% Feta (not the Font-En-Tja) music font --  implement Clefs -*-Fundamental-*-
% This file is part of LilyPond, the GNU music typesetter.
%
% Copyright (C) 1997--2012 Han-Wen Nienhuys <hanwen@xs4all.nl>,
% Jan Nieuwenhuizen <janneke@gnu.org>,
% Juergen Reuter <reuter@ipd.uka.de>
%
% The LilyPond font is free software: you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation, either version 3 of the License, or
% (at your option) any later version, or under the SIL Open Font License.
%
% LilyPond is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
% GNU General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.


fet_begingroup ("clefs");

%
% [Wanske] says the bulbs should be positioned about 1/4 right of the
% `arrow'.
%
% TODO: The hair-curve at z6r looks a little awkward.
%

def draw_c_clef (expr reduction) =
	save hair, norm, reduced_ss, right_edge;
	save xoff;

	reduced_ss# = staff_space# * reduction;
	norm# := 2/3 reduced_ss#;
	hair# := 0.06 reduced_ss# + 0.5 linethickness#;
	right_edge# = 15/4 norm# + 2 hair#;
	define_pixels (norm, reduced_ss, right_edge);
	define_whole_vertical_blacker_pixels (hair);

	set_char_box (0, right_edge#, 2 reduced_ss#, 2 reduced_ss#);

	% make unreduced glyph fit exactly into five staff lines
	if reduction = 1:
		h := d := 2 staff_space_rounded;
	fi;

	% assure that the gap between the left and right stem
	% has the same number of pixels as the thickness of the right
	% stem
	draw_block ((0, -d + feta_shift),
		    (3/4 norm + 1/2 hair, h));
	draw_block ((3/4 norm + 1/2 hair + hround (3/2 hair), -d + feta_shift),
		    (3/4 norm + 1/2 hair + 2 hround (3/2 hair), h));

	% assure symmetry
	h := h - feta_shift;

	pickup feta_fillpen;

	xoff = 3/4 norm + 1/2 hair + 2 hround (3/2 hair);
	z5l = (xoff - 3/4 hair, 0);
	z5r = (x4, 0);

	penpos1 (hair - pen_top - pen_bot, -90);
	top z1l = (xoff + norm + hair, h);

	penpos2 (hround (norm - 3/2 hair) - pen_lft - pen_rt, 180);
	rt z2l = (w, h / 2);

	penpos3 (hair - pen_top - pen_bot, 90);
	bot z3l = ((right_edge - xoff) / 2 + xoff,
		   vround (.5 norm - 1.5 hair));

	penpos4 (hair - pen_lft - pen_rt, 0);
	top z4 = (xoff + 1/2 norm + 1/2 hair,
		  vfloor (reduced_ss - linethickness - .2 hair));

	bot z6 = (xoff + 3/4 norm, vround (.5 norm - .5 hair));

	save t;
	t = 0.833;

	save pat;
	path pat;

	pat = z5l{curl 1}
	      .. z4l{up}
	      .. z4r{down}
	      .. z3r{right}
	      ..tension t.. z2r{up}
	      ..tension t.. flare_path (top z1l, 180, 90,
					hair, hfloor (norm - 1/2 hair), -1)
	      ..tension t.. z2l{down}
	      .. z3l{left}
	      .. z6
	      .. z5r{down};

	filldraw pat shifted (0, feta_shift)
		 -- reverse pat yscaled -1 shifted (0, -feta_eps)
		 -- cycle;

	penlabels (1, 2, 3, 4, 5, 6);

	% ugh, should be bulb, not flare?

	draw_staff (-2, 2, 0);
enddef;


fet_beginchar ("C clef", "C");
	draw_c_clef (1.0);
fet_endchar;


fet_beginchar ("C clef", "C_change");
	draw_c_clef (.8);
fet_endchar;


