[Octave-bug-tracker] [bug #52940] Regression with "PaperPosition" and printing

[Dan Sebald]

Follow-up Comment #38, bug #52940 (project octave):

OK, I'm attaching a new changeset that implements what I had described.  The
elements in axes::properties that seem more geared for the renderer have been
moved to the graphics_xform.  That way each opengl_renderer and derivative
object can get its own transform.  The key change here to make gl2ps_renderer
work without the change in figure "position" property is the following:


  (opengl_renderer::setup_opengl_transformation): Move the storage of xform
  to the start of the function then use it to retrieve x_zlim, x_gl_mat1 and
  x_gl_mat2.  Note, parent_pix_size is passed into get_transform() to get
  transform appropriate for on-screen or print mode.


So, that's the basic design change.  All else is either a regrouping of
parameters for convenience *or* a removal of things that no longer need to be
done.  There is a lot of cleanup that anyone interested could do to make this
approach better, but this should do.

I think there is a bug or two currently covered up for FLTK graphics toolkit
by the pre-patch approach of setting and restoring figure properties.  I left
a note in the changeset:


-    ## print() requires figure units to be "pixels"
-    props(end+1).h = opts.figure;
-    props(end).name = "units";
-    props(end).value = {get(opts.figure, "units")};
-    set (opts.figure, "units", "pixels");
-    nfig += 1;
-
     ## graphics toolkit translates figure position to eps bbox (points)
+    ## 1/28/18  This should no longer be necessary, but the FLTK toolkit
+    ## on-screen axes position shifts if this is not restored.
     fpos = get (opts.figure, "position");
     props(end+1).h = opts.figure;
     props(end).name = "position";
     props(end).value = {fpos};
-    fpos(3:4) = opts.canvas_size;
-    set (opts.figure, "position", fpos);


By my way of thinking, there should no longer be a need for changing figure
"units" or "position".  The axes::properties bounding-box code seems to
address this by converting any units to pixels.  However, although the
position property no longer needs to be set for printing, for FLTK toolkit
there is a shift in the on-screen plot without restoring.  The Qt toolkit
seems fine though.  I don't want to concern myself with that though, as it
isn't the real issue--so I left that in for now.

I did test the non-screen-visible printing for Qt and FLTK.  It seems to work
for Qt, but not for FLTK.  So I've made a change that allows Qt toolkit to do
non-visible printing rather than use __osmesa_print__.  Might this obviate the
manual compilation issue for those with Nvidia drivers?

Rik, I'm tempted to drop the use of __guidata__ and just compute the parent
position size internally using the PaperPosition property.  What do you think?

(file #43101)
    _______________________________________________________

Additional Item Attachment:

File name: octave-gl2ps_viewport_print_nonvisible-djs2018jan28.patch Size:29
KB


    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?52940>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.gnu.org/