Re: [ferret_users] pyferret frame images with nodisplay have small white lines

Hi Patrick,

The "outline" setting in pyferret is to address the white lines that can occur when any graphics program draws a plot using filled polygons. Shade and fill plots draw color-filled rectangles or triangles. Here is a post about this, and there are other discussions going back a long time. This occurred with Ferret graphics too.

../fu_2019/msg00711.html

Your example used the shade command. If the desired plot uses a contour/fill, then another workaround is to first draw a shade plot and then overlay a fill plot with identical colors.

Ansley

On Fri, Jan 22, 2021, 7:46 AM Patrick Brockmann <patrick.brockmann@xxxxxxxxxxxx> wrote:

Hi,

import pyferret
pyferret.start(verify=False, pngonly=True, journal=False, quiet=True)
pyferret.run('set window /xpixel=756.000000 /aspect=0.809524 /outline=0.0 1')
pyferret.run('use levitus_climatology')
pyferret.run('shade/lev=20v temp[k=1]')
pyferret.run('frame/file=tyty.png')

still produces an image with this an annoying thin white horizontal line.
Hi all,

With pyferret and the -nodisplay option I get some white horizontal lines
that makes the image captured by the frame command not very nice (at least strange).

Is there a workaround ?
Initially (re)discovered from a python notebook (with ferretmagic https://github.com/PBrockmann/ipython_ferretmagic)

$ cat tyty.jnl
use levitus_climatology
shade/lev=20v temp[k=1]
frame/file=tyty.png

$ pyferret -nodisplay -script tyty.jnl

I have tested the pyferret -png option.
It produces an image without lines. That would be perfect but how to retrieve this mode
from a pyferret.start function (the way ferretmagic produces images).

Please test:

$cat tyty.py
import pyferret
pyferret.start(verify=False, journal=False, unmapped=True, quiet=True)
pyferret.run('use levitus_climatology')
pyferret.run('shade/lev=20v temp[k=1]')
pyferret.run('frame/file=tyty.png')

$python tyty.py

Tested with last 7.63 release

Regards
Patrick

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Data Analytics and Visualization Engineer / Project Manager
LSCE/IPSL, CEA-CNRS-UVSQ laboratory
LSCE - Climate and Environment Sciences Laboratory
IPSL - Institut Pierre Simon Laplace
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