%
% New bulb routine:
%
% Insert a brushed piece of the path, and draw the rest of the bulb
% separately.
%
% The bulb has circular form.  Neat merging of the bulb and brushed path
% is done by playing with tension.
%

def new_bulb (expr start_point, start_angle,
	      outer_tangent_point,
	      end_point, end_angle,
	      big_radius, bulb_radius, flare,
	      direction, turning_dir) =
begingroup;
	save pat, before, after;
	save center;
	save u, v;
	path pat, before, after;
	pair center;

	clearxy;

	center = outer_tangent_point
		 + big_radius * dir (0);
%		 + (big_radius - bulb_radius) * dir (-turning_dir * 90)

	z1' = center + bulb_radius * dir (turning_dir * 180);
	z2' = outer_tangent_point + flare * dir (0);
	z3' = center + bulb_radius * dir (0);
	z4' = center + bulb_radius * dir (turning_dir * 90);
	z5' = center - 0.5 [big_radius, bulb_radius] * dir (turning_dir * 90);

	labels (1', 2', 3', 4', 5');

	before := z3'{dir (turning_dir * 90)}
		  .. z4'{-dir (0)}
		  ..tension 1.1.. z1'{-dir (turning_dir* 90)};
	after := z2'{dir (turning_dir * 90)}
		 .. end_point{dir (end_angle)};
	(u, v) = before intersectiontimes after;

	pat := start_point{dir (start_angle)}
	       .. outer_tangent_point{dir (-turning_dir * 90)}
	       ..tension 1.02.. z5'{dir (0)}
	       .. subpath (0, u) of before
	       .. subpath (v, infinity) of after;

	if direction = 0:
		pat := reverse pat;
	fi

pat
endgroup
enddef;


%
% There is some variation in the shape of bass clefs.
%
% * In some clefs the size of the swoosh tip almost reaches the
%   bottom staff line; in some it crosses the 2nd line from the bottom
%   with a small overshoot.
%
%   The most popular design is where the X part of the tip is aligned
%   with the left bulb boundary, and the Y part ends on the 2nd
%   staffline exactly.  This is what we do.
%
% * The diameter of the bulb is the width of the open space.
%
% * The vertical center of the bulb can be on or slightly above the
%   staff line.
%
% * The vertical position of the dots can be symmetrical around the
%   staffline, centered in the staff space.  The Baerenreiter SCS has
%   the bottom dot raised by approximately 0.1 staff space.
%
% * Uncarefully set music may have overshoots at the top.  We have none.
%
% * It is not exactly clear where the vertical tangent at the right
%   of the swoosh should be.
%

def draw_bass_clef (expr exact_center, reduction) =
	save reduced_ss, swoosh_width;
	save right_thickness, right_offset, tip_protrude;
	save dot_diam, bulb_y_offset, bulb_flare;
	pair tip_protrude;

	reduced_ss# = staff_space# * reduction;
	2.2 dot_diam# = reduction * (staff_space# - stafflinethickness#);
	right_thickness# = 0.37 staff_space# + 1.2 linethickness#;
	swoosh_width# = 2.1 reduced_ss#;
	define_pixels (swoosh_width);
	define_whole_pixels (reduced_ss);
	define_whole_blacker_pixels (dot_diam, right_thickness);

	right_offset = 0.05 staff_space;
	bulb_y_offset := 0.075 staff_space;
	bulb_flare := 2.5 linethickness;
%	tip_protrude := (-linethickness, -.2 staff_space);
	tip_protrude := (0, 0);

	set_char_box (-xpart exact_center,
		      xpart exact_center + swoosh_width# + 7/12 reduced_ss#,
		      -ypart exact_center + 2.5 reduced_ss#,
		      ypart exact_center + reduced_ss#);

	y1 = bulb_y_offset;
	x1 = 0;

	x2 = .5 [x1, x3];
	x2l = x2r = x2;

	y2l := vround_pixels (reduced_ss# + 0.5 linethickness#);
	y2l - y2r = linethickness;

	x3l - x1 = swoosh_width;
	x3l - x3r = right_thickness;

	% optical correction: the top dot seems farther away if y3l = 0.
	y3l = right_offset;

	z4 = -(0, 2.0 reduced_ss) + tip_protrude;

	penpos3 (whatever, 185);
	penpos4 (linethickness, 135);

	fill new_bulb (z2l, 180, z1, z2r, 0,
		       0.45 reduced_ss, 0.4 reduced_ss,
		       bulb_flare, 1, 1)
	     .. z3r{down}
	     .. {curl 0}simple_serif (z4r, z4l, 90){curl 0}
	     .. z3l{up}
	     ..tension 0.9.. cycle;

	pickup pencircle scaled dot_diam;

	lft x5 = hround (x3l + 1/3 reduced_ss - dot_diam / 2);
	bot y5 = vfloor (.5 reduced_ss - dot_diam / 2);
	z6 = z5 yscaled -1;

