
>

Re: [Gnuplot-info] png terminal will not print different font size except for the default

[BBands <bb...@gm...>]

On Linux with gnuplot 5.0:

set term png
set label "test" font 'arial, 24'
set output "test.png"
plot sin(x)
set output

Produces a png file of a sine wave with a large "test" in the center for
me. All the test features of the test plot work for me in png too.

Devs: Should we have some different font sizes in the test function?

    John

On Thu, Apr 16, 2015 at 9:19 AM, Jon <dev...@gm...> wrote:

> Dear All users,
>
> I have been frustrated by this issue for a long time. For the png terminal
> I checked on my local linux environment always gives the same font size no
> matter what size I request. Any idea on how to fix it? If further
> information or sample script is needed, please let me know.
>

[Gnuplot-info] png terminal will not print different font size except for the default

[Jon <dev...@gm...>]

Dear All users,

I have been frustrated by this issue for a long time. For the png terminal
I checked on my local linux environment always gives the same font size no
matter what size I request. Any idea on how to fix it? If further
information or sample script is needed, please let me know.

Thanks,

Sincerely,
Jon

Re: [Gnuplot-info] Short horizontal line become exaggerated in saved plots

[Rob S. <rob...@ut...>]

On 04/14/2015 02:44 PM, Hans-Bernhard Bröker wrote:
> Am 14.04.2015 um 01:40 schrieb Rob Sargent:
>> Hoping third times the charm, with this posting.  My first was rejected
>> as not-a-member, the second seems to have simply wafted away...
>>
>> I'm running gnuplot 4.2 patchlevel 6 on RHEL 6.6.
>
> Well, that version is old: 5.5 years.  So the first and foremost 
> suggestion must be: update to something at least remotely current, 
> like 4.6 pl 6, or even 5.0
>
 From where I sit, that's the release on RHEL. I do have rpm's for 4.6 
but I'm hesitant to rock the install boat for this utility. Call me 
chicken but several attempt to modernize RHEL 6 have been troublesome.
>> I draw a number of (usually quite short) lines 4pt thick throughout the
>> plot. In the interactive window these are so short they are often barely
>> visible (and that's a good thing). But they become exaggerated in the
>> (viewing of) the saved plot, using jpeg, png or gif.
>
> Well, what do you expect a discrete, pixel-based terminal to do? You 
> didn't even reveal how big you make those images...
I typically define the window as 1600x400 for the saved images. 
Interactively I do not specify a window geometry; simply stretch the 
window and play with regions using the right-click-drag.
>
>> each of them is plotted from a generated file of this form:
>>
>>      1    23057190    2.709457    0.000000    23057190
>>      1    24552835    2.709457    0.000000    24552835
>
> That's a line covering just 1/2000th of your x axis range.  That 
> leaves a normal-sized pixel image only one of two choices: display 
> nothing at all, or display at least one pixel.  Neither of which you 
> appear to want.  So what did you expect to happen?
Perhaps I expect too much.  The interactive viewer (x11) does a 
perfectly acceptable single pixel rendering.  I'm confused why in the 
saved images, in multiple formats, viewed by a variety of tools, these 
barely noticeable lines are puffed up. Oh and whether or not I can do 
anything about it - if it's a problem in the save-to-file action of 
gnuplot I will upgrade to 4.6 (maybe 5) if this is a known, and fixed, 
issue.

Thanks,
rjs

Re: [Gnuplot-info] Short horizontal line become exaggerated in saved plots

[Hans-Bernhard B. <HBB...@t-...>]

Am 14.04.2015 um 01:40 schrieb Rob Sargent:
> Hoping third times the charm, with this posting.  My first was rejected
> as not-a-member, the second seems to have simply wafted away...
>
> I'm running gnuplot 4.2 patchlevel 6 on RHEL 6.6.

Well, that version is old: 5.5 years.  So the first and foremost 
suggestion must be: update to something at least remotely current, like 
4.6 pl 6, or even 5.0

> I draw a number of (usually quite short) lines 4pt thick throughout the
> plot. In the interactive window these are so short they are often barely
> visible (and that's a good thing). But they become exaggerated in the
> (viewing of) the saved plot, using jpeg, png or gif.

Well, what do you expect a discrete, pixel-based terminal to do? You 
didn't even reveal how big you make those images...

> each of them is plotted from a generated file of this form:
>
>      1    23057190    2.709457    0.000000    23057190
>      1    24552835    2.709457    0.000000    24552835

That's a line covering just 1/2000th of your x axis range.  That leaves 
a normal-sized pixel image only one of two choices: display nothing at 
all, or display at least one pixel.  Neither of which you appear to 
want.  So what did you expect to happen?

Re: [Gnuplot-info] set palette maxcolors different behavior in 5.0?

