% Blackboard bold parameters, Alan Jeffrey 14--18 Dec 1989.
%
% These parameters are deduced from those set in bboldNN.mf.
%
% The only horizontal parameter we take in is the unit u#,
% from which we calculate all the horizontal distances.
%
% The distance between the two strokes in a fat line is fatness.
fatness# := 2.3u#;
% The size of a pen is rule_thickness.
pen_size# := rule_thickness#;
% Characters with space inside them (for example the
% gap between the bar and the dot in a ! have either smallspace,
% space# or bigspace# worth of space.
smallspace# := u#;
space# := 2u#;
bigspace# := 3u#;
% Characters with bits jutting out of them (for example the feet in
% ] or the bar in f) have jut# worth of stick-outiness.
jut# := 1.5u#;
bigjut# := 2.5u#;
% Some characters are exactly fatness# + pen_size# wide, as they are
% drawn with just one vertical line.
%
% tiny --- I, i, l, |, ,, :, ;, ., `, ', !.
%
% Others have a small amount jutting out from the side, like the
% top and bottom of a ].
%
% tiny+jut --- [, ], (, ).
tiny# := fatness# + pen_size#;
% Upper case characters come in three sizes:
%
% small --- B, E, F, J, K, L, P, R, S, Gamma, Pi, ?, $, /, \,
%
% medium --- A, C, D, G, H, M, N, O, Q, T, U, V, X, Y, Z,
% Delta, Theta, Lamba, Xi, Sigma, Upsilon, Phi, Psi, Omega,
%
% big --- W.
smallcap# := 9u#;
medcap# := 10u#;
bigcap# := 14u#;
% Lower case characters come in three sizes:
%
% small --- f, j, s, t,
%
% small + fatness --- h, k, n, r,
%
% medium --- a, c, d, e, g, o, q, u, v, x, y, z,
%
% medium + fatness --- b, p,
%
% big --- m, w.
%
% The letters with verticals at the left have fatness added on
% so that the curves are the same size as the other letters.
smalllower# := 6u#;
medlower# := 7.5u#;
biglower# := 11u#;
% Numerals are all the same size.
numeral# := 8u#;
% Arithmetic operators (in this case just +) are all the same size.
arithmetic# := 12u#;
% Characters have three kinds of space at the side:
%
% small --- for example around a T,
%
% medium --- for example around an O,
%
% large --- for example around an I.
smallgap# := 1/2u#;
medgap# := 1u#;
biggap# := 1.5u#;
% Whereas we've only got one horizontal measurement stolen from cmr,
% there are lots of vertical ones. We can use these to work out
% our measurements.
%
% Characters can have various top positions:
%
% ATop --- the top of all capitals, Greek, and some punctuation,
%
% aTop --- the top of lower case without ascenders,
%
% bTop --- the top of lower case with ascenders,
%
% iTop --- the top of i and j,
%
% oneTop --- the top of numerals,
%
% bracketTop --- the top of a bracket (also the top of the body size).
ATop# := cap_height#;
aTop# := x_height#;
bTop# := asc_height#;
oneTop# := fig_height#;
bracketTop# := body_height#;
iTop# := min(x_height# + space# + fatness#, asc_height#);
% The bottoms of characters can be:
%
% aBottom --- the base line,
%
% gBottom --- the bottom of a descender,
%
% bracketBottom --- the bottom of a bracket (also the bottom of the body).
aBottom# := 0pt#;
gBottom# := -desc_depth#;
.5 [bracketBottom#, bracketTop#] = math_axis#; % Brackets are centered.
% Various characters such as A, B, G, e, and 3 have bars in them.
ABar# := .25 [aBottom#, ATop#];
BBar# := .52 [aBottom#, ATop#]; % number nicked from cmr.
GBar# := .50 [aBottom#, ATop#];
eBar# := bar_height#;
threeBar# := .54[aBottom#, oneTop#]; % number nicked from cmr.
% The top of a Q's tail is at QTailTop, and the bottom is at QTailBottom.
QTailTop# := .28 [aBottom#, ATop#]; % number nicked from cmr.
QTailBottom# := aBottom# - comma_depth#; % number nicked from cmr.
% Various sorts of letters have various amounts of curl in them.
%
% CCurl --- the amount the end of a C curls,
% cCurl --- the amount the end of a c curls,
% gCurl --- the amount the tail of a g curls,
% hCurl --- the distance from the bottom of an h to the point where
% the right of the curve becomes vertical.
CCurl# := .2 (ATop# - aBottom#);
cCurl# := .2 (aTop# - aBottom#);
gCurl# := .2 (aBottom# - gBottom#);
hCurl# := .4 (aTop# - aBottom#);
% The numbers five, six and eight have bowls, which are sixBowl# tall.
sixBowl# := aTop# - aBottom#; % These bowls are as tall as an a.
% A less than (and a greater than) is lessthan# tall.
lessthan# := math_spread [5/4x_height#, 3/2x_height#]; % Numbers from cmr.
% Right, I'll now turn these nice sharp measurements into grotty
% approximate pixelly ones.
define_corrected_pixels (o);
define_whole_blacker_pixels
(pen_size);
define_whole_pixels
(fatness, jut, bigjut, smallspace, space, bigspace);
define_whole_vertical_pixels
(CCurl, cCurl, gCurl, hCurl, sixBowl);
define_whole_top_pixels
(ATop, aTop, bTop, oneTop, bracketTop, QTailTop);
define_whole_bottom_pixels
(QTailBottom, aBottom, gBottom, bracketBottom);
pickup pencircle scaled pen_size;
define_good_y_pixels
(ABar, BBar, GBar, eBar, threeBar);
% And now some handy numbers, which I don't need sharp versions of.
aMiddle := .5[aBottom, aTop];
dashMiddle := .61803 [aBottom, aTop]; % Number stolen from cmr.
% I can now set the font parameters for the TFM files, stolen from cmr.
font_normal_space := 6u#;
font_normal_stretch := 3u#;
font_normal_shrink := 2u#;
font_quad := 18u#;
font_extra_space := 2u#;
font_x_height := x_height#;
% And that's that.