	% for symmetry
	y5 := y5 + feta_shift;

	drawdot z5;
	drawdot z6;

	penlabels (1, 2, 3, 4, 5, 6);

	draw_staff (-3, 1, 0);
enddef;


fet_beginchar ("F clef ", "F");
	draw_bass_clef ((0, 0), 1.0);
fet_endchar;


fet_beginchar ("F clef (reduced)", "F_change");
	draw_bass_clef ((0, 0), 0.8);
fet_endchar;



%
% Inspired by Baerenreiter
%
%
% Beste lezers, kijk,
%
% Een bolletje hebben we bij toeval allemaal wel eens getekend, maar begint u
% toch eenvoudig.  Eerst een eenvoudig kruis of herstellingsteken
% en via de dubbelslag naar een voorzichtig vlaggetje, en heb geduld!
% Ikzelf heb bijvoorbeeld over mijn eerste gave G-sleutel
% 35 kilobyte metafont, 12 patchlevels, 0 vriendinnen en 45 dagen gedaan
%
%  -- vrij naar Van Kooten & De Bie
%

def debugfill = fill enddef;

def draw_gclef (expr reduction) =
	save reduced_ss, downstroke_dir, downstroke_angle, center;
	save breapth_factor, inner_thick_end, thinness, thickness, thinnib;
	save start_angle, inner_start_angle;
	save upward_swoosh_angle, bot_angle;
	save pat;
	save corr_angle, corr, left_, right_, up_, down_, bot_angle_;
	path pat;
	pair downstroke_dir, center;
	transform corr;
	pair left_, right_, up_, down_;

	reduced_ss# = staff_space# * reduction;
	define_pixels (reduced_ss);

	% G clef has now a smaller upper loop than it used to have.
	% Too small loop in reduced clef (G_change) interacts badly
	% with stafflines, so we make reduced clef's loop a bit bigger.
	reduced_loop_correction := min (max (0.94, (0.6 + 0.46 * reduction)), 1);

	thinness = 0.095 staff_space + 0.75 linethickness;
	downstroke_dir = unitvector (14, -75);
	downstroke_angle = angle downstroke_dir;
	bot_angle = -180;		% downstroke_angle - 87

	upward_swoosh_angle = 132;
	start_angle = -97;

	breapth_factor = 21/14;
	inner_thick_end = 45;
	inner_start_angle = downstroke_angle - 43;
	thickness = .33 reduced_ss + 1.1 linethickness;

	thinnib = thinness;

	set_char_box (0, 1.71 * breapth_factor * reduced_ss#,
		      2.55 * reduced_ss#, 4.8 * reduced_ss# / reduced_loop_correction);

	center := (breapth_factor * reduced_ss, 0);

	z1 = center + whatever * dir (inner_start_angle);
	x1 = xpart center - .28 reduced_ss;
	penpos1 (thinnib, inner_start_angle);

	x2r = xpart center;
	y2r = vround_pixels (reduced_ss# + .5 stafflinethickness#);
	penpos2 (thickness, 90);

	z3 = (z4 - center) rotated inner_thick_end + center;
	penpos3 (thinnib, -90 + inner_thick_end);

	x4 = xpart center - .1 reduced_ss;
	y4r = -y2r + feta_shift;
	penpos4 (thinnib, -90);

	x5r = -breapth_factor * reduced_ss + xpart center;
	y5r = .37 reduced_ss + ypart center;
	penpos5 (thickness, upward_swoosh_angle);

	z6 = center + whatever * downstroke_dir + (-0.02, 0) * reduced_ss;
	y6 = ypart center + 1.95 reduced_ss / reduced_loop_correction;
	% penpos6 is computed later

	z7l - z6 = whatever * (z5 - z6);
	y7l = 3.38 reduced_ss / reduced_loop_correction;
	penpos7 (thickness, upward_swoosh_angle);

	x9 = .75 [x10, x7r];
	top y9l = 4.78 reduced_ss / reduced_loop_correction;
	penpos9 (1.45 thickness, -70);

	x11 - x13r = 1.44 * reduced_ss + 0.5 thinnib;
	y11 = ypart center - 45/28 reduced_ss;
	y12 = ypart center - 69/28 reduced_ss;
	y13 = .48 [y12, y4r];
	x12r = xpart (.45 [z13r, z11] + .75 reduced_ss * downstroke_dir);

