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%
% feta-params.mf -- global parameters for both feta and parmesan fonts
%
% source file of the GNU LilyPond music typesetter
%
% (c) 1997--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
stafflines := 5;
%
% The design size of a staff should really be the
% staff_space, but we use staffsize for historical reasons.
%
staff_space# := staffsize# / (stafflines - 1);
staff_space_rounded# := staff_space#;
%
% Measuring on pocket scores turns out: stafflinethickness is
% largely independent on staff size, and generally about 0.5 pt.
%
% By request of WL, we tune down the blackness a little
% for increased contrast with beams.
%
%% !! synchronize with paper.scm
save fixed_line_thickness, variable_line_factor;
fixed_line_thickness + variable_line_factor * 5 pt# = 0.50 pt#;
fixed_line_thickness + variable_line_factor * 4.125 pt# = 0.47 pt#;
stafflinethickness# := fixed_line_thickness
+ variable_line_factor * staff_space#;
stafflinethickness_rounded# := stafflinethickness#;
%
% The following tunes the general blackness of the glyphs.
%
linethickness# := stafflinethickness#; %% 0.5 pt#;
linethickness_rounded# := linethickness#;
%
% bigger puff_up_factor, relatively thicker stafflines.
%
% 20 pt = puff_up_factor 0
% 10 pt = puff_up_factor 1
%
puff_up_factor = (linethickness# - 0.1 staff_space#) / (0.1 staff_space#);
stemthickness# := 1.3 stafflinethickness#;
stemthickness_rounded# := stemthickness#;
ledgerlinethickness# := 2 stafflinethickness#;
ledgerlinethickness_rounded# := ledgerlinethickness#;
define_pixels (staff_space, stemthickness, stafflinethickness,
ledgerlinethickness, linethickness);
define_whole_pixels (staff_space_rounded);
define_whole_blacker_pixels (stemthickness_rounded);
define_whole_vertical_blacker_pixels (stafflinethickness_rounded,
ledgerlinethickness_rounded,
linethickness_rounded);
if ledgerlinethickness_rounded > 2 stafflinethickness_rounded:
ledgerlinethickness_rounded := 2 stafflinethickness_rounded;
fi;
%
% Because of the engraving/stamping process, no traditional
% characters have sharp edges and corners.
% The following variable controls the amount of `roundness'.
%
% This is not a meta variable: it is related to absolute sizes.
%
% FIXME: According to [Wanske], only outside corners should be round
% I don't think we do this anywhere -- jcn
%
blot_diameter# = .40 pt#;
if (blot_diameter# * hppp) < 1:
blot_diameter# := 1 / hppp;
fi
if (blot_diameter# * vppp) < 1:
blot_diameter# := 1 / vppp;
fi
define_pixels (blot_diameter);
%
% symmetry
% --------
%
% Some glyphs have to be positioned exactly between stafflines (clefs,
% note heads). This needs some care at lower resolutions.
%
% Most glyphs use the staffline thickness and the space between two
% staff lines as the fundamental parameters. The latter is the distance
% between the middle of one staff line to the middle of the next. To
% say it differently, the value `staff_space' is the sum of one staff line
% thickness and the whitespace between two adjacent staff lines.
%
% Normally, feta's vertical origin for glyphs is either the middle
% between two staff lines or the middle of a staff line. For example, the
% lower edge of the central staff line is at the vertical position
% `-<staffline thickness> / 2', and the upper edge at
% `<staffline thickness> / 2'. Here we need a value rounded to an integer
% (the feta code uses `stafflinethickness_rounded' for that purpose).
%
% If we have an odd number of pixels as the staffline thickness, Metafont
% rounds `-stafflinethickness_rounded / 2' towards zero and
% `stafflinethickness_rounded / 2' towards infinity. Example: `round -1.5'
% yields -1, `round 1.5' yields 2. The whitespace between staff lines is
% handled similarly. If we assume that stafflinethickness_rounded is odd,
% we have the following cases:
%
% o The glyph is centered between three stafflines or five stafflines
% (clef, `c' meter). We have this:
%
% ___________ a
% ___________ 1
% ___________ a
%
% whitespace
%
% ___________ a
% ...... ___________ 1 .................. x axis
% ___________ a
%
% whitespace
%
% ___________ a
% ___________ 1
% ___________ a
%
% As can be seen, we get symmetry if we split staff lines into two
% equal parts `a' and a pixel line with thickness 1. Consequently, we
% use the following algorithm:
%
% . Decrease the height `h' by 1 temporarily.
%
% . Compute the path for the upper half of the glyph.
%
% . Mirror the path at the x axis.
%
% . Shift the upper half one pixel up and connect it with the lower path.
%
% . Restore height and decrease `d' by 1.
%
% o The glyph is centered between two or four staff lines, and the origin is
% the middle of the whitespace. Assuming that the the whitespace consists
% of an odd number of pixels, we have this:
%
% -----------
% b
% 1
% b
% ___________
% b
% .................. 1 ................. x axis
% b
% ___________
% b
% 1
% b
% ___________
%
% For symmetrical glyphs, this leads to a similar algorithm as above.
% Glyphs which can't be constructed from an upper and lower part need
% to be handled differently, namely to shift up the vertical center by
% half a pixel:
%
% ___________
% b
%
% 0.5
% .................. 0.5 ................ x axis
%
% b
% ___________
%
feta_eps := 0;
feta_shift := 0;
feta_space_shift := 0;
% Use this for paths with a slant of 45 degrees to assure that
% the middle point of a penpos gets covered.
pair feta_offset;
feta_offset := (0, 0);
if known miterlimit:
pickup nullpen;
else:
feta_eps := eps;
if odd stafflinethickness_rounded:
feta_shift := 1;
fi;
if odd (staff_space_rounded - stafflinethickness_rounded):
feta_space_shift := 1;
fi;
feta_offset := (0.5, 0.5);
pickup pencircle scaled 1;
fi;
feta_fillpen := savepen;
|
