Re: print command

[Michael Godfrey]

On 07/31/2015 12:10 AM, Dmitri A. Sergatskov wrote:

On Thu, Jul 30, 2015 at 3:42 PM, Rik <address@hidden> wrote:

On 07/30/2015 11:48 AM, Michael Godfrey wrote:

Rik,

There seem to be good reasons for coding print() to always
do the printing with visible off for qt and fltk:

1. This avoids the window flickering that seems to accompany the
    printing (if it works at all).
2. This avoids possible problems with graphics hardware versions.

I think we're screwed either way with bug reports pertaining to gl2ps through the visible path or osmesa through the invisible one.  Savannah has several open bug reports about osmesa including failures with Nvidia cards are installed or in MXE-Octave.  See bugs #44478 and #44438.

--Rik

​I really do not think that we should have rely on GL for anything critical.

It could exist here as a "high-performance" option for those who

can  find OS/hardware combo  with a decent GL stack. 

Dmitri.
--
​

Well, it is true that graphics handling is in a mess. Matlab tries to handle this
with choices like (when running on Linux):
address@hidden ~]$ matlab -nodesktop
libGL error: failed to open drm device: Permission denied
libGL error: failed to load driver: i965
libGL error: unable to load driver: swrast_dri.so
libGL error: failed to load driver: swrast
X Error of failed request:  BadValue (integer parameter out of range for operation)
  Major opcode of failed request:  153 (GLX)
  Minor opcode of failed request:  3 (X_GLXCreateContext)
  Value in failed request:  0x0
  Serial number of failed request:  30
  Current serial number in output stream:  33
MATLAB is selecting SOFTWARE OPENGL rendering.
===============================
This is what you may get if you ssh into a Matlab system (R2015a)
And, plotting and printing the plot (to PDF, for example) works.

So, so testing for the the funcionallity of other choices and falling
back to so called "SOFTWARE OPENGL" may be a choice to consider.

In any case, work is needed if users are going to be able to get graphics
output on a reasonable range of systems.

Michael