%	z10 = center + whatever * dir (downstroke_angle - 1.5);
	x10 = x6 - 1.85 thinnib * reduction / reduced_loop_correction;
	y10 = ypart center + 3.32 reduced_ss / reduced_loop_correction;
	y10l - y10r = 1.0 thickness;
	z10r - z10l = .7 thinnib * dir (downstroke_angle + 90)
		      + whatever * downstroke_dir;
	z10 = .5 [z10l, z10r];
	z11 = center + whatever * downstroke_dir + (0.03 reduced_ss, 0);

	penpos11 (thinnib, start_angle + 90);
	penpos12 (thinnib, bot_angle + 90);
	penpos13 (thinnib + 0.14 staff_space, 180);

	% this auxiliary point ensures good contour overlapping
	z8 = .5 [z9l, z9r] + .25 ((z9r - z9l) rotated -90);

	z20 = z9l - (0, .25 blot_diameter);
	penpos20 (blot_diameter, 0);

	pat := z10{down}
	       .. z6
	       ..tension 1.1.. z11{dir (start_angle)};

	penpos6 (thinnib, angle (direction 1 of pat) + 90);

	% two auxiliary points to simulate `draw' with `penstroke'
	z10' = point 0.3 of pat;
	penpos10' (1.3 thinnib, angle (direction 0.3 of pat) + 50);

	z11' = point 1.5 of pat + (0.033, -0.5) * reduced_ss;
	penpos11' (thinnib, angle (direction 1.5 of pat) + 90);

	z21l = z20l;
	z21r = z9r;

	% after computing all points, we want to rotate the clef
	% rotating the whole picture won't work due to the complexity
	% of the path and metafont's memory limitations, so we transform
	% each point and draw the clef thereafter
	corr_angle := 1.5;
	corr := identity rotatedabout (center, -corr_angle);

	bot_angle_ := bot_angle + corr_angle;

	left_ := left rotated corr_angle;
	right_ := right rotated corr_angle;
	up_ := up rotated corr_angle;
	down_ := down rotated corr_angle;

	% transform points; we transform every point and save it
	% to a shifted index range: z1 -> z101, z2 -> z102, etc.
	for n := 1 upto 21:
		forsuffixes e := l,,r:
			z[n+100]e = z[n]e transformed corr;
		endfor
	endfor

	% transform helper points
	for n := 10, 11:
		forsuffixes e := l,,r:
			z[n+100]'e = z[n]'e transformed corr;
		endfor
	endfor

	pat := z121l
	       .. z110l{down}
	       .. z110'l;

	fill z102l{right}
	     .. z103l
	     .. z104l{left_}
	     ..tension 1.07.. z105l{up_}% inside curve
	     .. z107l{up_}
	     ..tension 1.2.. z120r{curl 1}
	     .. {direction 0 of pat}z120l
	     -- z108
	     -- z109r			% {dir (downstroke_angle + 0)}
	     ..tension 0.8.. z107r{down_}
	     .. z105r{down_}
	     .. z104r{right_}
	     .. z103r
	     .. z102r{left_}
	     ..tension .95.. z101r
	     -- simple_serif (z101r, z101l, 80)
	     -- z101l
	     ..tension 0.85.. cycle;

	penstroke z121e
		  .. z110e{down_}
		  .. z110'e
		  .. z106e
		  .. z111'e
		  .. z111e{dir (-95 + corr_angle)}
		  .. z112e{dir (bot_angle_)};

	fill new_bulb (z112r, bot_angle_, z113r, z112l, bot_angle_ + 180,
		       0.45 reduced_ss, 0.38 reduced_ss,
		       thinnib + .05 staff_space, 1, -1)
	     -- cycle;

	penlabels (range 101 thru 121);
	penlabels (110', 111');

	draw_staff (-1, 3, 0);
enddef;


fet_beginchar ("G clef", "G");
	draw_gclef (1.0);
fet_endchar;


fet_beginchar ("G clef", "G_change");
	draw_gclef (0.8);
fet_endchar;


