Re: gnuplot graphics toolkit bugs

[Daniel J Sebald]

On 06/23/2015 12:41 PM, Ben Abbott wrote:
> > On Jun 23, 2015, at 12:58 PM, Daniel J Sebald<address@hidden>  wrote:
> >
> > On 06/23/2015 08:58 AM, Ben Abbott wrote:
> > > > On Jun 23, 2015, at 2:52 AM, Daniel J Sebald<address@hidden>
> >
> > [snip]
> >
> > > > https://savannah.gnu.org/bugs/?func=detailitem&item_id=43907
> > > > bug #43907: OpenGL render code called even when gnuplot is graphics_toolkit
> > > >
> > > > Dan
> > >
> > > Perhaps the most serious gnuplot 5 related bug is below. I’ve attached a patch 
> > > to the bug report, but since I’m not able to build Octave 4.x on Mac OSX, I 
> > > haven’t pushed it.
> > >
> > >         http://savannah.gnu.org/bugs/?42838
> > >
> > > Ben
> >
> > Well, there is a lot there for me to read, but let me just guess that this is 
> > the issue where default EPS mode uses grayscale, not color.  And in gnuplot, 
> > the grayscale mode translates any non-white color to black, technically 
> > monochrome.
>
> Yes. I think that is correct.
>
> > I had addressed this somewhat in the changeset:
> >
> > https://savannah.gnu.org/bugs/?44187
> > bug #44187: Bugs and modifications in print() with gnuplot graphics toolkit
> >
> > by either not plotting the color background or using color terminal but casting 
> > all colors to a grayscale equivalent.  But then I thought that was too much for 
> > one bug report and pulled back so that the black 
> > color-background-translates-to-black issue is still present.
>
> I like the solution of handling the color/gray-scale in Octave (i.e. Gnuplot is 
> always told the to use color). Is that what you mean?

Yes, I tried that, but when combined with the other parts of that 
changeset it simply was too much to follow.  The two ideas should be 
kept separate.

Looking at the changeset here:

http://savannah.gnu.org/bugs/?42838

one of the issues is compatibility.  Octave EPS output should be 
grayscale, not color.  EPSC is color.  Unless I'm overlooking something, 
I suspect more is needed than just choosing "color" option.  I think the 
patch associated with this comment:

https://savannah.gnu.org/bugs/?44187#comment13

still had elements of mapping to grayscale, but again I'm sure it is 
difficult to follow as the use of "mono" means different things in the 
various circumstances.

Dan