[Octave-bug-tracker] [bug #53056] LineWidth interpreted as pixels, not points

[Rik]

URL:
  <http://savannah.gnu.org/bugs/?53056>

                 Summary: LineWidth interpreted as pixels, not points
                 Project: GNU Octave
            Submitted by: rik5
            Submitted on: Sat 03 Feb 2018 04:04:31 AM PST
                Category: Plotting with OpenGL
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Matlab Compatibility
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: dev
        Operating System: Any

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Details:

According to Matlab documentation, LineWidth and MarkerSize for line objects
are specified in points.  In Octave, we use the OpenGL function glLineWidth
which sets line width in pixels.

Given that Matlab interprets pixels to mean 1/96 of an inch and points are
defined to be 1/72 of an inch, this should mean that Octave merely needs to
inflate sizes by 96/72 == 4/3.

In order to test this, could someone try the following script in Matlab (also
attached) and upload the resulting file?


close all
ver   % Show what version is running
h1 = line ([0 1], [0.1 0.1], 'linewidth', 0.5);
h2 = line ([0 1], [0.2 0.2], 'linewidth', 1);
h3 = line ([0 1], [0.3 0.3], 'linewidth', 2);
h4 = line ([0 1], [0.4 0.4], 'linewidth', 2.75);
h5 = line ([0 1], [0.5 0.5], 'linewidth', 3);
h6 = line ([0 1], [0.6 0.6], 'linewidth', 6);
h7 = line ([0 1], [0.7 0.7], 'linewidth', 12);
h8 = line ([0 1], [0.8 0.8], 'linewidth', 18);
ylim ([0 1]);
print -r300 lwidth.png






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File Attachments:


-------------------------------------------------------
Date: Sat 03 Feb 2018 04:04:31 AM PST  Name: tst_lwidth.m  Size: 459B   By:
rik5

<http://savannah.gnu.org/bugs/download.php?file_id=43158>

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