-- Copyright (c) 2022-2023 Thomas Kelkel kelkel@emaileon.de
-- This file may be distributed and/or modified under the
-- conditions of the LaTeX Project Public License, either
-- version 1.3c of this license or (at your option) any later
-- version. The latest version of this license is in
-- http://www.latex-project.org/lppl.txt
-- and version 1.3c or later is part of all distributions of
-- LaTeX version 2009/09/24 or later.
-- Version: 0.3
local ID = node.id
local GLYPH = ID ( "glyph" )
local DISC = ID ( "disc" )
local GLUE = ID ( "glue" )
local PENALTY = ID ( "penalty" )
local HLIST = ID ( "hlist" )
local INS = ID ( "ins" )
local SWAPPED = table.swapped
local SUBTYPES = node.subtypes
local SPACESKIP = SWAPPED ( SUBTYPES ("glue") )["spaceskip"]
local LEADERS = SWAPPED ( SUBTYPES ("glue") )["leaders"]
local LBPENALTY = SWAPPED ( SUBTYPES ("penalty") )["linebreakpenalty"]
local NEW = node.new
local REM = node.remove
local PREV = node.prev
local NEXT = node.next
local TAIL = node.tail
local INS_B = node.insert_before
local HAS_GLYPH = node.has_glyph
local T = node.traverse
local T_GLYPH = node.traverse_glyph
local pairs = pairs
local type = type
local U = unicode.utf8
local SUB = U.sub
local GSUB = U.gsub
local FIND = U.find
local FLOOR = math.floor
local GET_FONT = font.getfont
local ATC = luatexbase.add_to_callback
-----
local no_iw_kern = false
function spacekern_no_iw_kern ()
no_iw_kern = true
end
local function round ( num, dec )
return FLOOR ( num * 10^dec + 0.5 ) / 10^dec
end
local function find_first_last ( n, node_type, last )
local d = NEXT
if last then
d = PREV
n = TAIL ( n )
end
while true do
if n and n.id == node_type then
return n
end
if d ( n ) then
n = d ( n )
else
return false
end
end
end
local function check_node ( n, space_check, disc_check, last )
if n.replace then
return find_first_last ( n.replace, GLYPH, last ), space_check, disc_check
end
return n, space_check, disc_check
end
local function find_glyph ( n, d, hlist_check, macro )
if n then
local space_check = false
local disc_check = false
if hlist_check and ( n.id == GLYPH or n.replace and HAS_GLYPH ( n.replace ) ) then
return check_node ( n, space_check, disc_check, d == PREV )
elseif not hlist_check then
if d ( n ) then
n = d ( n )
else
return false
end
end
while not ( n.id == GLYPH or n.replace and HAS_GLYPH ( n.replace ) ) do
if n.id == HLIST and n.head then
local point = n.head
if d == PREV then
point = TAIL ( point )
end
return find_glyph ( point, d, true, macro )
end
if not d ( n ) or n.id == INS or macro and n.id == GLUE and n.width == 0 then
return false
else
if n.id == GLUE and n.subtype == SPACESKIP then
space_check = n
elseif n.subtype == LEADERS or n.id == GLUE and n.stretch > 0 then
return false
end
end
if n.id == DISC then
disc_check = n
end
n = d ( n )
end
return check_node ( n, space_check, disc_check, d == PREV )
end
return false
end
local function make_kern ( head, font, first_glyph, second_glyph, insert_point )
local tfmdata = GET_FONT ( font )
if tfmdata and tfmdata.resources then
local resources = tfmdata.resources
if resources.sequences then
local seq = resources.sequences
for _, t in pairs ( seq ) do
if t.steps and ( table.swapped ( t.order )["kern"] or tfmdata.specification.features.raw[t.name] ) then
local steps = t.steps
for _, k in pairs ( steps ) do
if k.coverage and k.coverage[first_glyph] then
local glyph_table = k.coverage[first_glyph]
if type ( glyph_table ) == "table" then
for key, value in pairs ( glyph_table ) do