[Patrick A. <pat...@Co...>]

> 
> Moreland gives the generating equations for the MSH color space used
> to generate the palette you started with.  You could either use these to
> describe a continuous palette using "set palette functions" or you could
> contribute a new bit of code to select the MSH colorspace as an alternative
> to RGB/CMY/HSV/YIQ/etc.   Either way the "maxcolors" option would then
> work to sample from a continuous palette.
> 
> Here is a quick try at defining a similar (but not exact) continuous palette:
> 
>         R(x) = 0.2 + 0.8 * sin(x*2.2)
>         B(x) = 0.2 + 0.8 * sin(0.9 + x*2.2)
>         G(x) = 0.3 + 0.83 * sin(x * 3.) - 0.4*x
>         set palette functions R(gray), G(gray), B(gray)
>         set palette maxcolors 5
>         test palette
> 
> If those continuous functions are not close enough to the Moreland palette,
> you can replace them with the equations from the paper.
> 
>     Ethan
> 

Ok, thanks for the info. It does seem that the 'x11' terminal is doing
some sort of simple interpolation on the 256 points to honor the
maxcolors 5 setting. This should be trivial to implement for the other
terminals, but I won't push the issue any more.

[Gnuplot-info] Short horizontal line become exaggerated in saved plots

[Rob S. <rob...@ut...>]

Hoping third times the charm, with this posting.  My first was rejected 
as not-a-member, the second seems to have simply wafted away...

I'm running gnuplot 4.2 patchlevel 6 on RHEL 6.6.

I draw a number of (usually quite short) lines 4pt thick throughout the 
plot. In the interactive window these are so short they are often barely 
visible (and that's a good thing). But they become exaggerated in the 
(viewing of) the saved plot, using jpeg, png or gif.

My line style for these is: set style line 4 linewidth 4 lc rgb "#8550FF"

each of them is plotted from a generated file of this form:

    1    23057190    2.709457    0.000000    23057190
    1    24552835    2.709457    0.000000    24552835

with this directive:

    plot ... redo/1801/wpw/runAvgRatio.0163257164" using 2:3 title ""
    axes x1y2 ls 4 with line [,another/file]*

and there are hundreds of them. the X values are base position on a 
chromosome scaled to full genome (0..3,000,000,000)

I view the saved images in either emacs (I know) or gimp or "eye of 
GNOME" and see the same bloat.

Does anyone have an explanation, or better yet a solution?

Happy to ship my plotable file, but keep in mind it references lots of 
the line files.

Re: [Gnuplot-info] set palette maxcolors different behavior in 5.0?

[Ethan M. <eam...@gm...>]

On Mon, Apr 13, 2015 at 10:53 AM, Patrick Alken
<pat...@co...> wrote:
>
>> There was a change in handling "maxcolors", but the change came several
>> years ago.  It is not connected to version 4 / version 5.
>> I think the new behavior was first introduced in 4.4.3 (Mar 2011) and
>> tweaked a bit in later versions.
>>
>> The change is that terminals with full RGB color support will always
>> give you any explicitly requested color.  That is, "maxcolors" will
>> determine how many subdivisions are made for an interpolated palette,
>> e.g.
>>      set palette defined (0 "red", 1 "blue") maxcolors 5
>>      test palette
>> But if you request, say, 20 explicit color ranges you will get all
>> of them even though you said "maxcolors 5"
>
> I don't understand the purpose of maxcolors then. As a user I want the
> ability to switch between a continuous or discrete palette

That is exactly what "maxcolors" can do.
But you didn't have a continuous palette.  You had a 256-color discrete palette.
Maxcolors does not magically select 5 of your 256 colors and throw
away the rest.

Moreland gives the generating equations for the MSH color space used
to generate the palette you started with.  You could either use these to
describe a continuous palette using "set palette functions" or you could
contribute a new bit of code to select the MSH colorspace as an alternative
to RGB/CMY/HSV/YIQ/etc.   Either way the "maxcolors" option would then
work to sample from a continuous palette.

Here is a quick try at defining a similar (but not exact) continuous palette:

        R(x) = 0.2 + 0.8 * sin(x*2.2)
        B(x) = 0.2 + 0.8 * sin(0.9 + x*2.2)
        G(x) = 0.3 + 0.83 * sin(x * 3.) - 0.4*x
        set palette functions R(gray), G(gray), B(gray)
        set palette maxcolors 5
        test palette

If those continuous functions are not close enough to the Moreland palette,
you can replace them with the equations from the paper.

    Ethan

> I shouldn't need to condense my 256 color palette down to 8 colors myself
> in order to achieve this. It seems to me that should be the purpose of
> the maxcolors feature.

> Since I manage to get my desired result in the 'x11' terminal I will
> continue using that. But it sounds like when I try to print to png or
> pdf, I may end up with a different plot.
>
> Could I request that the maxcolors be changed to automatically define
> discrete color levels even if more colors are provided in the palette?