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Copyright 2009 Taco Hoekwater <taco@luatex.org>
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This file is part of LuaTeX.
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LuaTeX is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2 of the License, or (at your
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option) any later version.
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LuaTeX is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU General Public License along
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with LuaTeX; if not, see <http://www.gnu.org/licenses/>. */
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/* $Id: packaging.h 3261 2009-12-18 11:38:21Z taco $ */
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/* We define some constants used when calling |hpack| to deal with font expansion. */
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exactly = 0, /*a box dimension is pre-specified */
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additional, /*a box dimension is increased from the natural one */
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cal_expand_ratio, /* calculate amount for font expansion after breaking
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paragraph into lines */
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subst_ex_font /* substitute fonts */
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# define substituted 3 /* |subtype| of kern nodes that should be substituted */
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extern void scan_spec(group_code c);
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extern void scan_full_spec(group_code c, int spec_direction);
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extern scaled total_stretch[5];
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extern scaled total_shrink[5]; /* glue found by |hpack| or |vpack| */
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extern int last_badness; /* badness of the most recently packaged box */
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extern halfword adjust_tail; /* tail of adjustment list */
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extern halfword pre_adjust_tail;
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extern int font_expand_ratio; /* current expansion ratio */
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extern halfword last_leftmost_char;
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extern halfword last_rightmost_char;
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extern halfword next_char_p; /* pointer to the next char of an implicit kern */
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extern halfword prev_char_p; /* pointer to the previous char of an implicit kern */
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extern void set_prev_char_p(halfword p);
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extern scaled char_stretch(halfword p);
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extern scaled char_shrink(halfword p);
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extern scaled kern_stretch(halfword p);
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extern scaled kern_shrink(halfword p);
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extern void do_subst_font(halfword p, int ex_ratio);
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extern scaled char_pw(halfword p, int side);
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extern halfword new_margin_kern(scaled w, halfword p, int side);
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# define update_adjust_list(A) do { \
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vlink(A) = adjust_ptr(p); \
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while (vlink(A) != null) \
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extern halfword hpack(halfword p, scaled w, int m, int d);
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extern halfword filtered_hpack(halfword p, halfword qt, scaled w, int m,
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extern scaled_whd natural_sizes(halfword p, halfword pp, glue_ratio g_mult,
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int g_sign, int g_order, int d);
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extern int pack_begin_line;
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# define vpack(A,B,C,D) vpackage(A,B,C,max_dimen,D) /* special case of unconstrained depth */
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extern halfword vpackage(halfword p, scaled h, int m, scaled l, int d);
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extern halfword filtered_vpackage(halfword p, scaled h, int m, scaled l,
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extern void finish_vcenter(void);
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extern void package(int c);
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extern void append_to_vlist(halfword b);
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extern halfword prune_page_top(halfword p, boolean s);
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extern scaled active_height[10]; /* distance from first active node to~|cur_p| */
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# define cur_height active_height[1] /* the natural height */
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# define awful_bad 07777777777 /* more than a billion demerits */
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# define deplorable 100000 /* more than |inf_bad|, but less than |awful_bad| */
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extern scaled best_height_plus_depth; /* height of the best box, without stretching or shrinking */
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extern halfword vert_break(halfword p, scaled h, scaled d);
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extern halfword vsplit(halfword n, scaled h); /* extracts a page of height |h| from box |n| */
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# define box_code 0 /* |chr_code| for `\.{\\box}' */
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# define copy_code 1 /* |chr_code| for `\.{\\copy}' */
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# define last_box_code 2 /* |chr_code| for `\.{\\lastbox}' */
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# define vsplit_code 3 /* |chr_code| for `\.{\\vsplit}' */
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# define vtop_code 4 /* |chr_code| for `\.{\\vtop}' */
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# define tail_page_disc disc_ptr[copy_code] /* last item removed by page builder */
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# define page_disc disc_ptr[last_box_code] /* first item removed by page builder */
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# define split_disc disc_ptr[vsplit_code] /* first item removed by \.{\\vsplit} */
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extern halfword disc_ptr[(vsplit_code + 1)]; /* list pointers */
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Now let's turn to the question of how \.{\\hbox} is treated. We actually
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need to consider also a slightly larger context, since constructions like
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`\.{\\setbox3=}\penalty0\.{\\hbox...}' and
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`\.{\\leaders}\penalty0\.{\\hbox...}' and
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`\.{\\lower3.8pt\\hbox...}'
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are supposed to invoke quite
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different actions after the box has been packaged. Conversely,
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constructions like `\.{\\setbox3=}' can be followed by a variety of
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different kinds of boxes, and we would like to encode such things in an
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In other words, there are two problems: To represent the context of a box,
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and to represent its type.
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The first problem is solved by putting a ``context code'' on the |save_stack|,
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just below the two entries that give the dimensions produced by |scan_spec|.
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The context code is either a (signed) shift amount, or it is a large
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integer |>=box_flag|, where |box_flag=@t$2^{30}$@>|. Codes |box_flag| through
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|box_flag+biggest_reg| represent `\.{\\setbox0}' through
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`\.{\\setbox}|biggest_reg|'; codes |box_flag+biggest_reg+1| through
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|box_flag+2*biggest_reg| represent `\.{\\global\\setbox0}'
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through `\.{\\global\\setbox}|biggest_reg|'; code |box_flag+2*number_regs|
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represents `\.{\\shipout}'; and codes |box_flag+2*number_regs+1|
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through |box_flag+2*number_regs+3| represent `\.{\\leaders}', `\.{\\cleaders}',
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and `\.{\\xleaders}'.
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The second problem is solved by giving the command code |make_box| to all
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control sequences that produce a box, and by using the following |chr_code|
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values to distinguish between them: |box_code|, |copy_code|, |last_box_code|,
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|vsplit_code|, |vtop_code|, |vtop_code+vmode|, and |vtop_code+hmode|,
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where the latter two are used denote \.{\\vbox} and \.{\\hbox}, respectively.
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# define box_flag 010000000000 /* context code for `\.{\\setbox0}' */
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# define global_box_flag (box_flag+number_regs) /* context code for `\.{\\global\\setbox0}' */
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# define max_global_box_flag (global_box_flag+number_regs)
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# define ship_out_flag (max_global_box_flag+1) /* context code for `\.{\\shipout}' */
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# define leader_flag ship_out_flag+1 /* context code for `\.{\\leaders}' */
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extern void begin_box(int box_context);
added
removed
source/texk/web2c/luatexdir/tex/packaging.h