%%%%
%
% PERCUSSION
%

%
% The percussion clef extent is not coincident with its bbox, since
% the percussion clef needs more space in front than a normal clef.
%

def draw_percussion_clef (expr reduction) =
	save reduced_ss, razt;

	reduced_ss# = staff_space# * reduction;
	define_pixels (reduced_ss);

	set_char_box (-.67 reduced_ss#, 2.0 reduced_ss#,
		      reduced_ss#, reduced_ss#);

	razt := hround (0.45 reduced_ss);

	d := d - feta_shift;

	draw_block ((-b, -d), (-b + razt, h));
	draw_block ((w - razt, -d), (w, h));

	draw_staff (-3, 1, 1);
enddef;


fet_beginchar ("percussion clef", "percussion");
	draw_percussion_clef (1.0);
fet_endchar;


fet_beginchar ("percussion clef (reduced)", "percussion_change");
	draw_percussion_clef (.8);
fet_endchar;


def draw_tab_T (expr pos, siz, slant) =
begingroup;
	save vx, vy;
	pair vx, vy;

	clearxy;

	vx = (xpart siz) * dir 0;
	vy = (ypart siz) * dir 90;

	penpos1 (.75 penh, 100);
	z1 = z2 + (1/6 * vx - .15 * vy);
	penpos2 (hround (.9 penw), 0);
	x2l = hround xpart (pos + .75 vy);
	y2l = ypart (pos + .75 vy);
	penpos3 (penh, -100);
	z3l = pos + .4 vx + vy;
	penpos4 (penh, -90);
	z4 = -.1 vy + .5 [z3, z5];
	penpos5 (.8 penh, -30);
	x5r = xpart (pos + siz);
	y5l = ypart (pos + siz);

	penpos10 (penw, 170);
	z10 = pos + .55 vx + .9 vy;
	penpos11 (.75 [penh, penw], 170);
	z11 = z10 - .5 vy + .025 vx;
	penpos12 (penh, 100);
	z12l = (xpart .5 [z13, z11], ypart (pos - .025 * siz));
	penpos13 (.75 penh, 60);
	z13 = pos + .2 vx + .15 vy;

	% penlabels (range 1 thru 13);

	soft_penstroke (z1e
			..tension 1.1.. z2e
			.. z3e{right}
			..tension 1.5.. z4e
			..z5e)
	  slanted slant shifted (slant * -ypart pos, 0);

	soft_end_penstroke (z10e
			    ..tension 1.5.. z11e
			    .. z12e
			    ..tension 1.1.. z13e{(z13r - z13l) rotated 90})
	  slanted slant shifted (slant * -ypart pos, 0);
endgroup;
enddef;


def draw_tab_A (expr pos, siz, slant) =
begingroup;
	save vx, vy, pat;
	pair vx, vy;
	path pat;

	clearxy;

	vx = (xpart siz) * dir 0;
	vy = (ypart siz) * dir 90;

	penpos1 (.75 penh, -110);
	z1r = pos + .07 vy;
	penpos2 (penh, -75);
	z2r = (.5 [x1, x3], ypart pos);
	penpos3 (.25 [penh, penw], -30);
	z3 = (.45 [x2, x4], .15 [y2, y4]);
	penpos4 (1 [penh, penw], 0);
	z4 = pos + .5 vx + .975 vy;

	penpos5 (1 [penh, penw], -180);
	z5 = z4;
	penpos6 (.2 [penh, penw], -150);
	z6l = (.8 [x5l, x7l], .9 [y5l, y7l]);
	penpos7 (penh,-90);
	z7r = (.5 [x6, x8], ypart pos);
	penpos8 (.75 penh, -70);
	z8r = (xpart (pos + siz), y7r + .075 ypart (siz));

	pat := z2
	       .. z3
	       .. z4;

	penpos10 (penh, angle (direction 1.2 of pat) - 180);
	z10 = point 1.2 of pat;
	penpos11 (.9 penh, -90);
	z11 = .4 [z10, z6] - 0.05 vy;
	penpos12 (.75 penh, -75);
	z12 = .3 [z11, z6] + 0.02 vy;

