[changeset] print.m (matlab compatibility)

[Ben Abbott]

The attached changeset introduces Matlab compatible printing.

The positioning of the tick-labels, axes-labels, and title has also  
been improved (these seemingly separate features are intertwined).

In any event, some examples exercising the new functionality (note  
these use default terminal fonts (*). If you encounter a problem, let  
me know).

(1) ex: 6x4.5in figure of surfl(peaks) in the formats; eps, pdf, png  
at screen resolution, and png at 300dpi.

set (0, "defaultaxesfontsize", 12)
set (0, "defaultetxtfontsize", 12)
set (0, "defaultaxesfontname", "*")
set (0, "defaultetxtfontname", "*")
figure (1)
clf
surfl (peaks ())
xlabel ("X")
ylabel ("Y")
zlabel ("Z")
title ("surfl (peaks ())")
set (gcf, "paperunits", "inches")
set (gcf, "papersize", [6, 4.5])
set (gcf, "papertype", "<custom>")
set (gcf, "paperposition", [0, 0, 6, 4.5])
print (gcf, "-deps", "test_surfl.eps")
print (gcf, "-dpdf", "test_surfl.pdf")
print (gcf, "-dpng", "test_surfl.png")
print (gcf, "-dpng", "-r300", "test_surfl-300dpi.png")

When viewing the eps file use an app like ghostview so that the image  
displaed reflects the extents of the bounding box. For example, from  
the shell ...

        $ gv test_surfl.eps

Or form Octave, via system()

        > system ("gv test_surfl.eps")

If you have a window's box, you can try gsview (after a download and  
install).

In these 3D examples, the placment of the axes-labels and tick-labels  
is not aesthetically pleasing. I'm not sure how to properly handle  
this, but hope look at it in the future.

(2) ex: contour(peaks) printed on usletter in ps, pdf, png (default  
resolution), and png at 300dpi.

set (0, "defaultaxesfontsize", 10)
set (0, "defaultetxtfontsize", 10)
set (0, "defaultaxesfontname", "*")
set (0, "defaultetxtfontname", "*")
figure (1)
clf
contour (peaks ())
xlabel ("xlabel")
ylabel ("xlabel")
title ("title")
set (gcf, "paperunits", "inches")
set (gcf, "papersize", [8.5, 11])
set (gcf, "papertype", "usletter")
set (gcf, "paperposition", [0.25, 2.5, 8, 6])
print (gcf, "-dps", "usletter.ps")
print (gcf, "-dpdf", "usletter.pdf")
print (gcf, "-dpng", "usletter.png")
print (gcf, "-dpng", "-r300", "usletter-300dpi.png")

When viewing the postscript output, use ghostview or an equivalent so  
that image diplayed reflects the extents of the page, and not the  
bounding box (or you can just print it).

For this 2D example, Octave is making some adjustments to the  
positiong of the axes-labels, tick-labels, and the title. The result  
should look similar to Matlab's default behavior. The result is  
intended to be consistent across miltiple gnuplot terminals. Aqua term  
is a bit of an outlier, in the negative direction. However, the  
Aquaterm result wasn't too good befor.

(3) Try running the demos for "gnuplot_label_offset" from the Octave  
command line to see some examples of how the tick-labels, axes-labels,  
and title are positioned for several differnt situations. These demos  
are intended for evaluation puposes only, and should be removed before  
being committed. In addition, the gnuplot_label_offset function should  
be incorporated into __go_draw_axes__.m.

        demo gnuplot_label_offset

Some qualifiers:

(1) The present status of Octave relies upon the user to properly  
specify the axes "position" and "units" (normalized) properties, as  
well as the figure properties; "position", "units" (pixels),  
"papersize", "papertype", "paperposition", and "paperuntis" (inches).

(2) If the "position" property of the axes-labels and/or title are  
specified it is ignored. These await low level backend support for  
calculating the text extents, which will merit a significant rewrite  
of the gnuplot backend.

Some comments regarding this changeset:

A trivial bug fix is buried in this changeset. "xaxisposition" should  
be "yaxisposition" in __go_draw_axes__:do_tics

-1471   elseif (strcmpi (obj.xaxislocation, "zero"))
+1471   elseif (strcmpi (obj.yaxislocation, "zero"))
 1472     do_tics_1 (obj.ytickmode, obj.ytick, obj.yminortick,  
obj.yticklabelmode,
 1473                obj.yticklabel, obj.ycolor, "y", plot_stream,  
ymirror, mono,
 1474                "axis", obj.tickdir, ticklength, fontname,  
fontsize,
 1475                obj.interpreter);

This implementation adds three new figure properties to allow print(),  
and gnuplot_drawnow(), to communicate with __go_draw_axes__().

        __gnuplot_default_font_size__ = terminal dependent default fontsize.

        __gnuplot_printing_bitmap__ = true when printing bitmaps.

        __pixels_per_inch__ = the dpi of the printed output.

These properties hold necessary information while printing, otherwise  
default values. These properties are only needed when printing, and  
I'd prefer to have them hidden from the user. I'd like to be able to  
delete them after printing. Is there presently a way to do that?

To produce expected results for objects with the fontname "*",  
gnuplot_drawnow() will substitute the same default as used by gnuplot  
itself, or when there are no standard gnuplot defaults, will favor  
Helvetica (for consistency with Matlab).

I've tested this with jwe's changeset that sets the  
defaultaxesfontname and defaulttextfontname to "*", and all work as  
expected for me.

Ben

changeset-print.patch
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