ylabel not rotated for enhanced windows terminal

[Benjamin L. <bj...@gm...>]

Hello list,

I ran into another strange behviour with the windows terminal and enhanced text.
With a 4.5.0 CVS snapshot build, when I execute

set term windows enhanced
set ylabel "something in mm^2"
plot [0:2*pi] sin(x) with linespoints

the ylabel is placed horizontally at the top left corner, however if I
do instead

set tem windows enhanced
plot [0:2*pi] sin(x) with linespoints
set ylabel "something in mm^2"
replot

it works as expected.

I tracked it down to do_plot() in graphics.c at line 1632 deciding
that the terminal can't do rotated text.
do_plot() decides so, because WIN_text_angle (in win.trm) returnes
FALSE, because graphwin.rotate is FALSE.
Now graphwin.rotate is set in MakeFonts() in wgraph.c, which
determines, whether the font in question supports being rotated.
MakeFonts() in turn is called (among others) by GraphChangeFont()
which itself is called from drawgraph() with the OP Code W_font.

Ok, so on startup, when the terminal is initialized, graphwin.rotate
is set to TRUE (which is correct), but it gets reset to FALSE during
execution.
This happens, because GraphChangeFont() is called with an empty font
name (not a NULL pointer, but the empty string ""). MakeFonts(), when
presented with a font name which is empty, resets graphwin.rotate to
FALSE.

And at this point I got unsure as to what is the correct way to fix
this problem.

Solution 1)
GraphChangeFont() should test whether the font name is not empty, and
only then really change the font (i.e. silently ignore empty font
names)

Solution 2)
drawgraph() should only call GraphChangeFont() if the font name is not
empty (i.e. silently ignore W_font commands with empty font names)

Solution 3)
GraphChangeFont() should not be called with an empty font name in the
first place.
Such a call is found in WIN_set_font (win.trm) when the fontname is
NULL. Is this correct?
And WIN_set_font(NULL) is called from within WIN_options() with the
remark "font initialization". Is this correct, too?

Solution 4)
deal with it in MakeFonts() directly.

benjamin