From 1489b66525103c3762ac1f3dea63214db01a798c Mon Sep 17 00:00:00 2001 From: Philipp Gesang Date: Sun, 19 May 2013 20:08:26 +0200 Subject: add font-dependent letterspacing --- luaotfload-letterspace.lua | 254 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 254 insertions(+) create mode 100644 luaotfload-letterspace.lua diff --git a/luaotfload-letterspace.lua b/luaotfload-letterspace.lua new file mode 100644 index 0000000..fabf62b --- /dev/null +++ b/luaotfload-letterspace.lua @@ -0,0 +1,254 @@ +if not modules then modules = { } end modules ['typo-krn'] = { + version = 1.001, + comment = "companion to typo-krn.mkiv", + author = "Hans Hagen, PRAGMA-ADE, Hasselt NL", + copyright = "PRAGMA ADE / ConTeXt Development Team", + license = "see context related readme files" +} + +local next = next +local nodes, node, fonts = nodes, node, fonts + +local find_node_tail = node.tail or node.slide +local free_node = node.free +local free_nodelist = node.flush_list +local copy_node = node.copy +local copy_nodelist = node.copy_list +local insert_node_before = node.insert_before +local insert_node_after = node.insert_after + +local nodepool = nodes.pool +local tasks = nodes.tasks + +local new_kern = nodepool.kern +local new_glue = nodepool.glue + +local nodecodes = nodes.nodecodes +local kerncodes = nodes.kerncodes +local skipcodes = nodes.skipcodes + +local glyph_code = nodecodes.glyph +local kern_code = nodecodes.kern +local disc_code = nodecodes.disc +local glue_code = nodecodes.glue +local hlist_code = nodecodes.hlist +local vlist_code = nodecodes.vlist +local math_code = nodecodes.math + +local kerning_code = kerncodes.kerning +local userkern_code = kerncodes.userkern + +local fonthashes = fonts.hashes +local chardata = fonthashes.characters +local quaddata = fonthashes.quads + +typesetters = typesetters or { } +local typesetters = typesetters + +typesetters.kernfont = typesetters.kernfont or { } +local kernfont = typesetters.kernfont + +kernfont.keepligature = false +kernfont.keeptogether = false + +local kern_injector = function (fillup,kern) + if fillup then + local g = new_glue(kern) + local s = g.spec + s.stretch = kern + s.stretch_order = 1 + return g + else + return new_kern(kern) + end +end + +local kernfactors = { } --- fontid -> factor + +local kerncharacters +kerncharacters = function (head) + local start, done = head, false + local lastfont = nil + local keepligature = kernfont.keepligature --- function + local keeptogether = kernfont.keeptogether --- function + local fillup = false + + local identifiers = fonthashes.identifiers + local kernfactors = kernfactors + + while start do + local attr = start[attribute] + local id = start.id + if id == glyph_code then + + --- 1) look up kern factor (slow, but cached rudimentarily) + local krn + local fontid = start.font + do + krn = kernfactors[fontid] + if not krn then + local tfmdata = identifiers[fontid] + if not tfmdata then -- unsafe + tfmdata = font.fonts[fontid] + end + if tfmdata then + fontproperties = tfmdata.properties + if fontproperties then + krn = fontproperties.kerncharacters + end + end + kernfactors[fontid] = krn + end + if not krn or krn == 0 then + goto nextnode + end + end + + if krn == "max" then + krn = .25 + fillup = true + else + fillup = false + end + + lastfont = fontid + local c = start.components + + if c then + if keepligature and keepligature(start) then + -- keep 'm + else + c = kerncharacters (c) + local s = start + local p, n = s.prev, s.next + local tail = find_node_tail(c) + if p then + p.next = c + c.prev = p + else + head = c + end + if n then + n.prev = tail + end + tail.next = n + start = c + s.components = nil + -- we now leak nodes ! + -- free_node(s) + done = true + end + end -- kern ligature + + local prev = start.prev + if prev then + local pid = prev.id + + if not pid then + -- nothing + elseif pid == kern_code then + if prev.subtype == kerning_code or prev[a_fontkern] then + if keeptogether and prev.prev.id == glyph_code and keeptogether(prev.prev,start) then -- we could also pass start + -- keep 'm + else + -- not yet ok, as injected kerns can be overlays (from node-inj.lua) + prev.subtype = userkern_code + prev.kern = prev.kern + quaddata[lastfont]*krn -- here + done = true + end + end + elseif pid == glyph_code then + if prev.font == lastfont then + local prevchar, lastchar = prev.char, start.char + if keeptogether and keeptogether(prev,start) then + -- keep 'm + elseif identifiers[lastfont] then + local kerns = chardata[lastfont][prevchar].kerns + local kern = kerns and kerns[lastchar] or 0 + krn = kern + quaddata[lastfont]*krn -- here + insert_node_before(head,start,kern_injector(fillup,krn)) + done = true + end + else + krn = quaddata[lastfont]*krn -- here + insert_node_before(head,start,kern_injector(fillup,krn)) + done = true + end + + elseif pid == disc_code then + -- a bit too complicated, we can best not copy and just calculate + -- but we could have multiple glyphs involved so ... + local disc = prev -- disc + local pre, post, replace = disc.pre, disc.post, disc.replace + local prv, nxt = disc.prev, disc.next + + if pre and prv then -- must pair with start.prev + -- this one happens in most cases + local before = copy_node(prv) + pre.prev = before + before.next = pre + before.prev = nil + pre = kerncharacters (before) + pre = pre.next + pre.prev = nil + disc.pre = pre + free_node(before) + end + + if post and nxt then -- must pair with start + local after = copy_node(nxt) + local tail = find_node_tail(post) + tail.next = after + after.prev = tail + after.next = nil + post = kerncharacters (post) + tail.next = nil + disc.post = post + free_node(after) + end + + if replace and prv and nxt then -- must pair with start and start.prev + local before = copy_node(prv) + local after = copy_node(nxt) + local tail = find_node_tail(replace) + replace.prev = before + before.next = replace + before.prev = nil + tail.next = after + after.prev = tail + after.next = nil + replace = kerncharacters (before) + replace = replace.next + replace.prev = nil + after.prev.next = nil + disc.replace = replace + free_node(after) + free_node(before) + elseif identifiers[lastfont] then + if prv and prv.id == glyph_code and prv.font == lastfont then + local prevchar, lastchar = prv.char, start.char + local kerns = chardata[lastfont][prevchar].kerns + local kern = kerns and kerns[lastchar] or 0 + krn = kern + quaddata[lastfont]*krn -- here + else + krn = quaddata[lastfont]*krn -- here + end + disc.replace = kern_injector(false,krn) -- only kerns permitted, no glue + end + + end + end + end + + ::nextnode:: + if start then + start = start.next + end + end + return head, done +end + +kernfont.handler = kerncharacters + +--- vim:sw=2:ts=2:expandtab + -- cgit v1.2.3