	% penlabels (range 1 thru 12);

	soft_penstroke (z1e{(z1r - z1l) rotated 90}
			.. z2e
			.. z3e
			.. z4e)
	  slanted slant shifted (slant * -ypart pos, 0);

	soft_end_penstroke (z5e
			    .. z6e
			    .. z7e
			    .. z8e{(z8r - z8l) rotated 90})
	  slanted slant shifted (slant * -ypart pos, 0);

	soft_end_penstroke (z10e
			    .. z11e
			    .. z12e)
	  slanted slant shifted (slant * -ypart pos, 0);
endgroup;
enddef;


def draw_tab_B (expr pos, siz, slant) =
begingroup;
	save vx, vy;
	pair vx, vy;

	clearxy;

	vx = (xpart siz) * dir 0;
	vy = (ypart siz) * dir 90;

	penpos1 (.75 penh, 100);
	z1 = z2 + (.15 * vx - .1 * vy);
	penpos2 (hround (.9 penw), 0);
	x2l = hround xpart (pos + .75 vy);
	y2l = ypart (pos + .75 vy);
	penpos3 (penh, -100);
	z3l = pos + .4 vx + 1.05 vy;
	penpos4 (.8 [penh, penw], -180);
	z4 = (xpart (pos + .75 siz), .5 [y3, y5]);
	penpos5 (.8 penh, 90);
	z5 = (.5 [x10, x4], ypart (pos + .55 siz));

	penpos6 (.8 penh, 270);
	z6 = z5;
	penpos7 (penw, 180);
	z7l = (xpart (pos + siz), .5 [y6, y8]);
	penpos8 (.8 penh, 45);
	z8 = .5 [z12l, z11l] + .15 vx - .05 vy;

	penpos10 (.75 [penh, penw], 170);
	z10 = pos + .375 vx + vy;
	penpos11 (.8 [penh, penw], 150);
	z11 = z10 - .5 vy + .04 vx;
	penpos12 (penh, 100);
	z12l = (xpart .5 [z13, z11], ypart pos);
	penpos13 (.75 penh, 60);
	z13 = pos + .1 vx + .15 vy;

	% penlabels (range 1 thru 13);

	soft_penstroke (z1e
			..tension 1.1.. z2e
			.. z3e
			.. z4e
			..z5e {left})
	  slanted slant shifted (slant * -ypart pos, 0);

	soft_end_penstroke (z6e{right}
			    .. z7e
			    .. z8e{(z8r - z8l) rotated 90})
	  slanted slant shifted (slant * -ypart pos, 0);

	soft_end_penstroke (z10e
			    ..tension 1.5.. z11e
			    .. z12e
			    ..tension 1.1.. z13e{(z13r - z13l) rotated 90})
	  slanted slant shifted (slant * -ypart pos, 0);
endgroup;
enddef;


def draw_tab_clef (expr reduction) =
	save reduced_ss, letterheight, penw, penh;

	reduced_ss# = staff_space# * reduction;
	letterheight# = 1.8 reduced_ss#;
	define_pixels (reduced_ss, letterheight);

	set_char_box (-.2 reduced_ss#, 2.8 reduced_ss#,
		      1.6 letterheight#, 1.6 letterheight#);

	penw = .45 reduced_ss;
	penh = .2 reduced_ss;

	draw_tab_T ((-b + .15 reduced_ss, h - letterheight),
		    (2.1 reduced_ss, letterheight), 0.2);
	draw_tab_A ((-b - .05 reduced_ss, -.5 letterheight +.15 reduced_ss),
		    (2.2 reduced_ss, letterheight), 0.4);
	draw_tab_B ((-b + .025 reduced_ss, -d),
		    (2.1 reduced_ss, letterheight), 0.25);

	draw_staff (-3, 2, 0.5);
enddef;


fet_beginchar ("tab clef", "tab");
	draw_tab_clef (1.0);
fet_endchar;


fet_beginchar ("tab clef (reduced)", "tab_change");
	draw_tab_clef (.8);
fet_endchar;

fet_endgroup ("clefs");