if key == second_glyph and type ( value ) == "number" then
if not ( ( first_glyph == 32 or second_glyph == 32 ) and table.swapped ( t.order )["kern"] ) then
insert_point.width = insert_point.width + value / tfmdata.units_per_em * tfmdata.size
end
if first_glyph == 32 or second_glyph == 32 then
insert_point.stretch = insert_point.stretch + value / tfmdata.units_per_em * tfmdata.size * 0.5
insert_point.shrink = insert_point.shrink + value / tfmdata.units_per_em * tfmdata.size * 0.33333
end
end
end
end
end
end
end
end
end
end
return head, disc_node
end
local function check_glyph ( n, d, has_prev_next_glyph, prev_next_glyph )
if find_glyph ( n, d ) then
prev_next_glyph = find_glyph ( n, d )
has_prev_next_glyph = true
end
return has_prev_next_glyph, prev_next_glyph
end
local function make_kerns ( head, n )
local has_prev_glyph = false
local has_next_glyph = false
local prev_glyph = n
local next_glyph = n
has_prev_glyph, prev_glyph = check_glyph ( n, PREV, has_prev_glyph, prev_glyph )
has_next_glyph, next_glyph = check_glyph ( n, NEXT, has_next_glyph, next_glyph )
if has_prev_glyph and prev_glyph.char and prev_glyph.font then
head = make_kern ( head, prev_glyph.font, prev_glyph.char, 32, n )
end
if has_next_glyph and next_glyph.char and next_glyph.font then
head = make_kern ( head, next_glyph.font, 32, next_glyph.char, n )
end
if not no_iw_kern and has_prev_glyph and has_next_glyph and prev_glyph.char and next_glyph.char and prev_glyph.font and next_glyph.font then
local tfmdata = GET_FONT ( prev_glyph.font )
if tfmdata and tfmdata.name then
local font_id = GSUB ( SUB ( tfmdata.name, 1, FIND ( tfmdata.name, ":" ) - 1 ), "\"", "" )
local second_tfmdata = GET_FONT ( next_glyph.font )
if second_tfmdata and second_tfmdata.name then
local second_font_id = GSUB ( SUB ( second_tfmdata.name, 1, FIND ( second_tfmdata.name, ":" ) - 1 ), "\"", "" )
if font_id == second_font_id then
head = make_kern ( head, prev_glyph.font, prev_glyph.char, next_glyph.char, n )
end
end
end
end
return head
end
local function make_short_spaces ( head )
for n in T_GLYPH ( head ) do
if n.char and n.char == 59 and ( not find_glyph ( n, PREV ) or find_glyph ( n, PREV ).char ~= 59 ) then
if find_glyph ( n, NEXT, false, true ) then
local next_glyph = n
next_glyph = find_glyph ( n, NEXT, false, true )
if next_glyph.char and next_glyph.char == 59 then
REM ( head, next_glyph )
local SIZE = 0
if n.font then
local tfmdata = GET_FONT ( n.font )
if tfmdata.size then
SIZE = tfmdata.size
end
end
INS_B ( head, n, NEW ( GLUE ) )
local glue_node = PREV ( n )
glue_node.subtype = SPACESKIP
glue_node.width = round ( SIZE * .16667, 0 )
glue_node.stretch = glue_node.width * 0.5
glue_node.shrink = glue_node.width * 0.33333
local has_next_glyph = false
if find_glyph ( n, NEXT, false, true ) then
next_glyph = find_glyph ( n, NEXT, false, true )
has_next_glyph = true
end
if has_next_glyph and next_glyph.char and next_glyph.char == 59 then
INS_B ( head, glue_node, NEW ( PENALTY ) )
PREV ( glue_node ).subtype = LBPENALTY
PREV ( glue_node ).penalty = 10000
REM ( head, next_glyph )
end
REM ( head, n )
end
end
end
end
end
local function make_glues_and_kerns ( head )
for n in T ( head ) do
if n.id == GLUE and n.subtype == SPACESKIP then
head = make_kerns ( head, n )
end
end
return head
end
ATC ( "ligaturing", make_short_spaces, "make short spaces", 1 )
ATC ( "pre_linebreak_filter", make_glues_and_kerns, "kern between words and against space preline", 1 )
ATC ( "hpack_filter", make_glues_and_kerns, "kern between words and against space hpack" )